Almost a century ago, on 17 July 1925, one of the greatest German painters of modern times died. From the early 1880s until then, Lovis Corinth painted prolifically in every genre from classical myths to landscapes. At the height of his career in December 1911 he almost died as the result of a major stroke, but with the devoted support of his wife he learned to paint again. In this series I look at a selection of his paintings, and how they changed over the course of more than forty years.

He was born Franz Heinrich Louis Corinth in the village of Tapiau, in what was then the northern part of East Prussia, and is now the town of Gvardeysk near Kaliningrad, Russia. He was schooled in the city of Königsberg (now Kaliningrad), and soon resolved to be an artist. He started attending the Academy of Fine Arts in Königsberg in 1876, where he decided that he wanted to be a history painter, and concentrated on painting the figure.

On the advice of his teachers in Königsberg, Corinth moved to Munich in the spring of 1880, where he initially studied with Franz von Defregger. At that time, Munich almost rivalled Paris as a progressive centre for the arts, and had been the preference of William Merritt Chase, who had left Munich only two years previously. Corinth learned both traditional and modern techniques of oil painting in the studio of Ludwig von Löfftz, where he concentrated on painting from life.

Even his earliest figures, such as his Crucified Thief from 1883, were powerful, and showed influence from the Dutch Masters.

Like William Merritt Chase, Corinth was particularly fond of the work of Van Dyck and Frans Hals, as revealed in his portrait of Laughing Girl (1883).

Black Othello (1884) was probably his first success, and was exhibited to acclaim in Königsberg. That same year another of his paintings won a bronze medal in London, and was exhibited at the Salon in Paris the following year.

Corinth completed his training in Munich in 1884, and moved to Antwerp for a few months, before he settled in Paris that autumn. There he enrolled in the Académie Julian, where he studied under Bouguereau and Robert-Fleury, and concentrated on female nudes and building his repertoire of mythological scenes. He was influenced by the 1885 retrospective exhibition of the works of Jules Bastien-Lepage, who had died suddenly in 1884, and that aided a move towards greater naturalism.

Examples of his paintings from life from his time in Paris include his study of a Nude Girl (1886) above, and below of a Sitting Female Nude from the same year.

In 1886 he visited Germany, and painted some landscapes and portraits en plein air on the Baltic coast near Kiel. When he returned to Paris that autumn, he was becoming increasingly frustrated by his inability to achieve success at the Salon. He only had two paintings accepted there, in 1885 and 1887, and neither had achieved critical success or a medal. He left Paris, and joined the Nasser Lappen (‘Wet Rags’) group in Berlin for a while, trying to progress his history painting. It was then that he painted his first self-portrait.

This Self Portrait of 1887 shows Corinth at the age of twenty-nine in Berlin.

In 1888, he returned to Königsberg, adopted the name of Lovis Corinth, and started to find form at last. Woman Reading shows his early style maturing well, with its subtle use of light.

His father, who had been a successful tanner, fell ill, prompting Corinth’s sensitive painting of his final illness in Father, Franz Heinrich Corinth, in Hospital (1888). After his father died early the following year, Corinth became financially independent, and set up a proper studio in Königsberg at last.

He painted portraits, including this of Franz Lilienthal (1889), another East Prussian student at the Académie Julian. That same year he was inspired by an exhibition of the work of contemporary German painters including von Lenbach, Böcklin and von Uhde, as a result of which he finally obtained an honourable mention at the Salon in 1890.

That year he painted one of his most accomplished early portraits, Innocentia (1890), and made his first attempts at a history painting of a popular narrative.

Corinth painted two versions of Susanna Bathing (Susanna and the Elders) in 1890: that above, now in the Museum Folkwang, and that below, thought to be in a private collection.

The story of Susanna (or Shoshana) and the Elders is told in the Old Testament book of Daniel, chapter 13, and centres on voyeurism, blackmail, and justice. Susanna was a beautiful married woman who was bathing in her garden one afternoon, having dismissed her servants. Two lustful elders spied on her, and as she returned to her house they stopped her, and threatened that, unless she agreed to have sex with them, they would claim that she had met her lover in the garden. Being virtuous, Susanna refused their blackmail, and was promptly arrested, charged with promiscuity, and awaited her execution.

The young prophet Daniel interrupted the process, demanding that the elders should be properly questioned before such a severe penalty was applied. When questioned individually, the two elders gave different accounts, most notably in the type of tree under which Susanna allegedly met her lover. The accusations were thus revealed to be false, Susanna was acquitted of the charge, and the two elders were executed instead.

From the early Renaissance, this has been a popular story in painting, almost universally depicted as a nude bather being spied on by two nasty old men. As narrative, this is weak, as the crux is the conflicting evidence of the elders, which is much harder to paint, and is usually just an excuse to paint a female nude with some gratuitous anti-semitism.

Corinth shows what had become a fairly traditional version, in which Susanna is seen in the flesh but not under any tree in the garden: she is instead being spied on from behind a curtain, with only one of the two elders clearly visible.

Of his two versions, that in the Museum Folkwang appears the less finished, but both emphasise Susanna’s nakedness with her clothes, and add refinements by way of her discarded jewellery and a flower from her hair. Her figure reflects the effort that Corinth had put into life studies, and makes his simple composition successful.

References

Wikipedia.

Lemoine S et al. (2008) Lovis Corinth, Musée d’Orsay & RMN. ISBN 978 2 711 85400 4. (In French.)
Czymmek G et al. (2010) German Impressionist Landscape Painting, Liebermann-Corinth-Slevogt, Arnoldsche. ISBN 978 3 89790 321 0.

The ability to save Spotlight searches is perhaps its most underused feature. This article explains how Saved Search and Smart Folders work, and how you can use them to your advantage.

Save a search

Open a new Finder window and turn it into a Find window using the Find command at the foot of the File menu. Leave its search box blank, and set up one or more search bars with criteria that find some files of interest.

Then click on the Save button at the upper right, just below the search box. In the save dialog, set the saved location to an accessible folder such as ~/Documents, leave the Add To Sidebar checkbox empty, and click Save.

Close that Find window, and select your Saved Search ‘folder’ in the Finder. That will display the same files you just found in that search, as if it was a normal folder. Select any of those files, though, and you’ll see that they’re not really there, and their paths are for the original file, as if they were symbolic links, perhaps.

You can now move that Saved Search around, even copy it to another Mac, and wherever it goes it performs the same search and shows the results. Open Get Info on the Saved Search item and it’s described as a Saved Search Query, and the predicate used internally by Spotlight for that search is shown as its Query.

Edit a search

Now double-click on the Saved Search item to open it in its own window, and click on the Action tool (the circle containing an ellipsis …) and select the Show Search Criteria item in the menu. This restores your original Find window, complete with all its original settings, search bars, and their contents.

You can now change that search, and it will update to show the new results. To save your modified search, click on the Save button at the upper right, and the Saved Search will be duly updated.

Saved Search and Smart Folders

You can do exactly the same starting from the Finder’s New Smart Folder command in its File menu, as that creates a new Find window with identical features. The end results are the same, a file of type com.apple.finder.smart-folder. Only, as you’ll have gathered by now, this isn’t a real folder at all, just a property list that the Finder handles in an unconventional way.

Open the .savedSearch file using a text editor (you can make that easier by changing its extension to .plist if you wish), and you’ll see that it doesn’t even list the files ‘contained’ by this ‘folder’, all it gives is the search predicate used by Spotlight to find the items that are shown as being inside it.

That predicate, also shown as the Query in the Get Info dialog, is saved in the property list against its RawQuery key. Much of the rest of the property list is devoted to details enabling the Finder to reconstruct the Find window should you should decide to Show Search Criteria. But nowhere does it list any of the items found in the search.

This ensures that Saved Searches and Smart Folders take almost no space, just a few KB for that property list, and unless they’re open and displaying the search results, they don’t take any memory either.

They also don’t behave like regular folders. You can’t add items to them except by changing the search criteria used. You can only copy items from them, and can’t remove anything either. If you duplicate a Saved Search then you simply get another copy of the property list, not the items found by it. Their contents are also dynamic: create another item that meets their search criteria, and that will automatically be added to their contents, hence the alternative name of Smart Folder.

They’re also versatile and can have several roles:

• to return to a search still in progress;
• to set defaults for future Find windows, laid out ready for fresh searches;
• as records of important searches you might wish to repeat;
• as templates for types of search you’re likely to repeat.

They’re also the only place that I’m aware of that provides a bridge between searches made using the GUI in the Finder, and the terms and format of predicates used internally and by mdfind. This is important, as Saved Searches are themselves of no use in the command line, but their Query string can be used directly, as I’ll demonstrate in a later article.

Key points

• Saved Search = Smart Folder;
• they aren’t folders at all, but reconstruct and replay the search in a Find window;
• change the search by opening the Saved Search and using Show Search Criteria in the Action menu;
• their Query gives the search predicate used.

Once the god Aesculapius is ensconced in his temple on Tiber Island in the city of Rome, Ovid is ready to round off his Metamorphoses with salient points from the life of Julius Caesar, and links to the contemporary Emperor Augustus. These are politically charged topics, and merit inoffensive coverage and language. In his whirlwind summary of some of Julius Caesar’s achievements, Ovid is obliged to write that it was Augustus who was the greater, before tackling the thorny issue of Caesar’s assassination.

When swords were taken into the Senate House in preparation, Venus pleaded Caesar’s case, and Jupiter responded that the emperor’s life was already complete, and it was time for him to join the gods. Venus then descended quickly and rescued Caesar’s soul as he lay dying on the floor of the Senate. Julius Caesar therefore underwent transformation into a star (catasterisation) as his apotheosis, on his assassination.

Caesar’s assassins were senators of Rome, a group of more than thirty led by three conspirators including his former friend and ally Marcus Junius Brutus. Several of Caesar’s closest aides had warned him not to attend the Senate on the Ides of March, and he had to be brought by one of the conspirators. As he arrived at the Senate, Caesar was presented with a petition, and the conspirators crowded around him.

Karl von Piloty’s The Murder of Caesar from 1865 shows this moment, with Julius Caesar sat on a throne in the portico of the Senate. Immediately behind him, one of the conspirators has raised his dagger above his head, ready to strike the first blow.

Casca, one of the conspirators, produced his dagger and struck the dictator a glancing wound in his neck. The whole group closed in and stabbed Caesar repeatedly.

This is the stage shown by Vincenzo Camuccini in The Assassination of Julius Caesar from 1804-05, although this isn’t taking place on the steps in the portico, and Caesar has already moved forward from his seat.

Blinded by his blood, Caesar then tripped over and fell, and was stabbed further on the lower steps of the portico of the Senate. The conspirators made off, leaving Caesar dead where he lay, with around twenty-three knife wounds.

In Jean-Léon Gérôme’s The Death of Caesar from 1859-67, Caesar’s corpse lies abandoned on the floor, as his assassins make their way out of the Senate, brandishing their daggers above their heads.

None of those paintings shows the goddess Venus or Caesar’s apotheosis.

It’s Virgil Solis’s engraving of The Deification of Julius Caesar (before 1562) that shows simultaneously the assassination of the dictator at the left, and Venus taking him up to the gods, above, where Jupiter is addressing the other gods (upper right).

Shakespeare’s play develops subsequent events in more detail, and contains two most memorable lines: Et tu Brutus? (“you too, Brutus?”), said when Brutus stabs Caesar, and Friends, Romans, countrymen, lend me your ears as the opening words of Brutus’ oration over Caesar’s corpse.

Later, as Brutus and Cassius prepare to wage war against a triumvirate of Mark Antony, Octavius (later granted the honorific name Augustus) and Lepidus, Caesar’s ghost appears to Brutus to warn of his imminent defeat.

This engraving of Richard Westall’s painting Brutus and the Ghost of Caesar, from about 1802, shows Brutus in his role of general, sat at a writing desk, as Caesar’s ghost fills the upper left of the painting, warning Brutus of his imminent death with the portentous words Thou shalt see me at Philippi.

William Blake painted a similar scene in his Brutus and Caesar’s Ghost from 1806, for an illustrated folio edition of Shakespeare from 1632. This series of illustrations for this play are not well-known among Blake’s work, and were made early in his career.

Edwin Austin Abbey, in his painting Within the Tent of Brutus: Enter the Ghost of Caesar from 1905, spatters the white robe of the ghost with the blood from multiple stab wounds.

With Julius Caesar dead, it’s time for Ovid to draw his Metamorphoses to a close by praising the Emperor Augustus.

I hope that you enjoyed Saturday’s Mac Riddles, episode 310. Here are my solutions to them.

1: London to Pontarddulais in Macs for six months.

Click for a solution

M4

London to Pontarddulais (route of the M4 motorway in Britain) in Macs for six months (first shipped in Macs last November).

2: Jupiter’s flash now reaches 80 for the Pros.

Click for a solution

Thunderbolt 5

Jupiter’s flash (a thunderbolt) now reaches 80 (it offers 80 Gb/s transfer rates) for the Pros (it’s available in M4 Pro and Max chips).

3: Very long run from the Thames to Eastleigh came to the workshop in March.

Click for a solution

M3 Ultra

Very long run (an ultra) from the Thames to Eastleigh (route of the M3 motorway in England, from Sunbury-on-Thames) came to the workshop in March (first available in the Mac Studio of March 2025).

The common factor

Click for a solution

They’re all new hardware in Macs released over the last six months or so.

I look forward to your putting alternative cases.

The most common problem reported in Spotlight search is failure to find target file(s). In this series of articles, I’ll examine what can go wrong, and how you can make local searches more successful using features in macOS. I’m well aware that there are other utilities for searching, some relying on Spotlight, others working independently, but here I’ll confine myself as much as possible to what’s provided in macOS.

Successful searches using Spotlight have four essential requirements:

• The target file(s) must have had their metadata added to Spotlight’s volume indexes.
• Those metadata must be accessible to the tool used to perform the search.
• The search queries used must be capable of finding the target(s).
• Spotlight’s search must work correctly.

Check indexes and access

The first of those can be checked using the mdimport command tool in Terminal, using the command
mdimport -t -d3 [filepath]
where [filepath] is the path of the file. You can vary the digit used in the -d3 option from 1-3, with larger numbers delivering more detail. For -d3 you’ll first be given the file type and mdimporter used, following which all the data extracted is given according to its Spotlight attributes:
Imported '/Users/hoakley/Documents/SpotTestA.rtf' of type 'public.rtf' with plugIn /System/Library/Spotlight/RichText.mdimporter.
37 attributes returned
followed by a long list.

