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Last Week on My Mac: Seconds out

By: hoakley
1 February 2026 at 16:00

In 1657, one of the great scientists of the Dutch Golden Age, Christian Huygens, invented the pendulum clock, the first timekeeping device accurate enough to make a second hand worthwhile, as it typically only lost about 15 seconds per day. It was another century before John Harrison developed his marine chronometer, a clock sufficiently accurate to enable precise determinations of longitude. Another hundred years later, with the coming of railways across Europe, ordinary people started synchronising clocks so they caught their train, and our ancestors soon became the first slaves to time.

I’m beginning to wonder whether Apple intends reversing that history. Have you not noticed something odd about setting times in more recent Mac apps, how few allow you to set the seconds? You can see what has happened over the last few years in my log browsers, Ulbow and LogUI.

Most of Ulbow’s interface was written using AppKit seven years ago, and it uses a standard Date Picker with elements containing the year, month, day, hour, minute and second. Given that you can get more than 10,000 log entries in a second, I would have preferred to offer decimal seconds, but that isn’t possible within the standard AppKit picker.

LogUI was written from the start using Apple’s more recent substitute for AppKit, SwiftUI, eighteen months ago. That doesn’t use the AppKit Date Picker, but has its shiny new DatePicker instead. Components available in macOS are there limited to year, month, day, hour and minute. To be able to include seconds your code must be written for an Apple Watch, as macOS, iOS and iPadOS don’t allow seconds at all. That’s why you have to enter them in a separate TextField, although that could perhaps allow the use of decimal seconds.

When I wanted to obtain higher resolution timestamps for log entries in LogUI, I discovered that standard date formatting in macOS only resolves to milliseconds (10^-3 second), and couldn’t stretch to microseconds (10^-6 second), let alone the nanoseconds (10^-9 second) that can be obtained from Mach absolute time, as used internally in parts of macOS. Even that reference has recently become lower resolution, as each ‘tick’ in Apple silicon Macs occurs every 41.67 nanoseconds, rather than once every nanosecond as in Intel Macs.

There’s another difference between Ulbow and LogUI with regard to timestamps that you’re less likely to be aware of: Ulbow obtains its log records indirectly using the log show command, which can include the Mach absolute time of each entry. Instead, LogUI accesses those entries direct through the more recent OSLog API, which doesn’t currently expose such precise times.

Lest this appear too far removed from the world of the user, look in the menu bar clock’s settings, and you’ll see Display the time with seconds is an option, but not the default. When the clock is shown on the Lock Screen or screensaver, it only displays hours and minutes, never seconds, neither can any of the digital clock widgets supplied with macOS. While the Clock app does support decimal seconds, that’s only permitted in its Stopwatch where hundredths are displayed, as they are on an Apple Watch and other devices.

This becomes stranger still when you consider the methods used to synchronise internal clocks. Since High Sierra, macOS has used its own timed service, which Apple describes as “synchronizing the clock with reference clocks via technologies like NTP”, that’s the Internet service provided by time.apple.com as in Date & Time settings. When accessed over the Internet, it’s generally accepted that NTP should be accurate to within tens of milliseconds, although that can at times worsen to 100 milliseconds or more.

As far as I’m aware, no Mac has ever had a GPS receiver built into it, but every iPhone apart from the earliest, and those iPads with cellular support, include assisted GPS and GLONASS. Those are capable of providing time accurate to about 100 and 200 nanoseconds respectively. Even my 11-year-old car corrects its clock using GPS.

Although our Macs and devices can share almost everything else now, my Macs appear unable to adjust their clocks to the more accurate time that should be available to my iPhone. But as iOS is so shy about displaying seconds anywhere, it makes me wonder whether iPhones make full use of GPS time, or mostly rely on that obtained from the nearest cellular mast.

I’m curious whether this is a deliberate campaign to abolish seconds wherever possible, or just the result of doing what looks sufficient. Maybe I’m a mere slave to time, and the Time Lords in Apple Park are on a mission to cure me by travelling back four centuries.

湄洲天后宫

By: fivestone
13 July 2024 at 16:39

湄洲岛,传说是妈祖林默的故乡。北宋年间,岛上出现了最早的妈祖庙(灵女祠),经历朝扩建为大片宫殿,文革期间全毁,1980 年代后,由散落到各地的香火信徒集资重建的仿宋建筑群。被妈祖信徒们戏称为「东方麦加」……

除了在码头附近的大型祖庙外,湄洲岛上的几乎每个村落,都有各自的妈祖庙,盖的都不小。去不同的堂口进香,也是信仰和交流体系的一部分;尤其是在一些祭日,人们会扛着妈祖像,把所有的庙都逛一遍。

但其中一些庙,路不熟的话,并不好找。于是我上岛时,被唤醒了踩地图之魂,骑着电动车,把所有妈祖庙都找了一遍,标上准确的 GPS 位置。

每座庙的 GPS 位置(WGS 84),由北向南:

地点纬度 °N经度 °E
湄洲祖庙25.09379119.14317
上英宫25.09035119.12628
上林宫25.09007119.12889
上兴宫25.08973119.13972
寨山宫25.08211119.12082
莲池宫25.08169119.12598
回龙宫25.08014119.11606
龙兴宫25.08008119.12268
进福宫25.07523119.11157
湖石宫25.07453119.12075
天后行宫25.07068119.11253
文兴宫25.06453119.12972
白石宫25.06218119.12382
天利宫25.04815119.11863
麟开宫25.04398119.11643
麟山宫25.04026119.11625

大约有一半的妈祖庙,是比较好找的,就在主路的边上,甚至在高德地图就能搜到。但其中也有坑,譬如,我第一个去的是「莲池宫」,按地图上搜到的位置,找过去,却关了门。因为是第一家,我并不知道岛上的庙,是什么样子的,于是以为自己不走运,很多庙不在祭日都会关门;正在遗憾,看到里面仿佛有人,敲门问了问,才发现,这家莲池堂,其实是个耶稣教会………

真正的莲池宫,藏在另一个方向的村子里,穿过几条土路才会看到。所有的妈祖庙,其实都是这种金碧堂皇的样子,平日一直开着门。

岛上还有很多其它的庙:有耶稣教会、有完全不供奉妈祖的佛寺、有很小只的土地庙、关帝庙、海神庙、有家族私姓的祠堂、有看着很像妈祖庙,但不知是做什么的「三一教」……海边的「天后行宫」,在妈祖庙背后,修了个更大一号的如来大雄宝殿,于是感觉并不是很靠谱,有人介绍岛上除了祖庙,有 15 家妈祖庙,就没有把天后行宫算在里面。

但有些神灵,是可以放在妈祖庙的侧位一起供的,譬如,齐天大圣……

有的庙正在修葺,就让妈祖像暂居到村子的土地庙/城隍庙里,因为妈祖更大牌,所以城隍要把中间的位子让出来~

有的已经建好了新庙,于是旧庙广场上,用来晒鱼干。

所有的庙旁边都有戏台,还有很多社区的老年中心,也挂牌建在庙场旁边。但大家也经常直接在庙里活动:织网、打牌……赌金还不小。

庙修的都很精美,但赞助者的签名,就磕碜了点儿。

希望小朋友考出好成绩。

路过其它小庙在举行仪式,搭台唱戏。但感觉不同信徒之间,是有些隔绝的。很多时候问路,几百米外的妈祖庙,对方并不知道在哪里,甚至没听说过。

岛上有很多游客、有夜市、很漂亮的画了彩虹线的海边公路。游客们穿着小清新的样子,打卡拍照。但似乎很少有人会去这些庙里逛逛。似乎是两个世界。

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