If the file hasn’t been indexed, this article works through the steps you can take to rectify that. Note that recent experience is that using mdutil -E / to erase and force rebuild of indexes on the Data volume may not work as expected, and you should either perform this in System Settings, or using the command mdutil -E /System/Volumes/Data

Which tool?

Global Spotlight is accessed through the magnifying glass icon in the right of the menu bar, or using the default key combination of Command-space. This includes website content, and isn’t ideal when you’re searching for local files. If you want to use this as an easy gateway to local search, enter the text you want to search for and scroll down to use the command Search in Finder, which opens a Finder Find window for the results of that search query. Alternatively, you can click on Show More in the Documents section of the search results.

Local Spotlight can also be opened by the Find command at the foot of the Finder’s File menu, and takes you straight to its search box, at the right of the toolbar in that Finder window.

This window offers a choice of two search scopes at the upper left. The first covers all the accessible contents of that Mac, and the second is the folder open in that window when it was converted to a Find window. To set the scope for a local Spotlight search, start from a normal Finder window with the target folder open, then use the Find command on that.

Searching

Typing text into the search box at the right of the toolbar then performs live or incremental search for both filenames and content at the same time, or you can select one of them in the menu.

Text entered into the search box can simply be the start of a word in the target, or can be a basic search query such as name:"target"*cdw. I will explain those in a later article about search queries.

Instead of, or in addition to, entering text in the search box, you can set further search criteria in search bars below that.

In this case, the file Name is required to contain the string entered in the text box. Add more of these search bars for additional criteria to narrow your search.

Search attributes

In search bars, the first popup sets the metadata attribute to use in the query. For example, both Name and Filename refer to the name of the file, although Name is given in its localised form. Many more options are available by selecting the Other… item at the foot of the attribute menu. You can either set those as a one-off, or add them to the menu of attributes if you’re likely to use them again. These roughly correspond to the metadata attributes as in formal Spotlight search queries used elsewhere, although their names are different.

The second popup sets the operator to be used. While they may appear self-explanatory, two merit fuller explanation as they may work differently from how you might expect:

• matches finds the start of words found by breaking the whole string at word boundaries (see below). Thus it will find danger and danger-es in one-danger-est, but won’t find anger there.
• contains is applied without reference to word boundaries, and simply finds the given string, regardless of what characters occur before or after that. Thus it will find anger in dangerous. It has one unusual behaviour, though: it ignores hyphens, so dangeres will be found in the string danger-est.

Word boundaries

These are crucial in search queries run from the search box in a Find window, and the matches operator used in a search bar below. Although the search box claims to use the contains operator, it actually behaves as the matches operator does in a search bar.

In many languages word roots and meaning appear at the start of words, with declensions and conjugations at the end. If you want to find words related to harvest, like harvester, harvesting and harvested, then you’re going to enter a search query using harvest rather than vest. Like other search engines designed for live or incremental search, Spotlight is fastest when searching for the start of words. It therefore divides compound words often used for filenames into component words. It does so using rules for word boundaries laid down in the International Components for Unicode.

In practice, word boundaries include a space, the underscore _, hyphen – and changes of case used in CamelCase. Spotlight treats each of the following examples as three words:
one target two
one_target_two
one-target-two
OneTargetTwo
Languages other than English may allow other word boundaries, but those are the most common.

The rules recognise that hyphens are difficult, and Spotlight makes them even trickier as it can ignore them altogether when searching for an arbitrary string without word boundaries, and will then happily find netargett in one-target-two! Spotlight also struggles with multiple hyphens mixed with underscores. For example, it may not be able to find danger in the file name a_a-b-c-e-danger_z.txt when using matches, but should work as expected when using contains instead.

Other tools in macOS

In-app search or Core Spotlight relies on search features provided by the app, for example that in Mail. Although these use Spotlight’s indexes and its query language, their function is different from Global or Local Spotlight, and implemented through a distinct Core Spotlight API.

The primary command tool for performing Spotlight search is mdfind, which uses formal query strings and predicates. I’ll tackle those in a future article.

Recommendations for successful search

• To perform local search of files indexed by Spotlight, use a Find window in the Finder.
• Limit search scope by folder when possible, by opening the folder in a Finder window then converting it into a Find window using the menu command.
• For the quickest results, type the start of a distinctive word in the file name or content into the search box.
• For the most inclusive results, leave the search box empty and construct a series of search bars to limit the list of hits.
• Limit the type of files when possible, using the Kind metadata attribute in the first popup menu.
• For file names with a limited number of hyphens and underscores as word boundaries, use Name matches with the start of a word included in the localised file name.
• For file names with more word boundaries, use Name contains with a distinctive target string.

I’m very grateful to Aldous and to Thomas Tempelmann for their unstinting help in understanding word boundaries and their importance, and for solving the mystery of Cleta.

By the 1880s, some established painters had begun to use photographs in the development of their paintings, although they appear to have kept quiet about those techniques. During the next decade this became more widespread, and raised the question of whether photography should be accepted as a new art.

In the 1890s Edgar Degas experimented with photography. This is an albumen print of patron and amateur painter Henry Lerolle with two of his daughters, Yvonne and Christine, taken by Degas in 1895-96.

Degas also took this self-portrait with Christine and Yvonne Lerolle in the same period.

In Degas’ oil painting of After the Bath from about 1895, the woman has adopted a strange and unnatural position, as if she has almost fallen from the edge of the deep bath. Her left foot is still cocked over its edge, as the rest of her lies on her right side on a towel. A maid stands behind her, attending to her long hair.

Degas didn’t just draw and paint women bathing, but made photos as well, such as this print of After the Bath, Woman Drying Her Back from 1896.

The realist painter Jean-Léon Gérôme not only experimented with photography for many years, but was an enthusiastic advocate for its recognition as an art in its own right.

Gérôme’s Truth Coming out of her Well to Shame Mankind (1896) is based on a quotation attributed to Democritus, “Of a truth we know nothing, for truth is in a well” (or, more literally, ‘in an abyss’). Gérôme used the same allusion in his preface to Émile Bayard’s posthumous collection of collotype plates of photographs of nudes, Le Nu esthétique. L’Homme, la Femme, L’Enfant. Album de documents artistiques inédits d’après Nature, published in 1902, where he wrote:
Photography is an art. It forces artists to discard their old routine and forget their old formulas. It has opened our eyes and forced us to see that which previously we have not seen; a great and inexpressible service for Art. It is thanks to photography that Truth has finally come out of her well. She will never go back.

It’s almost certain that Jules-Alexis Muenier became a photographer between 1880, when he went to Paris to study at the École des Beaux-Arts, and when he travelled to North Africa with Pascal Dagnan-Bouveret in 1888, armed with cameras. Although he may have found it difficult to set up the necessary darkroom and processing laboratory when he was still living in Paris, in 1885 he moved to a large house on his parents-in-law’s estate in Coulevon, which should have been ideal.

Although I have been unable to find a suitable image of the painting, this photograph shows Muenier with his painting of The Harpsichord Lesson in about 1911, which became his most famous painting during his lifetime. Muenier, Gérôme and Dagnan-Bouveret weren’t just happy snapper photographers, but believed in photography as fine art. All three were early members of local photographic clubs, and Muenier and Dagnan-Bouveret exhibited their photographs as seriously as their paintings.

Franz von Stuck’s remarkable Dancers (1896) is one of his earlier paintings exploring images of dancing women. This seems to have been inspired by some of the more flamboyant dresses of the day, and as an experiment in the portrayal of motion, in turn influenced by contemporary photography.

Joaquín Sorolla’s portrait of The Photographer Christian Franzen from 1903 brings this full circle. Franzen (1864-1923) was Danish by birth, trained in Copenhagen, then worked throughout Europe until he established his studio in Madrid in 1896. He was appointed court photographer to King Alfonso XIII.

By the twentieth century, some of the most prolific and painterly painters were also dedicated photographers.

Marthe in the Bathtub (1907) is one of the thousands of photos of Marthe taken by Pierre Bonnard.

Kneeling Woman or Nude with Tub from 1913 is a painting that surely reflects Bonnard’s photographs.

I Werners Eka (In Werner’s Rowing Boat) from 1917 is one of Anders Zorn’s last great paintings of a nude outdoors.

Zorn had also been an enthusiastic photographer who used photos for his paintings. This undated print was taken At Lake Siljan, close to his home town of Mora.

To finish, I leap forward a century to the painstakingly real paintings of Ellen Altfest. To ensure her painted representations are exact, she measures angles with metal skewers, and places marks to maintain her orientation in forests of hair. She eschews grids and projections so she can retain a sense of herself, and not lapse into mechanical reproduction. She only paints in natural light, and often outdoors.

The end result is nothing like a photograph. Her oil paintings result from the most prolonged and intense looking, and slow, meticulous painting. I feel sure that Gérôme would have loved them.

How everything grows over time. Twenty years ago a hard disk of 100 GB was often ample, now twenty times that can be insufficient, and some have even larger media libraries. Finding files from among tens of thousands used to be straightforward, but now we’re working with millions we’re often struggling. Last week’s discussions of Spotlight search and its alternatives highlighted how important search strategies have become.

Strategy

Perhaps the most common strategy we use to search quickly and effectively is to apply a series of properties or attributes narrowing from the general to the specific: a dog, a small dog, a small grey-and-white dog, a small grey-and-white Havanese dog. In just a few adjectives we have narrowed the field to a description applying to a small number of domestic pets.

This strategy has two essential requirements: the target of your search must be included in the list of items being searched, and each of the attributes or criteria you apply in succession must include the search target. The first is obvious and critical to Spotlight’s success, and the second is the basis of how attributes are chosen. If the dog’s colour had been specified as red, then that search would have failed.

One of many skills in successful searching is judging how exclusive each criterion should be, and being more inclusive to ensure none of the criteria might inadvertently exclude the target.

Although you can combine attributes in this way when searching using the general Spotlight search window accessed through the menu bar, that’s a global search including websites and everything searchable from Wikipedia to Photos albums and Messages. When looking for a file, searching in the Finder immediately narrows the scope, and saves you wading through many irrelevant results. You can then add a search bar for each criterion, perhaps specifying that you’re looking for an image in your ~/Documents folder, each time reducing the number of hits until your choice becomes sufficiently limited.

Incremental search

Spotlight offers another technique that has become popular in search engines as their performance has improved, in what’s known as live or incremental search. As you type letters into one of its search boxes, it shows results as it gets them. This isn’t much use when entering common combinations of letters, but as they become more specific this can save time and accommodate any uncertainty you might have over spelling or the rest of the word. I use this frequently in MarsEdit when looking for old articles I have written: for example, typing wrestl will find wrestler, wrestlers, wrestling, wrestled, etc.

This works well with most languages including English, where roots and meanings are concentrated in the first parts of words, and declension and conjugation are usually found in their endings. Not all languages work like that, though, and this may not perform as well in Georgian or even German due to their morphology.

Predicates

For those who prefer to use the command line, mdfind can use predicates to express combinations of attributes, but those aren’t readily used in the same incremental way to narrow results down interactively. Another situation where predicates often come into play is when searching log entries and using the log show command, and that brings me on to LogUI, my other concern last week.

Searching the log

Let’s say you want to discover all the information RunningBoard gathers about an app, something you know is written in a log entry by the com.apple.runningboard subsystem shortly after that app starts its launch sequence. While you could search for all entries for that subsystem in the minute or so around the time you launched the app, there are likely to be thousands of hits.

To narrow down that search you have several options, including:

• launch the app at a known time, and set that as the Start time, with a Period of just a couple of seconds;
• set a one-off predicate to subsystem == "com.apple.launchservices" OR subsystem == "com.apple.runningboard";
• search subsystems for com.apple.launchservices to identify the time that LaunchServices announces the app will be launched through RunningBoard;
• search messages for constructed job description, RunningBoard’s log entry giving the details you’re looking for.

Those are ordered in increasing specificity, reducing numbers of hits, and increasing requirement for prior knowledge. That’s a general association, in that the more prior knowledge you have, the more specific you can make your criteria, and the fewer irrelevant hits you will see. As with Spotlight search, the more of these criteria you apply, the greater your chance of success, provided they all match the entry you’re looking for.

LogUI

To make LogUI more amenable to incremental search strategies, two additional features are needed. Instead of only exporting whole log extracts to Rich Text, the app needs to save and read formatted extracts. It also needs the ability to eliminate entries that don’t meet search criteria. Together those will enable use of a predicate to save an extract of reduced size, then application of search criteria, maybe saving an even smaller extract.

One way to combine multiple searches is to use multiple search bars, in a similar way to the Finder’s Find window. However, that tends to become overcomplicated, and I suspect is relatively little-used. If you do need a series of search criteria, then you also need different ways of combining them, including OR as well as AND, and that becomes a GUI predicate editor. I have yet to see any successful GUI predicate editor.

Next week, in the days prior to WWDC, I’m going to be focussing on search strategies for Spotlight, before turning to LogUI to implement these changes. This is an ideal time to let me know what you’d like to see, and how LogUI can support more successful search.

Painters were among the pioneers of photography, as many of them used the camera obscura or camera lucida as an optical aid to drawing. But until the early nineteenth century there was no practical way to fix that image to make it permanent. As various chemical processes were developed and improved to the point where photographs became readily available, painters saw the threat to their effective monopoly, particularly in the lucrative business of portraits.

Photography quickly became all the rage. A few famous painters had their portraits taken: in 1847, John Jabez Edwin Mayall made a daguerreotype of JMW Turner, just four years before his death, and went on to take the first carte-de-visite photos of Queen Victoria in 1860.

The camera in Frederick Daniel Hardy’s The Young Photographers (1862) is almost hidden beneath the bright red cloth covering it and the photographer. The message that photography was just child’s play may not have been what he intended, and wasn’t true at that time.

Paintings of photography seem to have peaked around 1870, when photographs were still relatively novel and unusual, and not perceived as much of a threat to the painter.

Philipp Sporrer’s The Photo (1870) is probably the most pointed painted propaganda. The young photographer is not the sort of man you would leave your wife or daughter with. He’s down at heel, unkempt, and his straw hat is abominably tatty. His studio is poorly-lit, probably an old shed, its floor littered with rubbish, and its window broken. His subject is manifestly poor and uncouth, sitting in ill-fitting clothes and picking his nose as he waits for the photographer to fiddle with his equipment.

Lajos Bruck’s The Photographer (1870) is perhaps fairer to the new medium, with a whole village and their innumerable children being cajoled into smiles ready for the camera. The itinerant photographer’s partner, though, seems disinterested, as she sits resting her head against her hand and looking away.

Pascal Dagnan-Bouveret’s A Wedding at the Photographer’s (1879) seems more calculated. Hugely successful at the Salon, this artist saw no threat from wedding photography, a market in which there was no competition between painting and photography. But he still takes the opportunity to show the photographer and his studio as being tatty and tawdry.

Gradually, painting started to become influenced by the nascent art of photography.

Gustave Caillebotte’s major painting of 1875 shows three workmen preparing a wooden floor in the artist’s studio at 77 rue de Miromesnil. It’s thoroughly detailed, Realist, and despite its innovative view and unusual subject, it conformed to the highest standards of the Salon at the time.

Caillebotte was hurt and angry when he was informed that this painting had been rejected by the Salon jury. The grounds given seem extraordinary now: apparently the jury was shocked at this depiction of the working class at work, and not even fully-clothed. It was deemed to have a ‘vulgar subject matter’ unsuitable for the public to view. Or was it really because of his wide-angle photographic effect?

Caillebotte was one of the first established painters to experiment with photography, as demonstrated in another wide-angle view of Paris Street, Rainy Day from 1877.

Soon, Thomas Eakins was using photographs to aid his painting.

His preparatory studies for Swimming (1885) grew from a series of photographs taken by the artist and his friends. But photos never replaced his own sketches: for this work, Eakins made several figure studies, details such as the dog, and different landscape backgrounds, and then brought them together in oil sketches.

Once he was happy, he embarked on his final version. In at least some cases, including his paintings of shad fishing from 1881-82, the figures in his Arcadia (c 1883), and Swimming (1885), he put final photographic images into a ‘magic lantern’ projector, which he then projected at the canvas.

He developed a sophisticated system not only for using the projected image to make a graphite underdrawing, but as the painting progressed, to incise key points and lines of reference in the paint surface. This enabled him to create paintings that were accurately calibrated to his reference images: a great advance on the traditional system of enlargement using grids, and one factor in his detailed realism. This technique was discovered by Mark Tucker and Nica Gutman.

Together with other photos and various studies, Eakins then painted Swimming (The Swimming Hole) in 1885.

Paul Louis Martin des Amoignes’ wonderful In the Classroom was painted the following year. It bears unmistakeable evidence that it was either painted from photographs or strongly influenced by them. One boy, staring intently at the teacher in front of the class, is caught crisply, pencil poised in his hand. Beyond him the crowd of heads becomes more blurred.

In Amsterdam, George Hendrik Breitner painted from photographs of his model Marie Jordan (1866-1948), whom he later married.

This photographic print of Marie Jordan Nude, Lying on the Bed from about 1888 is one of a series he made at about the same time that he was working on a painting of her.

Although conventionally dated to about 1887, there can be little doubt that Breitner’s Reclining Nude was based on that print.

Here are this weekend’s Mac riddles to entertain you through family time, shopping and recreation.

1: London to Pontarddulais in Macs for six months.

2: Jupiter’s flash now reaches 80 for the Pros.

3: Very long run from the Thames to Eastleigh came to the workshop in March.

To help you cross-check your solutions, or confuse you further, there’s a common factor between them.

I’ll post my solutions first thing on Monday morning.

Please don’t post your solutions as comments here: it spoils it for others.

With strong rumours that Apple intends changing its version numbering system for the next major release of macOS and its other operating systems, it’s a good time to see how we got to macOS 15.

Early Classic Mac OS

The first version of Classic Mac OS released with the original Macintosh 128K naturally came with System 1.0 and Finder 1.0. Within a few months, version numbering was already becoming confusing, when the successor System Software 0.1 had apparently started at 0.0, but the System itself had reached 1.1. This worsened when System Software 1.0 was released two years later, and came with System 3.1 and Finder 5.2.

Apple then adopted its first triplet numbering scheme that resembled modern Semantic Versioning in System 6.0 of June 1988. Over the following three years that worked its way steadily up to version 6.0.8, then handed over to System 7 on 13 May 1991 without any minor versions being released.

System 7

The first full use of the triplet numbering scheme came with System 7. That had four minor versions, 7.0, 7.1, 7.5 and 7.6, with each having patch releases such as 7.0.1 in between. This scheme followed the rules:

• the first number gives the major version;
• the second number gives the minor version that should remain backward-compatible in its changes;
• the third number gives the patch version denoting backward-compatible bug fixes.

It was then that Apple started to release special versions of Mac OS to support new models, for example 7.1P5 for Performa models, complicating the numbering. This was even worse with System 7.1.2, which was only supplied with some early Power Macs and a few 68K Quadra models. That was accompanied by System 7.1.2P, a special version for models released around the time that Apple also released System 7.5, in September 1994.

System 7.5 brought a different numbering scheme to deal with exceptions. For example:

• System 7.5.3 Revision 2 followed 7.5.3 without any Revision 1, and made various improvements;
• System 7.5.3 Revisions 2.1 and 2.2 were released on the same day to address problems with Revision 2 on different models;
• System 7.5.4 was never released at all, and the next release was 7.5.5.

Fortunately, the remaining versions of Classic Mac OS were conventional in their numbering, until the last in Mac OS 9.2.2 in December 2001.

Mac OS X

The public beta of Mac OS X introduced build numbers to supplement their triplet version numbering. At this time, the build number was based broadly on three components:

• the first number or build train gives the major version, starting from 4 for 10.0, as this includes NeXTSTEP up to version 3;
• the letter gives the minor version number, starting from A, which can also be bumped for hardware-specific builds, so may not match the triplet minor version number;
• the remaining number is the sequential build number within that minor version, usually incremented daily. That’s normally three digits, but an additional digit can be prefixed to indicate specific hardware platforms.

Triplet versions and build numbers were surprisingly well behaved until 2010, although separate build numbers were used during the transition from PowerPC to Intel architecture in Mac OS X 10.4 Tiger.

The first signs of complications came with Mac OS X 10.6.3, in March-April 2010, which came in three different builds and a v1.1, and 10.6.8 also had a v1.1 released a month after the original update. Mac OS X 10.7 Lion set a trend for a final Supplemental Update to 10.7.5, and frequent Security and Supplemental Updates became the rule by 2018, with macOS 10.12 Sierra and its successors.

By 2019, these updates had become uncontrollable. macOS 10.14 Mojave, for example, had three Supplemental Updates in the two months after its final release, named as 10.14.6 Supplemental Update, 10.14.6 Supplemental Update (a second time), and 10.14.6 Supplemental Update 2 (really 3).

macOS 11

The first version of macOS to support Apple silicon Macs, macOS 11 Big Sur, had been generally expected as macOS 10.16, but shortly before its announcement at WWDC in June 2020 the decision was made for it to become macOS 11, incrementing the major version number for the first time in almost 20 years. As that reset the minor version number from 15 to 0, there was the potential for chaos, as many scripts and much code had come to ignore the major version number, and to rely on the minor version to determine which release was running.

To cater for this, when those checked ProcessInfo.processInfo.operatingSystemVersion.minorVersion (or its equivalent), Big Sur identified itself as macOS 10.16. Apps ported to Xcode 12 used the 11.0 SDK; when they checked ProcessInfo.processInfo.operatingSystemVersion.minorVersion (or its equivalent), Big Sur identified itself as macOS 11.0. Those who relied on command tools were provided with a workaround, as
sw_vers -productVersion
returned 10.16 when running in Big Sur on an Intel Mac, but 11.0 on an Apple Silicon Mac.

This enabled Apple to return to a triplet scheme without the complications of Supplemental Updates or other vagaries. Each year’s major version of macOS has thus been x.0, with scheduled minor versions numbered from x.1 to x.5 or x.6, and intermediate patch releases (usually security updates) from x.x.1 upwards. At the end of its year as the current release of macOS, x.6 marked the start of its first year of security-only support, and x.7 for the second and final year. The exception to this has been Sonoma, which started its first year of security-only support with version 14.7, so its security updates have coincided in their minor and patch numbers with the older Ventura.

The only complication to this much clearer system was introduced in Ventura with Rapid Security Responses (RSRs). Those didn’t change the triplet version, as macOS proper remained unchanged, but added a letter to form, for example, macOS 13.4.1 (c). That proved clumsy, and when reflected in a resulting Safari version number it broke a lot of major websites that were unable to identify the browser version correctly. Since RSRs have fallen out of favour, this proved to be a passing phase.

When I wrote about the unexpected change in version numbering brought in Big Sur, I claimed that “no matter what Apple may eventually settle on, I shouldn’t have to change that again for many years.” I’m not sure that five counts as many, but here we go again.

References

Semantic Versions, SemVer
Apple package version numbering
Robservatory Mac OS X versions and release dates
System updates, including security data etc., since 2016

This is the summary and contents for the series titled Urban Revolutionaries showing paintings of the urban growth of the eighteenth and nineteenth centuries in Europe and North America.

The lure of city life was all about the promise of material goods and wealth, fine clothes, and smart carriages, all the things that were lacking in rural life. By 1780, Paris had trebled in size from that of the early fourteenth century, to reach a population of 650,000. Its accelerated growth during the nineteenth century saw it grow to 2.7 million in 1901. This was enabled by the agricultural and industrial revolutions.

Introduction

During these centuries, the majority of those who had farmed the country abandoned their homes and livelihoods for a fresh start in the growing cities. This Danish family group has just arrived in the centre of Copenhagen, and stick out like a sore thumb, with their farm dog and a large chest containing the family’s worldly goods.

1 Leaving the country

Those who arrived from the country found towns and cities to be alien places. Although many were extensively redeveloped during the nineteenth century, common people were often forced into cramped slums away from their grand buildings and streets, such as these tenements for immigrants in New York City.

2 Living in the city

Urban areas had to provide paid work, often in mills and factories. Towns grew rapidly across the coalfields of northern Europe as mines were sunk to extract coal, and again where iron ore was readily available.

3 Factories

Industry turned to coal to fuel its growth, and mining expanded in the coalfields across northern Europe. Industrial nations developed an insatiable need for young men to work as miners. In Britain alone, annual production of coal grew from 3 to 16 million tons between 1700 and 1815, and doubled again by the middle of the nineteenth century.

4 Coal and construction

Unrest grew among the workers in industrial towns and cities, leading to the Paris Commune of 1871, and a succession of strikes across Belgium in 1886. Those spread to other areas, resulting in violent confrontations between workers and the police and military.

5 On strike

Cities had plenty of inns and taverns where folk could consume alcoholic drinks until they couldn’t pay for them any more. While alcohol abuse also took place in the country, it was in the towns and cities that it became most obvious and destructive.

6 Demon drink

Women were widely engaged in light factory work, such as production of fabrics and garments by spinning, weaving and assembly. Many were also employed in domestic service industries including laundry and sewing, to service the middle and upper classes.

7 Women’s work

Prostitution was one of the most common ways for women to earn a living in the growing cities of Europe during the nineteenth century. Like bars and places of entertainment, it only thrived where there were plenty of potential customers with money, in cities like London and Paris.

8 The Oldest Profession

Few who migrated from the country ever made their fortune in the city, and most faced a constant battle to avoid poverty. Just as some social realists painted rural poverty in the middle of the nineteenth century, others depicted urban poverty.

9 Poverty

A few who migrated to the towns and cities did prosper. For young women, success could come through the growing world of fashion.

10 Rags to riches

As population density rose, so accommodation became crowded, the streets were often full of people, and vehicle traffic threatened the safety of pedestrians.

11 Crowds and traffic

As cities grew and swallowed up surrounding countryside, some substantial areas within them were retained as urban parks. But those who used them were overwhelmingly middle class, not the city’s workers.

12 Parks

Holidays were a privilege for the lower classes, and unpaid until legislation often as late as the twentieth century. Despite that, some workers saved all year and took a week’s unpaid leave to travel by railway to coastal and other resorts.

13 Holidays

Early cities were swept by epidemics of plague. In the nineteenth century, those were replaced by other communicable diseases including cholera, influenza and tuberculosis. Although improvements in sanitation brought cholera under control, epidemics continued to take their toll.

14 Epidemic

Although life in the country could be thoroughly miserable, stress of city life brought (and still brings) strain resulting from the stress of everyday life.

15 Angst

Next to the order of entries in the log, their date and time stamps are one of the most important pieces of information they contain. In some cases, such as when you’re using the log to estimate performance, their accuracy is vital. This article reports the results from tests to validate the times given in log records provided by the log show command, and in my free log browsers LogUI and Ulbow.

Clock date and time

Dates and times given in log extracts invariably match those of the Mac’s system clock, the only catch here being adjustments for time zone and DST. The latter can become confusing if you look at the log when DST is changed, or from a different time zone. To cope with that you can use the --timezone local option in log show to express all times with uniform adjustment. Ulbow doesn’t use that, but LogUI does now synchronise all time and date stamps to the current time zone and DST.

Time differences

The log is an excellent tool for measuring time and performance, either using regular entries or Signposts that are intended for the purpose. Writing an entry into the log incurs minimal overhead, and is simple to perform from any code or script. If your favourite scripting language doesn’t give direct access to writing entries, then you can use my free command tool blowhole to do so. If you want to assess processes in macOS, then it’s usually straightforward to identify appropriate milestones that mark events and use those to calculate the period. These all depend on the times reported in log entries being sufficiently accurate.

Gold standard

Since Mac OS X, every Mac has had a high-precision internal clock within it (prior to that Time Manager could resolve times down to the microsecond but no further). This increments monotonically in ‘ticks’, an unsigned 64-bit integer, starting from an arbitrary value, and is referred to as Mach Absolute Time (MAT).

Intel Macs increment their ‘tick’ count once every nanosecond, so the difference between two readings of the clock represents the time interval in nanoseconds. Life isn’t as simple with Apple silicon Macs, as they tick three times every 125 nanoseconds, or once every 41.67 nanoseconds. Apple’s latest documentation on MAT, its units and use, comes in a Technical Q&A dated 2005.

Once correctly converted into nanoseconds, MAT is the closest available measurement of time to a gold standard.

I suspect that log entries are originally given a raw MAT as their time, and that can be made available using the log show command, or in Ulbow, as that uses log show to obtain log entries. LogUI reads the log directly, through the OSLog API in macOS, which currently doesn’t provide MAT values, instead giving a lower resolution Date value.

This validation therefore compares time intervals given by Ulbow from log entry timestamps, and those given in LogUI, against MAT intervals obtained in Ulbow. To increase the challenge, log entries used are from blowhole writing 25 log entries as fast as it can, a worst case scenario as that writes 2-3 entries each microsecond.

Comparisons

Log extracts obtained using log show in Ulbow and those estimated by LogUI were compared, and their timestamps were found to be identical.

On an Apple silicon Mac (M4 Pro), entries written by blowhole had raw MAT values that recorded intervals of 9 or 10 ticks between them, after the first three were made 73 and 15 ticks apart. From the third of the series of 25 log entries there was a strong linear relationship between recorded MAT in nanoseconds elapsed and loop number, as shown in the chart below.

The gradient of the regressed line shows that blowhole‘s log entries occurred at intervals of just under 405 nanoseconds.

Because LogUI (and regular timestamps in log show and Ulbow) only resolve to microseconds, the matching plot for LogUI’s times against loop number is stepped.

The gradient of this regression line is 0.4, indicating that the intervals occurred at 400 nanoseconds, almost identical to that found for the MAT.

Plotting times measured by LogUI (which also represents those for Ulbow and log show, as they’re identical) against that of MAT shows a good linear relationship with a gradient of just under 1.009, indicating that timestamps in log show, Ulbow and LogUI are accurate and reliable estimates of MAT.

Differences between pairs of time estimates obtained from MAT and LogUI ranged from -83 to +792 nanoseconds, with a median of +370 and quartiles of +83 to +583 nanoseconds.

Conclusion

• Times given for log entries in LogUI, Ulbow and log show are reliable estimates of MAT to within +0.8 microseconds.
• When nanosecond resolution is needed, the machTimestamp field from log show or Ulbow should be used, and converted into nanoseconds.

In the days before contraception and family planning, when infant and child mortality were very high, many families had many babies and younger children, even though few would be expected to survive to have their own children. Households that could afford the space were able to dedicate rooms to the children, and sometimes their sheer number required it. This week’s paintings of interiors afford a glimpse at those central to the world of the child.

In the country, local schools were often held in a dedicated room in or adjacent to the teacher’s house, as seen in this undated painting by one of Eduard Ritter’s circle. Brave Girls, Bad Boys, School Class in Tyrol was probably painted between 1835-1849, during the reign of Emperor Ferdinand I of Austria who is shown in one of its portraits. The children are enjoying a rich range of fruit, and there’s no shortage of paper, even if some is being used to make hats rather than for writing. Its elderly schoolmaster looks delightfully benign, and the stem on his smoking pipe is the longest I have ever seen.

Pierre Olivier Joseph Coomans’ Children most probably dates from the late 1860s, with the artist’s two daughters Diana (1861-1952) and Héva (1860-1939) at play in the dark corner of a room. One is taking a swing at her sister’s articulated wooden doll in an apparent bid to continue dismembering it, the other is seated on an animal skin. Coomans’ daughters and a son all became successful painters.

Giuseppe Sciuti’s marvellous depiction of The Joys of the Good Mother, also known as The Geography Lesson, from 1877, shows three children from a close-knit family. The baby is feeding at mother’s breast, while the oldest is learning to read with her, and (with the assistance of a nurse in traditional dress) the middle child is learning about their country, Italy.

Lawrence Alma-Tadema and his wife Laura Theresa were both accomplished painters, and took delight in painting their two daughters from his first marriage, Anna (1864-1940) who also became a fine painter, and Laurense (1865-1940) who was a prolific novelist and poet.

Laura Theresa Alma-Tadema’s early painting of The Tea Party shows her step-daughter Laurense playing peacefully with her dolls in a corner of the girls’ room. Its walls are decorated with her drawings, and a comic-like story that may have been drawn by her step-mother.

Lawrence Alma-Tadema’s double portrait This is Our Corner from 1873 shows Anna in front of Laurense in their bedroom.

William Merritt Chase was also devoted to his family, and painted his children frequently as they grew up. However, if his Children Playing Parlor Croquet is correctly dated to about 1888, it must show the daughters of others. These two girls have taken over a room to play the indoor version of this game, which was popular at the time.

In 1889, Fritz von Uhde and his family were living in an apartment in the city of Munich, Germany, that was large enough to provide their three young daughters with The Nursery. The woman seen knitting at the right is likely to be a nanny or relative, as the artist’s wife had died three years earlier.

Helen Allingham’s undated In the Nursery shows a young woman employed as a nurse to a middle-class family, in their dedicated nursery. The fire has a guard, which would have been unusual in rooms used by adults. On the mantelpiece are what appear to be fans, probably part of the Japonisme that swept Europe and America during the late nineteenth century. Rocking chairs remain popular for helping infants and young children to sleep, of course.

It’s not clear whether the rather barren room shown in Georgios Jakobides’ Children’s Concert from 1894 is dedicated to these children. Given the cacophony they’re making with their musical instruments, it seems unlikely that any adult would want to be within earshot of them.

Searching for a file with a distinctive word in its name should be straightforward, but here I show some weird problems that could catch you out. I’m very grateful to Sam for drawing my attention to this, and welcome all and any rational explanations of what’s going on.

In some accounts of ancient Greek mythology, Cleta (Κλήτα) was one of the two Charites or Graces, alongside Phaenna. Her name apparently means renowned, and is still occasionally used as a first name today. It’s not the sort of word that should give Spotlight any cause for concern, and should prove easy to find.

Demonstration

To see the problems it can cause, create a folder somewhere accessible, in ~/Documents perhaps, and create half a dozen files with the names shown below.

Now open a new Finder window, and set it to Find mode using that command at the foot of the File menu. Then type into its search box the letters cleta

Only four of the files in that folder are found, excluding the first two, despite the fact that all their names clearly contain the search term.

Now clear the search box, and in the search criterion below, set it to find Name contains cleta, which you might have thought would be the same as the previous search.

Now all six files are found successfully.

You can try other variations of the file name to see which can be found using the search box, and which remain hidden. For example,
1995z_spectacletable_01.txt
also appears susceptible to this problem, suggesting that other examples might have the form
[digits]_[chars]cleta[chars]_[digits].[extension]

Separators

There are some other oddities at work as well, that you can see in the four file names that haven’t yet played hide and seek. So far I’ve been using Spotlight to find file names that simply contain the characters cleta. Now extend that to cletapainting

While you would expect the second of those to appear, Spotlight has elided the hyphen embedded in the first, as if it wasn’t there. Although Spotlight doesn’t provide a simple way to search for discrete words in file names, that’s a feature readily accessible in several third-party search utilities, including Find Any File and HoudahSpot. If you use Spotlight much, both of those are essentials, and you may wish to add Alfred as well.

As expected, Find Any File has no problems in finding all six test files when looking for names containing cleta

Set it to find names containing the word cleta, though, and it recognises spaces, hyphens and underscore _ characters as word separators, but doesn’t oblige with CamelCase, whether or not you capitalise its initial character.

Conclusions

• Avoid using the characters cleta in file names, as they can confuse Spotlight.
• Leave the search box in the Finder’s Find window empty and construct your search in the lower search bars instead.
• Spotlight can overlook hyphens in file names, but does treat them as word separators.
• Searching for words in file names can treat spaces, hyphens and underscore _ characters as word separators, but can’t cope with CamelCase.
• Spotlight’s rules are largely unwritten. Apple’s brief account is here, and doesn’t even mention the name Cleta.

My thanks again to Sam for providing me with the example of cleta that made this possible if apparently highly improbable.

Postscript

For those who think this all works as they expect, try the following file name:

1995z_star-post-office-cleta-hunt-portrait_01.txt

Towards the end of the nineteenth century narrative painters in Europe and North America followed the popular trend set by detective and mystery literary narrative, and produced paintings that:

• told a story previously unknown to the viewer, although they were likely to be familiar situations;
• intentionally didn’t resolve their narrative;
• deliberately offered several resolutions;
• often referred to contemporary moral and ethical concerns.

The only work for which William Frederick Yeames is now remembered, And when did you last see your Father?, painted in 1878, is unusual for its historical rather than contemporary setting, although its moral issues are timeless.

For anyone familiar with costume at the time of the English Civil War, and the Puritan dress of conical hats and plain clothes, this immediately places the event shown at that time. Contrasting with those are the opulent silks of the mother and children, who are clearly Royalists, the other side. Yeames tells us what the young boy is being questioned about in the painting’s title, without which the narrative would be largely lost.

The unresolved question is whether the boy did reveal the whereabouts of his Cavalier father, an act which is clearly bringing great anguish to his sisters and mother.

Hans Andersen Brendekilde’s Cowed from 1887 also requires careful reading that would have been considerably easier for viewers of the time. Superficially, it shows gleaners at work in a field after the harvest, but there’s more to its story than that.

Being gleaners, the figures seen are among the poorest of the poor. The owner of the large farm in the left distance has gathered in their grain, and their harvesters have been paid off for their effort. Then out come the losers, to scavenge what they can from the barren fields.

The family group in front of us consists of three generations: mother is still bent over, hard at work gleaning her handful of corn. Her husband is taking a short break, sitting on the sack in his large blue wooden clogs. Stood looking at him is their daughter, engaged in a serious conversation with her father, as her young child plays on the ground.

The daughter is finely dressed under her coarse gleaning apron, and wears a hat more appropriate to someone in service as a maid, or similar, in a rich household in the nearby town. She looks anxious and flushed. She may well be an unmarried mother, abandoned by her young child’s father, and it’s surely she who is oppressed or cowed. Their difficult family discussion is being watched by another young woman at the far left, who might be a younger sister, perhaps.

Yeames’ Defendant and Counsel, from 1895, was exhibited in London, illustrated as an engraving in newspapers, and so became the first mass-market painting of this kind.

It shows an affluent married woman wearing an expensive fur coat, sat with a popular ‘tabloid’ newspaper open in front of her, as a team of three barristers and their clerk look at her intensely, presumably waiting for her to speak.

As she must be the defendant, the viewer is encouraged to speculate what she is defending: a divorce claim, or a criminal charge? This also opens the thorny issue of counsel who discover that their defendant is lying, but still mount their defence in court, and may succeed in persuading the court to believe what they know to be false.

The press quickly seized on the ambiguities and oddities in Yeames’ picture. A critic in the upper-class newspaper The Times claimed that the painting was mistitled, and should have referred to the woman not as defendant, but as the respondent in a divorce case. They also questioned why the lawyers were still wigged and gowned when so obviously outside the courtroom, an issue the artist was forced to explain.

Yeames was besieged with inquiries from people who claimed they were unable to sleep because they couldn’t resolve the painting’s narrative. The following year, he agreed to judge the best explanation for one of his later paintings in The Golden Penny, a popular journal mainly about football, and had to wade through about seventy entries. It became clear that Yeames himself had little idea of the resolution of the story he’d painted, and awarded the prize to an account that didn’t actually resolve it at all.

While the chattering classes in Britain were puzzling over those paintings, the public in Spain were trying to resolve José Uría’s After a Strike, also from 1895. This story revolves around a strike and its violent consequence, and I have no supporting information about the artist’s intent.

The scene is a large forge that’s apparently standing idle because of a strike. At the far right is a row of mounted police or military, and what may be lifeless bodies laid out on the ground. Inside the factory a woman, presumably a wife, kneels and embraces her child, beside what is presumably the dead body of her husband, who was a worker there. Close to his body is a large hammer, apparently the instrument of his death. In the distance, one of two policemen comfort a younger woman.

This might show the tragic consequence of the violence resulting from a strike. Was the deceased trying to continue working when his colleagues had withdrawn their labour in a dispute, then came to blows with one of them, when he was struck and killed? Although in a sense the story has a form of resolution, it’s unclear how it got there, and invites speculation on the part of the viewer.

The most successful of all the British painters of problem pictures was John Collier, whose work reached a peak in The Sentence of Death in 1908.

At first, this disappointed the critics, but it quickly became enormously popular. Sadly the original work hasn’t lasted well, and I rely here on this contemporary reproduction that does it better justice.

A young middle-aged, and presumably family, man stares blankly at the viewer, having just been told by his doctor – visual clues given include a brass microscope and sphygmomanometer – that he is dying. The doctor appears disengaged, and is reading from a book, looking only vaguely in the direction of his doomed patient.

The late nineteenth and early twentieth centuries were a time of great advances in medicine, but the big killers in Europe and North America like tuberculosis remained common and barely affected by improvements in surgery and hospitals. In some ways, this painting may at the time have seemed quite everyday, but Collier’s genius was in confronting the viewer with mundane reality.

Not only did this problem picture tackle the great Victorian obsession with death and mortality, but it did so with an adult male patient, assumed by society to keep a ‘stiff upper lip’ and not to be emotional. This led to speculation as to the expected male response to such news, and questions as to what condition might be bringing about his death. There was even public debate about interpretations of the doctor-patient relationship.

Problem pictures lingered on in the early decades of the twentieth century, but were well past their peak.

William McGregor Paxton, a great admirer of Vermeer who adopted the Dutch master’s optical techniques, seems to have painted The Breakfast in 1911 as a ‘problem picture’. As their maid walks out of the dining room, a young wife stares thoughtfully away from her husband, who is showing no interest in her at all, as he hides behind the pages of a broadsheet newspaper. You could cut the atmosphere here with a knife, which is perhaps what this wife would like to do.

My final example is one that breaks the rule of this narrative not being known to the viewer, although in the case of Félix Vallotton’s Chaste Suzanne from 1922, that requires decoding of its carefully obscured reference to the Old Testament tale of Susanna and the Elders. Once that has clicked, you might presume this shows the two elders trying to blackmail Susanna into being unfaithful. But should we assume that Vallotton’s retelling ends in the same way as the ancient original?

Reference

Fletcher PM (2003) Narrating Modernity, the British Problem Picture 1895-1914, Ashgate. ISBN 978 0 754 63568 0.

A basic Mac system consists of the Mac itself and external storage for its backups, and is by far the most popular configuration. For many folk backing up the whole of its Data volume is wise, but that isn’t always the most economical. If the Data volume contains large items that don’t need to be backed up as often as its working folders, that can waste space. This article shows how you can make it more efficient without additional cost or hardware.

Backups and local snapshots

Most good backup utilities including Time Machine also make local snapshots of the volumes they back up. Let’s say your Data volume contains 100 GB of files that either change little or don’t need to be backed up as frequently as the rest. One proven strategy for minimising the time and storage required for backups is to add those to the exclusion list, and back them up separately, maybe only once a week. You can do that to another volume on external storage, provided you ensure there’s sufficient space for both that and your normal automatic backups.

What that doesn’t do is keep those 100 GB out of the frequent snapshots made of the Data volume. While you can exclude files and folders from backups, snapshots always include everything in that volume, without exclusions. The only way to save the space they add to snapshot size is to move them to another volume that doesn’t get snapshots made of it. But your Mac’s standard disk layout doesn’t provide any spare volume for that.

This could apply to all sorts of relatively static data that doesn’t need Time Machine’s automatic hourly backups, including Virtual Machines and some large media libraries, although you won’t then be able to share these in iCloud Drive, which would require them to be in your Data volume.

Boot disk layout

Standard layout of the internal SSD of an Apple silicon Mac running Sequoia or earlier is shown below.

Intel Macs have the same Apple APFS container with the Boot Volume Group in it, but the other two containers are replaced by a single small EFI partition.

Adding another partition or container is possible, but not recommended as it has a fixed size, and lacks the flexibility of a volume. It also risks disturbing the three existing partitions/containers. As they’re essential for the Mac to start up successfully, you don’t want to meddle with them.

In practice, the best place to add a new volume is inside the third container, the one already holding the System and Data volumes. Add that in Disk Utility once you’ve decided the next two steps.

Limit volume size

Your new volume is going to share space in its container with all the existing volumes, including both System and Data. It’s usually wise to impose a maximum limit on the size it can grow to, to avoid compromising any of those. When you add the new volume, put a sensible limit on its Quota Size.

Encryption

Although Apple’s documentation isn’t explicit, volumes added to the boot container aren’t protected by FileVault, unlike the Data volume. If you want your extra volume to be encrypted, you’ll have to format it in APFS (Encrypted). Whether that’s accelerated by the hardware in the Secure Enclave isn’t clear, and on Apple silicon Macs it’s hard to tell the difference, as you should get similar full speed performance from your extra volume to that of the Data volume.

Setting it up

Open Disk Utility, ensure its View options are set to Show All Devices, then select the Container holding the boot volumes. Click the + tool to add the new volume.

Give the volume a name, then click on the Size Options… button.

Enter your chosen Quota Size, as the maximum you want to allow the extra volume to use on the boot SSD, and click OK.

Then select whether you want it formatted in plain APFS, or encrypted, and click the Add button.

If you’ve opted for APFS (Encrypted) you’ll then be prompted to enter the encryption password. Unlike FileVault, there’s no option for a Recovery Key, or for iCloud Recovery.

When you first unlock the extra volume, you’ll be given the option to save its password to your keychain. That confirms this isn’t being performed by FileVault, as that protects its encryption keys in the Secure Enclave.

There are a couple of quirks:

• If you try unmounting the extra volume using the Finder’s contextual menu, macOS might try to unmount all volumes on the boot disk, and warn you that it can’t. Simply cancel those warnings, and the extra volume should unmount fine. If you’re worried by this, unmount the volume in Disk Utility, which isn’t as silly.
• You can use the Finder contextual menu to encrypt or decrypt the volume if you change your mind.

Summary

• To save space in local snapshots made for backups of your Data volume, move bulky items that you back up separately to an extra volume alongside the Data volume.
• Set a Quota Size on the extra volume to limit the maximum space it can take.
• Use plain APFS or APFS (Encrypted) as the extra volume can’t be protected by FileVault.
• If you encrypt the volume, safeguard its password as there’s no recovery option if you lose it.
• The extra volume performs as well as any other volume on the internal SSD, and is far faster than using external storage.

For many centuries if not a couple of millennia, narrative painting relied on depicting stories the viewer already knew, and knew the ending. Because painting a single synchronous image can only show one moment in time, most artists accepted that the viewer would have to set that into a narrative sequence in their mind. If they didn’t recognise the story, then the painting was lost on them.

Knowing the underlying story to a narrative painting is required for closure. Even the most skilled narrative painters like Nicolas Poussin were unable to achieve full closure in a painting alone. But without closure, the viewer would be left wondering and unsatisfied.

During the nineteenth century storytelling in literature changed. New genres such as detective and ‘mystery’ novels started to challenge the convention of narrative closure. Readers of Edgar Allan Poe’s short stories in the first half of the century, and Arthur Conan Doyle’s Sherlock Holmes novels towards the end, developed a taste for something rather different. In this week’s two articles about reading paintings I demonstrate how some of the finest problem pictures can be read.

As far as I can discover, one of the earliest major paintings lacking narrative closure is William Holman Hunt’s The Awakening Conscience, painted during the period 1851-53. As with most masterly narrative paintings, its story is assembled from the multitude of clues to be found in its image.

It shows a fashionable young man seated at a piano in a small if not cramped house in the leafy suburbs of London, in reality Saint John’s Wood. Half-risen from the man’s lap is a young woman who stares absently into the distance. They’re clearly a couple in an intimate relationship, but conspicuous by its absence is any wedding ring on the fourth finger of the woman’s left hand, at the focal point of the painting. Thus their relationship is extra-marital.

Around them are signs that she is a kept mistress with time on her hands. Her companion, a cat, is under the table, where it has caught a bird with a broken wing, a symbol of her plight. At the right edge is a tapestry to while away the hours, and her wools below form a tangled web in which she is entwined. On top of the gaudy upright piano is a clock. By the hem of her dress is her lover’s discarded glove, symbolising her ultimate fate when he discards her into prostitution. The room itself is decorated as gaudily as the piano, in poor taste.

The couple have been singing together from Thomas Moore’s Oft in the Stilly Night when she appears to have undergone a revelatory experience, causing her to rise. For Hunt this is associated with a verse from the Old Testament book of Proverbs: “As he that taketh away a garment in cold weather, so is he that singeth songs to an heavy heart.” Hunt leads us to imagine that this kept mistress has had a religious moment, seeing the route to her redemption as her conscience is awakened. The image brings hope, but without resolution.

Three years later, Philip Hermogenes Calderon exhibited Broken Vows (1856) at the Royal Academy, where the painting proved a great success, and remains his best-known work. It’s also the earliest true ‘problem picture’ I have come across, as it goes out of its way to encourage the viewer to speculate as to its reading.

A beautiful young woman, displaying her wedding ring, stands with her eyes closed, clutching a symbolic ‘heart’ area on her chest to indicate that her love life is in trouble. On the ground near the hem of her dress is a discarded necklace or ‘charm’ bracelet. The ivy-covered wall behind her would normally indicate lasting love, her aspiration.

A set of initials are carved on the fence, and on the other side a young man holds a small red flower in front of his forehead, which a young woman is trying to grasp with her right hand. The wooden fence appears tatty, and has holes in it indicating its more transient nature, and it provides glimpses of the couple behind.

Whereas clues in Holman Hunt’s The Awakening Conscience lead to consistent if unresolved narrative, Calderon has here deliberately introduced considerable ambiguity. The eyes of the shorter person behind the fence are carefully occluded, leaving their gender open to speculation. Most viewers are likely to conclude that the taller figure behind the fence is the unfaithful husband of the woman in front, but that requires making assumptions unsupported by visual clues. Whose vows are being broken? Calderon leaves us to speculate.

Edgar Allan Poe’s C. Auguste Dupin tales became highly popular across Europe when they were published from 1841 onwards, and in 1868 Émile Gaboriau’s serialised detective story Monsieur Lecoq shot to fame throughout France. That same year, Degas started work on his own detective story.

Degas’ Interior (1868-9), also known as The Interior and even The Rape, appears strongly narrative, but has so far defied all attempts to produce a reading consistent with its details.

A man and a woman are in a bedroom together. The woman is at the left, partly kneeling down, and facing away from the man. Her hair is cropped short, she wears a white shift which has dropped off her left shoulder, and her face is obscured in the dark. Her left forearm rests on a small stool or chair, over which is draped a dark brown cloak or coat. Her right hand rests against a wooden cabinet in front of her. She appears to be staring down towards the floor, off to the left.

The man stands at the far right, leaning against the inside of the bedroom door, and staring at the woman. He’s well dressed, with a black jacket, black waistcoat and mid-brown trousers. Both his hands are thrust into his trouser pockets, and his feet are apart. His top hat rests, upside down, on top of the cabinet on the other side of the room, just in front of the woman.

Between them, just behind the woman, is a small occasional table, on which there’s a table-lamp and a small open suitcase. Some of the contents of the suitcase rest over its edge. In front of it, on the table top, is a pair of scissors and other items which appear to be from a clothes repair kit or ‘housewife’.

The single bed is made up, and its cover isn’t ruffled, but it may possibly bear a bloodstain at the foot. At the foot of the bed, on its large arched frame, another item apparently of the woman’s clothing (perhaps a coat) hangs loosely. On that end of the bed is a woman’s dark hat with ribbons, and her corset has been dropped on the floor by the foot of the bed.

She clearly arrived in the room before the man, removed her outer clothing, and at some stage started to undress further, halting when she was down to her shift or chemise. Alternatively, she may have undressed completely, and at this moment have dressed again as far as her chemise.

The suitcase appears to belong to the woman; when she arrived, she placed it on the table, and opened it. This indicates that she was expecting to stay in the bedroom overnight, and brought a change of clothing and travelling kit including the housewife.

The man is obstructing the door, the only visible exit to the room. Although he looks as if he may have come no further across the room, his top hat says otherwise.

The man and woman appear to be a couple, who have met in that room to engage in a clandestine sexual relationship. However, the bed is a single not a double, and shows no sign of having been used, nor has the bedding been disturbed in any way. There is a mature fire burning in the fireplace behind the woman and the lamp.

There are four paintings or similar objects hanging on the walls, of which only one appears to be decipherable. This is the large rounded rectangular one above the fireplace. Although that appears to be a mirror, the image shown in it doesn’t resemble a reflection of the room’s interior, but looks to be a painting. This might show a bright figure, resembling the woman, in front of some shrubs, behind which are classical buildings. This doesn’t resemble any of Degas’ paintings, nor any well-known work.

Degas provides a lot of small details, just as in a detective story, none of which points clearly to a resolution. You can discuss and debate its narrative endlessly, as has been done for the last 150 years.

Berthold Woltze’s Der lästige Kavalier (1874), best rendered into English as The Annoying Bloke, is a fine example from a German specialist in the sub-genre.

The story takes place in a railway carriage, where there are two men and a young woman. She’s dressed completely in black, and stares towards the viewer with tears in her eyes (detail below). Beside her is a carpet-bag, and opposite is a small wooden box and grey drapes.

Leaning over the back of her seat, and leering at her, is a middle-aged dandy with a brash moustache and mutton-chop whiskers, brandishing a lit cigar. He appears to be trying to chat her up, entirely inappropriately and much against her wishes. Behind him, and almost cropped off the left edge of the canvas, is an older man with a dour, drawn face.

The young woman appears to have suffered a recent bereavement, and may even be travelling back after the funeral. She looks too young to have just buried a husband, so I think it more likely that she has just lost her last parent, and is now living alone, and prey to the likes of this annoying and abusive bloke. Woltze tackles a modern theme that became popular in ‘problem pictures’: relationships between men and women at a time when society was changing rapidly, and most particularly the changing roles of women.

My last example for today comes from the American genre artist Eastman Johnson at about the same time as Woltze’s encounter in the railway carriage.

Johnson’s painting only makes any sense when you know its title of Not at Home (c 1873), and apparently shows the interior of the artist’s home. Without those three words of the title, all you see is a well-lit and empty parlour, and the presumed mistress of the house starting up the stairs, in relative gloom in the foreground. At the right is a child’s push-chair, parked up and empty.

Those three words, of course, are the classic excuse offered in someone’s absence – “I am sorry, but the Mistress is not at home” – even when they are very much at home, but simply don’t want to see the visitor. So the title could imply that the woman is ascending the stairs in order not to see the visitor. Or, if we know that this is the artist’s home, could it be that it’s Johnson himself who is not at home?

Reference

Fletcher PM (2003) Narrating Modernity, the British Problem Picture 1895-1914, Ashgate. ISBN 978 0 754 63568 0.

Last week’s deep dive into the precision of times in the log concluded that, with the data currently available, the highest they can aspire to are microseconds, 10^-6 seconds, and not the nanoseconds given in the last build of LogUI. The aims of this new build are to deliver correctly rounded microsecond time resolution, and to adopt consistency in time zones and DST corrections.

I described in detail yesterday how I arrived at conversion of log entry dates to yield the time in microseconds. Here I’ll consider how to treat time zones correctly.

When you enter a start time in LogUI, this is assumed to be given in the local time set on your Mac, including both its time zone and any DST correction. LogUI already takes those into account, and performs any necessary adjustments.

Now that I have completely overhauled how LogUI converts the date stored for each log entry, I have changed behaviour in comparison with the default option of the log show command, and Ulbow that accepts its timestamps without question. The best way to see that is to observe log entries when the Mac’s time zone is changed.

Ulbow, and by default the log show command, uses date and time stamps adjusted for the time zone and DST setting at the time each entry is written to the log. You should therefore be prepared to see abrupt discontinuities in its timestamps. This condensed sequence of log entries from Ulbow shows what happens when you change time zone from New York to the UK during DST:
10:50:00.729672-0400 com.apple.Settings /AppleInternal/Library/BuildRoots/ … obfuscated() obfuscate output: …
10:50:00.729687-0400 com.apple.xpc.alarm Setting timer for "com.apple. …
15:50:00.730675+0100 === system wallclock time adjusted
15:50:00.730733+0100 com.apple.mobiletimer.logging … rescheduling 0 alarms
15:50:00.730754+0100 com.apple.xpc.alarm Setting timer for "com.apple.mdmclient.timer.ManualCertRenewalCheck" in 86080 seconds.

Instead, LogUI adjusts all log entries to the current time zone for consistency in reading:
15:50:00.729672+0100 com.apple.Settings /AppleInternal/Library/BuildRoots/ … obfuscated() obfuscate output: …
15:50:00.729687+0100 com.apple.xpc.alarm Setting timer for "com.apple. …
15:50:00.730675+0100 Boundary === system wallclock time adjusted
15:50:00.730733+0100 com.apple.mobiletimer.logging … rescheduling 0 alarms
15:50:00.730754+0100 com.apple.xpc.alarm Setting timer for "com.apple.mdmclient.timer.ManualCertRenewalCheck" in 86080 seconds.

If you’re using log show, you can add the --timezone local option to adopt the same behaviour.

This also solves the dilemma when you’re browsing the log through a time zone change, for example when the clock has gone forward to DST, or the reverse. In LogUI the rule is simple: enter the current time, and all log entries will be adjusted to and shown in that single time zone.

I’ve previously explained some of the confusion that can arise with DST changes, in the autumn/fall, and again in the Spring. Hopefully LogUI won’t lead to any confusion now.

LogUI 1.0 build 52 is now available from here: logui152
and from its Product Page.

Enjoy!

After telling of the death of Numa, King of Rome, Ovid continues his potted legendary history of Rome with a short series of strange events claimed to have occurred during its early period.

First, an Etruscan was ploughing his fields when one of the clods of earth was transformed into a prophet named Tages. Ovid then mentions the spear of Romulus being transformed into a tree on the top of the Palatine Hill. He moves on to the great early Roman general Cipus, who one day discovered he had grown horns on his head. He was invited to become King of Rome, but used a ploy to have himself banned from even entering the city. The Senate then gave him a plot of land outside the walls, commemorating his actions in a carving on the city’s nearby gate.

The major event during this period was the plague that struck Rome in 293 BCE, for which the god Aesculapius (Asclepius) was brought to the city.

When the oracle at Delphi was consulted, the Romans were told to seek the aid of the son of Apollo. Therefore the Roman Senate despatched a party to the port of Epidaurus in quest of Aesculapius, a son of Apollo. The envoy leading that mission had a dream one night, in which he saw Aesculapius beside his bed, holding a staff around which a snake was entwined. The god told the envoy that he would transform himself into a larger snake for the Romans to take back with them.

Sebastiano Ricci’s The Dream of Aesculapius (c 1718) shows the god clutching his staff with snake in his right hand, appearing in the Roman envoy’s dream at Epidaurus.

The following morning, the Romans gathered at the temple, where they saw a large golden snake, which the priest told them was the god Aesculapius. The snake promptly slithered down to the port where the Roman ships were berthed and boarded one of them, so the Roman party set sail to take it to Rome.

Ovid provides a long illustrated list of the places that they sailed past on their return journey, including a stop at Antium during bad weather. The ships finally sailed up the River Tiber to the city of Rome, where they were greeted by great crowds. The snake chose the island in the River Tiber for its home, and so ended the deadly epidemic that had killed many Romans.

Although Jules-Élie Delaunay’s The Plague of Rome (1869) is based on the account in Jacques de Voragine’s The Golden Legend, that in turn refers to Ovid’s story. A pair of good and bad angels appeared: the good angel then gave commands for people to die of the plague, and the bad angel carried those commands out. At the upper right edge of the canvas, an anachronistic white statue shows Aesculapius, who was to be the city’s salvation.

A drawing attributed to Jacques-Charles Bordier du Bignon, Aesculapius Routing Death (1822), also appears to have its roots in Rome’s plight. Aesculapius has two staffs with which he is despatching the grim reaper of death. The woman to the right of Aesculapius is thought to be the goddess Ceres, as she is pouring out her breast milk to feed the starving, a detail omitted from Ovid’s account.

There are also general representations of the god with his trademark serpentine staff, including Giovanni Battista Cipriani’s drawing of Aesculapius Holding a Staff Encircled by a Snake, completed before the artist’s death in 1785.

Johannes Zacharias Simon Prey painted this group of Aesculapius, Apollo and Hippocrates in 1791. Aesculapius, holding his distinctive rod, is shown in the centre of the trio, with Hippocrates, the rather less legendary ‘father of medicine’, to the right, clutching the basal half of a human skull, and Apollo, Aesculapius’ father, behind. Hippocrates’ mantle is trimmed with the Greek letters ΓΝΩΘΙ ΣΕΑΥΤΟΝ (gnothi seauton), “know thyself”, a maxim from the temple of Apollo at Delphi. They have entered a contemporary pharmacy, where an assistant uses a large mortar and pestle, and another works the bellows of a furnace. There are decorative and mischievous putti at play in the foreground.

Few traces remain of the temple of Aesculapius on Tiber Island, but Giovanni Battista Piranesi was able to find masonry that had formed a great stone ship complete with its decorated prow.

He shows this prow (above) in etchings made in 1756, and below in more detail. Carved into the rock is the unmistakable form of the serpent wound around Aesculapius’ rod, marking the site of the temple.

I hope that you enjoyed Saturday’s Mac Riddles, episode 309. Here are my solutions to them.

1: Glazed opening floats over desktop but not in the plural here.

Click for a solution

window

Glazed opening (a window) floats over desktop (windows do) but not in the plural here (no Windows, thank you).

2: Representative symbol venerated by the orthodox.

Click for a solution

icon

Representative symbol (an icon) venerated by the orthodox (they are).

3: À la carte bar to top it all with commands.

Click for a solution

menu

À la carte (an order from the menu) bar (what it is) to top it all (where it is) with commands (what it contains).

The common factor

Click for a solution

They’re the first three items in the WIMP human interface, although sometimes the M is taken as standing for mouse.

I look forward to your putting alternative cases.

Quite unintentionally, last week became a saga about time, and a good demonstration of how you should do your utmost to avoid working with it. This all started with an irksome problem in my new log browser LogUI.

LogUI departs from my previous log browsers in accessing log entries through the macOS API added in Catalina. When it first arrived, I found it opaque, and its documentation too incomplete to support coding a competitive browser at that time. Since then I have revisited this on several occasions, and each time retreated to using the log show command to obtain log extracts. As far as time is concerned, that presents me with two alternatives: a formatted string containing a date and timestamp down to the microsecond (10^-6 second), and a Mach timestamp giving the ‘ticks’ from an arbitrary start time.

Although the latter can only give relative time, the timestamp provided suffices for most purposes, and comes already formatted as
2025-05-25 07:51:05.200099+0100
for example.

Milliseconds

When you use the macOS API, date and time don’t come formatted, but are supplied as a Date, an opaque structure that can be formatted using a DateFormatter
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss.SSSZ"
let dateString = dateFormatter.string(from: date)
to provide
2025-05-24 13:46:12.683+0100

That only gives time down to the millisecond (10^-3 second), which is inadequate for many purposes. But changing the formatting string to "yyyy-MM-dd HH:mm:ss.SSSSSSZ"
just returns
2025-05-24 13:46:12.683000+0100
with zeroed microseconds. As I can’t find any documentation that states the expected time resolution of Dates, it’s unclear whether this is a bug or feature, but either way a different approach is needed to resolve time beyond milliseconds.

Nanoseconds

The only method I can see to recover higher precision in the macOS API is using DateComponents to provide nanoseconds (10^-9 second).
Calendar.current.component(.nanosecond, from: date)
returns an integer ready to format into a string using
nanosecStr = String(format: "%09d", nanoSeconds)
to give all nine digits.

Inserting that into a formatted date is a quick and simple way to construct what we want,
2025-05-24 13:46:12.683746842+0100
down to the nanosecond.

It’s only when you come to examine more closely whether the numbers returned as nanoseconds match changes seen in Mach timestamp, that you realise they’re a fiction, and what’s given as nanoseconds is in fact microseconds with numerical decoration.

Microseconds

The answer then is to round what’s given as nanoseconds to the nearest microsecond, which then matches what’s shown in Mach timestamps
let nanoSeconds = Int((Double(Calendar.current.component(.nanosecond, from: date))/1000.0).rounded())
and that can be converted into a string using
nanosecStr = String(format: "%06d", nanoSeconds)

Rather than manually format the rest of the date and timestamp, you can splice microseconds into the @ position of the format string
"yyyy-MM-dd HH:mm:ss.@Z"
turning
2025-05-24 13:46:12.@+0100
into
2025-05-24 13:46:12.683747+0100

Unfortunately, that’s too simple. If you test that method using times, you’ll discover disconcerting anomalies arising from the fact that seconds and microseconds are rounded differently. This is reflected in a sequence such as
2025-05-24 13:46:12.994142+0100
2025-05-24 13:46:13.999865+0100
2025-05-24 13:46:13.000183+0100
where the second rounds up to the next second even though the microseconds component hasn’t yet rounded up. The only way to address that is to format all the individual components in the string using DateComponents. And that leaves a further problem: how to get the time zone in standard format like +0100?

Time zones

Current time zone is available as an opaque TimeZone structure, obtained as
TimeZone.current
Note that this doesn’t need to be obtained individually for each Date, as its components are obtained using current Calendar settings, not those at the time the Date was set in that log entry. This should have the beneficial side-effect of unifying times to the same time zone and DST setting.

But that doesn’t offer it in a format like +0100, so that has to be calculated and formatted as
let timeZone = (TimeZone.current.secondsFromGMT())/36
let tzStr = String(format: "%+05d", timeZone)

Solution

The complete solution is thus:
let timeZone = (TimeZone.current.secondsFromGMT())/36
let tzStr = String(format: "%+05d", timeZone)
let dateComponents = Calendar.current.dateComponents([.year, .month, .day, .hour, .minute, .second, .nanosecond, from: date)
let yearStr = String(format: "%04d", dateComponents.year ?? 0)
let monthStr = String(format: "%02d", dateComponents.month ?? 0)
let dayStr = String(format: "%02d", dateComponents.day ?? 0)
let hourStr = String(format: "%02d", dateComponents.hour ?? 0)
let minuteStr = String(format: "%02d", dateComponents.minute ?? 0)
let secondStr = String(format: "%02d", dateComponents.second ?? 0)
let nanoSeconds = Int((Double(dateComponents.nanosecond ?? 0)/1000.0).rounded())
let nanosecStr = String(format: "%06d", nanoSeconds)
then concatenate those together with punctuation marks as separators to deliver the string
2025-05-24 13:46:12.683746+0100

If you’re coding in Swift, you might instead consider using Date.FormatStyle, although its documentation only refers to handling milliseconds, so I suspect that might turn out to be another wild goose chase.

If you know of a better way of handling this explicitly, don’t hesitate to let my code therapist know.

I have divided narrative forms in painting into the following categories:

• instantaneous, where the image is intended to show what was happening at a single moment in time, even though it’s likely to contain references to other moments in time;
• multi-image, where a series of separate images (paintings) is used to tell the story;
• multiplex, where a single image contains representations of two or more moments in time from a story;
• multi-frame, where two or more picture frames are used to tell a story, as in comics or manga;
• polymythic, where a single image contains two or more distinct stories.

The previous article showed examples of each apart from multiplex narrative, the subject of this sequel.

Multiplex

In more recent years, multiplex narrative has become considered by many narrative painters as being too complex for modern viewers. Given its popularity in ancient times and during the Renaissance, this appears curious.

Immediately on looking at this Roman painting of Perseus and Andromeda, you can see the duplicated images of Perseus: one flying in from the left, the other being congratulated at the right. If intended to be a literal telling of the story, Cetus the sea monster wouldn’t appear until after Perseus had freed Andromeda from her chains. It therefore contains at least two different moments in time, but isn’t divided into frames, and is therefore multiplex narrative.

Masaccio’s fresco in the Brancacci Chapel of The Tribute Money (1425-8) contains three images of Saint Peter, and two of the tax gatherer, carefully set and projected into the same single view. Although each is spaced apart from the next, no pictorial device is used to separate them into frames.

His literary reference is to the Gospel of Matthew, in a story in which Christ directs Peter to find a coin in the mouth of a fish so that he can pay the temple tax. In the centre, the tax collector asks Christ for the temple tax. At the far left, as indicated by Christ and Peter’s arms, Peter (shown a second time) takes the coin out of the mouth of a fish. At the right, Peter (a third time) pays the tax collector (shown a second time) his due.

Masaccio demonstrates how important space and layout are in successful multiplex narrative.

In Piero di Cosimo’s Andromeda freed by Perseus (c 1510-15), Perseus appears three times: flying down from the top, stood on Cetus about to kill the monster, and in the subsequent party at the bottom right. Andromeda also appears at least twice. These separate events are combined in its multiplex narrative.

The five different sets of Adam and Eve shown in Lucas Cranach the Elder’s The Garden of Eden (1530) are set within the representation of the garden as a whole, making this multiplex narrative.

Following the Renaissance, multiplex narrative was largely forgotten, until its more recent revival.

At the centre of Camille Corot’s painting, Diana and her attendant nymphs are bathing in a stream, and soaking up the sunshine. At the right, Actaeon with one of his hunting dogs is just about to run straight into them. Diana, appropriately crowned, stands pointing to the distant figure at the left, which is again Actaeon, antlers growing from his head as she transforms him into a stag.

Actaeon appears twice in spatially separate scenes, with Diana and her group being part of both. In the first, they are simply bathing and larking about, but in the second Diana stands, points, and transforms Actaeon.

In the early twentieth century, Lovis Corinth’s Ariadne on Naxos (1913) combines two separate events into a single image: the abandonment of Ariadne by Theseus on the left, and the arrival of Dionysus/Bacchus to be her future husband on the right. He does this without any duplication of actors, and it’s multiplex narrative.

At the centre of Thomas Hart Benton’s Achelous and Hercules from 1947 is Hercules, stripped to the waist and wearing denim jeans, who is about to grasp the horns of Achelous, shown in the form of a bull. Immediately to the right, Deianira is shown in contemporary American form, with a young woman next to her bearing a laurel crown and seated on the Horn of Plenty. To the left of centre, Benton shows a second figure of Hercules holding a rope, part of a passage referring to ranching and cowboys, and further to the left to the grain harvest. To the right, the Horn of Plenty links into the cultivation of maize (corn), the other major crop from the area.

This narrative technique is by no means confined to Europe, as shown in the next two examples.

This detail of Krishna Storms the Citadel of Narakasura (c 1840) contains two near-identical representations of Krishna, making it multiplex narrative.

My final example of multiplex narrative is that of the Heiji Monogatari Emaki (Sanjo Scroll) (late 1200s), in which time advances from right to left, and there is duplication of actors.

Of all the features of our Macs, the one we most take for granted must be time. From the moment it starts up, we expect its clocks and timekeeping to be accurate, whether it’s the clock at the far right of the menu bar, or times recorded in its logs. This article explains how to ensure that works, and what to do when it doesn’t.

Settings

Unless your Mac is one of the few that isn’t connected to the Internet, set it to check time and clocks by syncing with Apple’s Time Server over the network. Standard settings for doing that are located in the Date & Time section of General settings.

Time and date are set automatically using time.apple.com as the source, and where possible the time zone is set automatically using your Mac’s current location.

In some cases, a local network time server may be preferred by setting the source to a different network address. This can be useful within active local networks, where it’s important that all network devices are synchronised to the same source, although that should work just as well using Apple’s time service. Some computers allow you to specify multiple time servers, in case some of them aren’t reachable. macOS only uses one, and if you do provide a list of NTP servers, only the first will be used.

The most common problem arises when the time zone can’t be set automatically using Location Services. This is buried more deeply, in Location Services in Privacy & Security settings. Click on System Services, and ensure you have allowed access to Setting time zone, and that Location Services is enabled.

One common situation where this doesn’t work is in Virtual Machines, which normally aren’t able to get an accurate location as they can’t access Wi-Fi directly. You’ll then have to set the time zone manually.

Like daylight savings or summer time, time zones don’t change the time of the system clock, but are corrections applied to times read from that and presented in localised form for you to see.

Importance

Accurate system clock time is of considerable importance in many respects, as it’s used for the timestamps of files and directories, and can have implications for security. APFS uses transaction identifiers (XIDs) to keep track of the order of events within its file systems, so isn’t reliant on timestamps, but other features may not have such an independent mechanism. Backups are an obvious example, where decisions can be confused by contradictory file creation and modification times.

Sometimes users deliberately change the system clock and disable its online updates to run a Mac using past time, for example to work around an expired security certificate. Although that may work well at the time, it can lead to strange problems resulting from disordered time sequences, and should be used with caution.

NTP service

Accurate and synchronised time has been required since long before the Internet, and is available using other means. Navigation and other systems have been using radio time signals for many decades, and most recently GPS satellites provide highly precise time. The disadvantage to these is that they require special radio receivers that aren’t built into Macs, although most of Apple’s devices now include GPS receivers. Another way to get accurate time is from a local atomic clock, but they’re beyond our budget.

The alternative is an NTP server like time.apple.com, but that poses another problem, as the server has to be polled over the network, and that takes time in both directions. To account for that, macOS has to calculate a time offset as the difference in absolute time between its clock and that of the NTP server, and the round-trip delay for the whole request. It can then estimate how much it needs to adjust the Mac’s clock time to be in sync with the server.

Because time offset and round-trip delay vary in each check with a server, macOS may perform several checks and use those to derive best estimates.

One important confounding factor here is anything that leads to long delays in connecting with the NTP server, and the most common cause of those is using a VPN service. Routing NTP connections through your VPN service can cause inaccurate local clock times.

timed

As far as I’m aware, prior to macOS 10.13 High Sierra, macOS used an ordinary NTP client to connect to NTP servers and correct its clock time. Apple then replaced that with a new and proprietary service timed, described thus:
timed maintains system clock accuracy by synchronizing the clock with reference clocks via technologies like NTP. Inputs are merged inside of timed, where it calculates uncertainty to facilitate scheduling proactive time jobs. timed is also aware of power/battery conditions.

This is run as a LaunchDaemon, found at /System/Library/LaunchDaemons/com.apple.timed.plist. The time server used is set in /etc/ntp.conf, and is normally time.apple.com. timed relies on three property lists in a locked-down directory /var/db/timed/. These are:

• com.apple.timed.plist containing its cached state, with values for TMLastNtpFetchAttempt, TMLastRtcTime, TMSystemTimeSet and more, and binary data for STF and TDTF;
• Library/Preferences/com.apple.preferences.datetime.plist with a single key-value pair for timezoneset, which should be true;
• Library/Preferences/com.apple.timed.plist with two key-value pairs for NtpUseServicePort and TMAutomaticTimeOnlyEnabled, both set to true.

SNTP

macOS 11.0 Big Sur brought two additions to support basic SNTP:

• sntp is a simple NTP client claimed to be able to set or slew the system clock if it’s out of sync;
• sntpd is a basic SNTP server daemon that can be launched through /System/Library/LaunchDaemons/com.apple.sntpd.plist, and stores header data in /var/sntpd/state.bin.

Neither appears to be run or used routinely in macOS, as it prefers to handle this through timed and the com.apple.timed subsystem.

It’s sometimes suggested to use sntp to adjust the system clock using the command
sudo sntp -sS time.apple.com
Although this runs and reports offsets from the NTP server, it requires sudo if it’s to perform clock adjustments using adjtime, and it’s not clear what effect it has on timed.

Log

timed and clock adjustment occurs relatively late during the boot process, as it requires timed to be running with access to network connections. However, you may be confused by a pair of prominent Boundary entries that appear before synchronisation:
02.452702045 Boundary === system wallclock time adjusted
02.524229049 Boundary === system wallclock time adjusted
where the initial system boot entry was made at 00.0 seconds. Those are only internal adjustments.

timed and com.apple.timed subsystem start entries after those, first giving the version and build of timed, then announcing its start
02.741880893 com.apple.timed cmd,start

timed‘s cached state is then read from disk, and TMTimeSynthesizer is used to set system time
03.421952009 com.apple.timed Setting system time to Tue May 20 08:24:04 2025 from TMTimeSynthesizer

Initially, without a network connection, timed has to wait to sync with the NTP server
03.476943969 com.apple.timed We want time and don't have network! Keeping timed alive until network comes up, since we are beyond our wanted threshold.

Eventually, the NTP server is reachable
04.200660943 com.apple.timed Fetching NTP time.
04.249860048 com.apple.timed Received time Tue May 20 08:24:05 2025±0.01 from "NTP"

Another three time estimates are obtained from APNS
07.982021093 com.apple.timed Received time Tue May 20 08:24:09 2025±35.00 from "APNS"
13.667812108 com.apple.timed Received time Tue May 20 08:24:14 2025±35.00 from "APNS"
14.488466024 com.apple.timed Received time Tue May 20 08:24:15 2025±35.00 from "APNS"
leading to adjustments to system time. I don’t think that the APNS referred to here is Apple Push Notification Service, could it be Apple Primary Name Server, perhaps?

Slower is better

As a general principle, correcting the clock backwards to an earlier time would be bad news, as it would confuse anything that relies on time order. This can be seen, for example, in the autumn/fall when daylight savings or summer time ends in many countries, and localised clocks are set back in time. This ensures that for a period of roughly an hour, localised times duplicate those from the previous hour, and is particularly difficult to handle in log extracts.

If the system clock is going to err, then it’s better for it to be slightly slow, which allows adjustments forward in time that can’t result in duplication of timestamps.

Summary

• Unless your Mac isn’t connected to the Internet, set its time and date automatically using time.apple.com as the source, and enable it to set its time zone automatically through Location Services.
• Virtual Machines that can’t use automatic time zone settings should have their time zone set manually.
• A local network time server may be a preferred source, but macOS will only use one NTP server.
• Deliberately backdating a Mac’s clock can have untoward effects, and should be used with caution.
• Use of a VPN can delay syncing with the NTP server, and can cause clock problems.
• From macOS 10.13, macOS relies on timed to sync time.
• Using sntp to force sync clock corrections is still available, although it isn’t clear whether it’s effective.
• Trace timed activity in the log using the subsystem com.apple.timed.

References

NTP in Wikipedia

Apple has just released an update to XProtect for all supported versions of macOS, bringing it to version 5298. As usual, Apple doesn’t release information about what security issues this update might add or change.

This version adds new rules for MACOS.ADLOAD.CODEP, MACOS.ADLOAD.BYTE.B and MACOS.PIRRIT.OP.OBF, and amends the rule for MACOS.PIRRIT.BM.OBF.

You can check whether this update has been installed by opening System Information via About This Mac, and selecting the Installations item under Software.

A full listing of security data file versions is given by SilentKnight and SystHist for El Capitan to Sequoia available from their product page. If your Mac hasn’t yet installed this update, you can force it using SilentKnight or at the command line.

If you want to install this as a named update in SilentKnight, its label is XProtectPlistConfigData_10_15-5298.

Sequoia systems only

This update has already been released for Sequoia via iCloud. If you want to check it manually, use the Terminal command
sudo xprotect check
then enter your admin password. If that returns version 5298 but your Mac still reports an older version is installed, you may be able to force the update using
sudo xprotect update

I have updated the reference pages here which are accessed directly from LockRattler 4.2 and later using its Check blog button.

Telling a story, narrative, in a painting is one of its most common purposes, and greatest challenges. A landscape painting shows a view at a moment in time, but doesn’t normally tell a story, as that requires a minimum of two states, with the story linking them. So, although we might speculate what’s going in that countryside, without an indication of what went before, or what happened afterwards, there’s no story there.

Over the centuries, even millennia, since humans have been painting, several techniques have developed for telling a story with more than one timepoint shown in paintings. Although the terms used have varied, in general those fall into the following categories:

• instantaneous, where the image is intended to show what was happening at a single moment in time, even though it’s likely to contain references to other moments in time;
• multi-image, where a series of separate images (paintings) is used to tell the story;
• multiplex, where a single image contains representations of two or more moments in time from a story;
• multi-frame, where two or more picture frames are used to tell a story, as in comics or manga;
• polymythic, where a single image contains two or more distinct stories.

In this article and tomorrow’s sequel, I show examples of each of these.

Instantaneous

Nicolas Poussin’s Rinaldo and Armida from about 1630 draws its narrative from one of his favourite literary works, a then-popular epic poem by Torquato Tasso (1544-1595) titled Gerusalemme Liberata (Jerusalem Delivered), and published in 1581. I have written a series of fourteen articles showing paintings and telling its story, which start here. This particular episode is detailed here.

The sleeping knight is Rinaldo, the greatest of the Christian knights engaged in Tasso’s romanticised and largely fictional account of the First Crusade, who has stopped to rest near the ‘ford of the Orontes’. On hearing a woman singing, he goes to the river, where he catches sight of Armida swimming naked.

Armida, though, had an evil aim, in that she had been secretly following Rinaldo, intending to murder him with her dagger. As the ‘Saracen’ witch who is trying to destroy the crusaders’ campaign, she had singled out its greatest knight for this fate. Having revealed herself to him, she sings and lulls him into an enchanted sleep so that she can thrust her dagger home.

Just as she is about to do this, she falls in love with him instead, and that’s the instant, the twist or peripeteia (to use Aristotle’s term), shown here. A winged amorino, lacking the bow and arrows of a true Cupid, restrains her right arm bearing her weapon. Her facial expression and left hand reveal her new intent to enchant and abduct him in her chariot, so he can become infatuated with her, and forget the Crusade altogether.

This is a single moment in time, in which Poussin has ingeniously incorporated references to the past and future. Provided that you’re familiar with Tasso’s story, it’s a superb example of instantaneous narrative, as practised throughout the history of painting across all continents and cultures.

Jean-Léon Gérôme’s Cleopatra before Caesar (1866) also depicts a single instant, but again has references to prior events, particularly the screwed up carpet, used by Cleopatra to gain entry. Her dreamy look towards Caesar also anticipates her affair with him. It therefore has instantaneous narrative.

Sometimes paintings with instantaneous narrative can make quite small and subtle references to other events in the story, and confirm their narrative nature. In Edward Burne-Jones’s Cinderella (1863) the only such reference is the missing slipper on Cinderella’s right foot.

Although Édouard Detaille’s Le Rêve (The Dream) (1888) contains two images, these aren’t in fact linked by normal narrative, but the dream image shown in the clouds could be considered as a form of analepsis, or flashback, making it instantaneous narrative.

Multi-image

I’ll be brief with these, as I have covered more examples here and here.

In 1856, Arthur Hughes told the story of The Eve of St Agnes in this triptych, read from left to right. At the left Porphyro is approaching the castle. In the centre he has woken Madeline, who hasn’t yet taken him into her bed. At the right the couple make their escape over drunken revellers.

Akseli Gallen-Kallela’s triptych showing the Aino Myth (1891) contains three separate images telling one of the stories from the Kalevala myths. It is therefore multi-image narrative, within which each image is itself conventional instantaneous narrative.

Multi-frame

Multi-frame paintings are by no means uncommon, but most usually adopt rectangular or square form. Indeed many of the more spectacular frescoes are in effect multi-framed, where there are several images on a single continuous surface. This is similar to the more recent development of comics/BD/graphic novels.

Gaudenzio Ferrari’s Stories of The Life and Passion of Christ (1513) arranges twenty frames covering the life of Christ around a central frame with four times the area of the others, showing the Crucifixion. The frames are naturally (for the European) read from left to right, along the rows from top to bottom, although the Crucifixion is part of the bottom row. This is a layout which is commonly used throughout graphic novels too, of course, and is a superb example of multi-frame narrative more than three centuries before Rodolphe Töpffer started experimenting with comic form.

The four separate episodes forming Hans Sebald Beham’s Scenes from the Life of David (1534) are arranged in a square, so that each occupies a triangular frame, clearly separated from the others, and quite different from a normal linear layout. The snag with this is that the panel is really only suitable for viewing when laid flat on a table, otherwise only one of the frames is correctly orientated. Beham clearly liked the symmetry afforded by this layout, and enhanced it in his composition of the two frames shown here at the top and bottom.

Frans Francken the Younger’s The Crucifixion of Christ, with Scenes from the Life of Jesus (1600s) puts the Crucifixion scene at the centre of a rectangle, around which are twelve scenes from the life painted in either normal or brown grisaille. Unfortunately those peripheral scenes are difficult to differentiate from one another, thus to identify, but they appear to be read in a clockwise direction from the upper right, rather than linearly.

Polymythic

Although linked, and often told together, the stories of Echo and of Narcissus can be separated, and it’s therefore feasible to classify John William Waterhouse’s Echo and Narcissus (1903) as being unusual in showing polymythic narrative.

A few paintings appear even more complex: Velázquez’s Las Hilanderas (The Spinners) may contain one narrative in the foreground, a second in the background, and a third in the painting of The Rape of Europa shown in the far background. This would make it polymythic narrative at the very least.

Now we’ve got LogUI to give us the times of log entries down to the nearest nanosecond, it’s time to see whether that’s any improvement over other tools. Given that Mach Absolute Time resolves to nanoseconds (10^-9 seconds) in Intel Macs, and just under 42 nanoseconds in Apple silicon Macs, can we now resolve times of events better than when using microseconds (10^-6 seconds)?

Methods

To test this out, I used my command tool blowhole that can run a tight loop writing entries in the log as fast as possible. To do this, it uses the code
for index in 1...number {
os_log("%d", log: Blowhole.gen_log, type: type, index)
}

I then wrote loops of 20 to the log of an iMac Pro (Intel Xeon W CPU), M3 Pro and M4 Pro, and extracted the resulting log entries using LogUI with its new nanosecond times.

Results

Plotting these times against loop number resulted in unexpected patterns.

In this graph, results from the iMac Pro are shown in black, those from the M3 Pro in blue, and the M4 Pro in red. Although less well-ordered in the first to fourth loops, from the fifth loop onwards there were linear relationships between time of log entries and loop number. Linear regression equations are shown in the legend, and demonstrate:

• on the iMac Pro each loop takes 1.0 x 10^-6 seconds, i.e. 1 μs;
• on the M3 Pro each loop takes 5.6 x 10^-7 seconds, i.e. 0.6 μs;
• on the M4 Pro each loop takes 4.6 x 10^-7 seconds, i.e. 0.5 μs.

which perhaps isn’t surprising.

However, the patterns of individual points are quite different. Apart from loops 4 and 5, subsequent loops on the iMac Pro are evenly spaced in time. Those on the Apple silicon chips are grouped in pairs or, for loops 14-16 on the M4 Pro, in a triplet, where two or three loops are assigned the same time in the log.

Looking at time differences, a clear pattern emerges, that log times are incremented in steps of 954 ns. For the iMac Pro, each loop occurs one step later, while for the M3 Pro and M4 Pro steps between pairs and triplets are also 954 ns. In a few cases, the step difference is slightly greater at around 1192 ns instead of 954 ns. Apple silicon chips are faster on average because each step includes two or more loops, while the iMac Pro only manages one loop per step.

Explanation

If log entry times had been given in microseconds rather than nanoseconds, the same patterns would have been seen. But without the additional precision in their times, it wouldn’t have been clear that multiple log entries were being written with identical times, down to the nanosecond.

One likely explanation is that macOS only writes log entries approximately every microsecond, and the entry time recorded for each is that of that writing. Writing log entries must occur asynchronously for the M3 Pro and M4 Pro to be able to send pairs or triplets to be written, rather than having to wait for each writing process to complete.

Thus, the time resolution of log entries is approximately 1 μs, or 954 or 1192 ns to be more precise, and that’s the same regardless of whether macOS is running on a recent Intel Mac or the latest Apple silicon chips. Although a time resolution of 1 μs is sufficient for general purposes, if you want to dig deeper, as I have done here, access to the finer resolution provided in nanosecond times is essential.

Conclusions

• Times written in log entries are incremented every 954 or 1192 ns on both Intel and Apple silicon.
• Faster Apple silicon chips can write more than one entry in the same time increment.
• Although expressing the time of log entries in microseconds is sufficient for general purposes, using nanoseconds can confirm which have occurred simultaneously.

The Music of Time

So what is a Dance to the Music of Time? It’s one of Nicolas Poussin’s most brilliant paintings, that inspired a series of twelve novels written by Anthony Powell. While I wouldn’t attempt to summarise those, here’s the painting to enjoy.

Poussin’s Dance to the Music of Time (c 1634-6) shows four young people dancing, who are currently believed to be Poverty (male at the back, facing away), Labour (closest to Time and looking at him), Wealth (in golden skirt and sandals, also looking at Time), and Pleasure (blue and red clothes) who fixes the viewer with a very knowing smile. Opposite Pleasure is a small herm of Janus, whose two faces look to the past and the future. Father Time at the right is playing his lyre to provide the music, and an infant seated by him holds a sandglass, to measure time periods. Above them in the heavens, Aurora (goddess of the dawn) precedes Apollo’s sun chariot, on which the large ring represents the Zodiac, thus the passage of the months. Behind the chariot are the Horai, the four seasons of the year.

Ovid’s fifteenth and final book of his Metamorphoses continues his account of the early rulers of Rome, making its way steadily to reach the Emperor Augustus. Following the apotheosis of Romulus, the next to feature is his successor Numa, who becomes the narrator for an overview of the Metamorphoses in terms of Pythagorean philosophy.

Fame nominates Numa as successor to Romulus as the ruler of Rome. Numa had left Cures, the town of his birth, to travel to Crotona (Crotone), in the far south of the Italian peninsula, where he visited Croton, its ruler.

This is the cue for a story about Myscelus, who founded Crotona. Hercules appeared to him in a dream, and told him to travel to the river Aesar, despite his being forbidden from leaving his native land of Argos. Driven by dreams of Hercules, Myscelus tried to leave but was accused of treason, and appealed to Hercules to save him from the mandatory death penalty. At that time, trial juries voted by casting black or white pebbles into an urn; being undoubtedly guilty, all those cast in Myscelus’ case were black when they were placed in the urn. But when the urn was emptied they had all changed to white, and Myscelus was saved, and able to sail to found Crotona on the River Aesar.

After he had fled Samos, Ovid tells us that Pythagoras lived in exile at Crotona, and this leads to a long discourse on his doctrines and philosophy. Having assured us of Pythagoras’ diligent observation of the world around him and careful analysis of what he saw, Ovid starts with an exhortation to vegetarianism.

Within this discourse, Ovid makes reference to preceding sections and themes of Metamorphoses. Pythagoras’ words hark back to the Golden Age covered in the first book. Pythagoras lays claim to reincarnation too, saying that in a previous life he had been Euphorbus, who had been killed by Menelaus in the Trojan War. This leads Pythagoras to discussing change and transformation, the central theme of these fifteen books.

Pythagoras sees change in the waves of the sea, in the sequence of day and night, in the four seasons, in the ageing of humans, and in the transformation of the elements (earth, air, water, and fire).

Pythagoras then illustrates this constant change with a long list of places whose geography had changed in recorded history, and of places that cause change in those who visit them. After those, he returns to the theme of change in animals, telling the legend of the Phoenix reborn from the ashes of its parent. This leads on to consideration of some great cities that have fallen, and the chance to point out that Troy never fell completely, as it reached its destiny of founding the city and empire of Rome. Pythagoras concludes by exhorting vegetarianism by looking for harmless food rather than killing other animals.

In his magnificant fresco in the Palazzo Apostolico, The School of Athens painted in about 1509-11, Raphael includes Pythagoras at the lower left corner.

This detail shows Pythagoras writing in a large book, with a chalk drawing on a small blackboard in front of his left foot. Others are looking over his shoulder and studying what he is doing.

Peter Paul Rubens collaborated with Frans Snyders to paint Pythagoras Advocating Vegetarianism in about 1618-20. The mathematician and philosopher sits to the left of centre, with a group of followers further to the left. The painting is dominated by its extensive display of fruit and vegetables, which is being augmented by three nymphs and two satyrs. One of the latter seems less interested in the food than he is in one of the nymphs.

Today, Pythagoras is best known for his geometric discoveries, rather than the doctrines detailed by Ovid. Fyodor Bronnikov’s painting of Pythagoreans Celebrate Sunrise from 1869 is perhaps more in keeping with the Classical perception. These followers are decidedly musical, holding between them four lyres, a harp, and a flute, and worshipping the rising sun.

After Numa had learned the doctrines of Pythagoras (an historical impossibility, as Numa lived between about 753-673 BCE, and Pythagoras between about 570-495 BCE and lived in Croton from about 530 BCE), he returned to Rome and established its early laws and institutions.

Numa’s success depended on his wife, the nymph Egeria. Although Ovid isn’t explicit, other sources make the couple’s meeting a key step in the development of Rome, as Egeria was said to have dictated the first set of laws of Rome to Numa.

Nicolas Poussin’s Numa Pompilius and the Nymph Egeria from 1631-33 is thought to have been painted for his long-term friend and patron Cassiano Dal Pozzo (1588-1657), a scholar and patron of the arts, who was secretary to Cardinal Francesco Barberini.

It shows the meeting of King Numa, at the right, with Egeria, at the left, as she was being entertained by a young man with a lute, who may signify the Muses who apparently inspired Egeria to provide the laws of Rome. However, Numa hasn’t come equipped with any means of recording them, suggesting that this wasn’t the occasion on which Egeria dictated those laws.

Felice Giani’s much later painting of Numa Pompilius Receiving from the Nymph Egeria the Laws of Rome (1806) shows that process of dictation in full swing, with Numa working through scrolls, which are then transcribed onto the tablets of stone seen at the left. The nymph is the one sat on a throne, and is clearly in command, wagging her index finger at the King of Rome.

Ulpiano Checa’s The Nymph Egeria Dictating to Numa Pompilius the Laws of Rome (c 1886) offers a similar account, with King Numa sat writing down the laws on scrolls of paper using a reed pen. Egeria is quite different, though, and appears a simple and very naked nymph.

Inevitably, Numa grew old and then died. His wife Egeria was heartbroken: she left the city of Rome, and went deep into the forest, where her moaning disturbed those at the nearby shrine built by Orestes to Diana. Sister nymphs tried to comfort her, but couldn’t help. They told Egeria the tragic tale of Phaedra and Hippolytus, but that didn’t ease her grief either, and she dissolved into tears to be transformed by Diana into a spring.

The only accessible painting showing Egeria’s grief following the death of Numa is Claude Lorrain’s Landscape with the Nymph Egeria Weeping Over Numa from 1669.

Unfortunately, confusion has arisen over the true nature of this painting, as two images of details have been published on the internet purporting to be quite different and complete paintings. Claude’s painting itself is something of a puzzle too, and the result is that many of the images shown online of this work make no sense at all.

The full painting, above, shows a group of people and dogs in the left foreground, set in an idealised classical landscape on the coast.

The detail, shown below, reveals the five women in that group. Second from left is most probably the figure of Egeria, although there is nothing to show her profuse weeping or grief. One of the three women to the right of Egeria is Diana, with her spear, bow, arrows, and hunting dogs. It is unclear whether she is on bended knee, or stood behind holding the leash of one of the dogs.

More puzzling is the gesture of the woman (Diana or nymph) who is kneeling on one knee. Her left hand points towards Egeria, and her right is pointing away, towards the buildings down by the water. Her meaning is obscure in the context of the story of Egeria.

Whether this painting by Claude shows the story of Egeria and her grief over the death of Numa must surely be in doubt, and the evidence bears careful re-examination.

I hope that you enjoyed Saturday’s Mac Riddles, episode 308. Here are my solutions to them.

1: One of two of the three at the start, he left for 12 years with the successor before returning for one more thing.

Click for a solution

Steve Jobs (1955-2011)

One of two of the three at the start (co-founder of Apple with Steve Wozniak and Ronald Wayne), he left for 12 years with the successor (from 1985-1997 he ran NeXT) before returning (in 1997, when Apple bought NeXT) for one more thing (his catch-phrase used to introduce a new product at the end of a keynote). Wikipedia.

2: Writer for Bannister and Crun who originated and named it without a mouse.

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Jef Raskin (1943-2005)

Writer for Bannister and Crun (he first worked for Apple as a contract writer through his company Bannister and Crun) who originated and named it (he created and named the Macintosh project in 1979) without a mouse (he originally disliked the mouse). Wikipedia.

3: First to copy and paste, then changed Pascal and Newton, but was always modeless.

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Larry Tesler (1945-2020)

First to copy and paste (he devised these when working at Xerox PARC), then changed Pascal (he worked with Niklaus Wirth to develop Object Pascal for Lisa and Mac) and Newton (he led development of Apple’s Newton device), but was always modeless (throughout his career he eschewed modal interfaces). Wikipedia.

The common factor

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They’re three of the most influential people responsible for the development of the Mac.

I look forward to your putting alternative cases.

Macs keep time exceedingly precisely, although there are important differences here between Intel and Apple silicon models. Their most precise record of time is given in Mach Absolute Time (MAT), the number of ‘ticks’ since an arbitrary start. In Intel Macs, each tick occurs every nanosecond (10^-9 second), providing high resolution, but ticks are less frequent in Apple silicon chips, occurring once every 41.666… nanoseconds instead.

You can test this on an Apple silicon Mac using my free utility Mints, which has a convenient button to display Mach timebase information. Run Mints in native mode, the default as it’s a Universal App, and it reports the Arm values; force it to launch as an app translated by Rosetta, and it will give the same timebase as an Intel Mac.

Although entries in the log are recorded in MAT’s high resolution, most methods of accessing log entries lose much of that precision. The datestamps provided by the log show command, for example, round time to the nearest microsecond (10^-6 second), although it’s capable of delivering a field in MAT’s nanoseconds. The bundled Console app is similar, but lacks any option to display MAT. My Ulbow app can display both datestamps with microseconds and MAT, but until now LogUI has been limited to displaying only time in milliseconds (10^-3 second).

To put these into context, in each microsecond the P core in the CPU of an M4 chip can complete execution of over 1,000 instructions, and in a millisecond that becomes more than a million instructions.

LogUI has been constrained by the formatted output available using Date and DateFormatter in the macOS API, which appear to be incapable of generating time any more precisely than milliseconds. After several earlier unsuccessful attempts, I’m now able to obtain time in nanoseconds, using Calendar and DateComponents in the API. For example, to obtain a formatted string containing the nanosecond component of a Date variable named date:
let nanoSeconds = Calendar.current.component(.nanosecond, from: date)
let nsTime = String(format: "%09d", nanoSeconds)
The string nsTime can then be spliced into a formatted date string.

I have incorporated this into a new build of LogUI, which also has extended information about the log display in its Help book. LogUI 1.0 build 48 is now available from here: logui148
and from its Product Page.

Tomorrow I’ll consider whether these more precise times are of use, and what we can learn from them.