Several of those who have already updated to macOS Tahoe 26.2 have remarked how much larger their download was than the 3.78 GB expected for Apple silicon Macs, with some reporting over 10 GB. Here I ponder how that could happen.
How is macOS now updated?
My understanding of the broad processes involved in current macOS updates is that the total downloaded for Macs of the same architecture starting from the same version should be identical.
Major components required for each update include:
contents of the System volume that have changed from the starting version for that update;
standard cryptexes containing Safari and its supporting components, and dyld caches. The latter differ between Intel Macs, which only receive Intel versions, and Apple silicon Macs, which receive Intel versions to support Rosetta 2 as well as their own Arm versions. Those probably account for much of the difference in size between Intel and Apple silicon updates. Note that Apple silicon Macs may also require updates to cryptexes used in AI, but those are most likely obtained outside the macOS update;
architecture-specific firmware;
new Recovery system;
the ‘update brain’ to run the update, including creation of the new SSV with its hash tree.
Those contrast with what’s required for a full installer upgrade (or reinstall), which consists of a single Universal app containing the whole contents of the SSV, cryptexes and firmware for both architectures, Recovery and the update brain.
Following decompression of the download, changed components are installed in the System volume, a snapshot made of that, and its hash tree is constructed. Updated cryptexes replace those from the previous version, the new Recovery system and firmware updates are installed.
For all Macs of both architectures being updated from the previous public release of macOS, creation of the new SSV should be identical, as their old SSVs are all signed with the same signature, as their contents are identical.
Combo updates
In any update, changed contents of the System volume depend greatly on the starting version of macOS installed. Updating from a previous beta can require different files to be replaced, compared with those from the last public release. In some cases, Apple may be able to provide a single updater that will convert both a Release Candidate and the last public release into the new version.
If that’s not feasible, Macs that are updating from a beta, or a public release before the last, will require what we used to call a Combo update, consisting of all changed contents since the last major version, in this case 26.0. Combo updates are inevitably significantly larger than single-step Delta updates from the last public release, but should remain smaller than a full installer.
Recent upgrades between major versions of macOS, such as 15.6 to 26.0, have tried to avoid full installers where possible, by adopting what’s effectively a Combo-style update, but slightly larger as a Combo+.
Thus, updates to 26.2 most probably consist of:
a Delta update from the last public release, 26.1, which might also be suitable for some beta releases;
a Combo update from 26.0, 26.0.1 or some beta releases.
a Combo+ update or full installer from earlier major versions of macOS.
As later minor versions are released, the size of the Combo update rises, as it’s required to incorporate more changes than for previous updates.
What would be surprising would be for two Macs of the same architecture updating from the same starting version of macOS to be provided with updates of significantly different size. I look forward to hearing from you if you consider that happened with the 26.2 update.
No BSI/RSR
What is puzzling about the 26.2 update is that it wasn’t preceded by a Background Security Improvement (BSI) or Rapid Security Response (RSR). Two of the top security vulnerabilities fixed in 26.2 (and in the Safari updates for 15.7.3 and 14.8.3) are both in WebKit, which is supplied in the Safari cryptex. These are for CVEs 2025-43529 and 2025-14174. Both were documented as already being exploited in older versions of macOS, in sophisticated attacks on targeted individuals. Both would appear to have been suitable for distribution prior to 26.2 in updated cryptexes, either by the existing RSR system or its replacement in Tahoe 26.1 of the BSI.
This appears to have been another missed opportunity for an RSR/BSI to have proved its value.
英國跨黨派任意拘留與人質事務國會小組（Parliamentary Group on Arbitrary Detention and Hostage Affairs）發表聲明批評，這項定罪顯示英國政府的失職，因「政府先前未能更強硬要求立即釋放黎智英」。聲明指出，美國、加拿大與澳洲等國，已成功促成其公民從中國與香港的任意拘留中獲釋，「儘管英國與香港之間有《香港基本法》所保障的特殊國際義務關係，英國卻未能做到」。
A bombed-out building in Marawi in 2022, five years after Islamic State-affiliated militants and government forces waged a devastating battle for control of the city.
US President Donald Trump has filed a defamation lawsuit against the BBC over an edit of his 6 January 2021 speech in a Panorama documentary.
Trump has requested billions of dollars in damages, according to court documents filed in Florida.
The BBC apologised to Trump in November, but rejected his demands for compensation and disagreed there was any "basis for a defamation claim".
Trump's legal team accused the BBC of defaming him by "intentionally, maliciously, and deceptively doctoring his speech". The BBC has not yet responded to the lawsuit being filed.
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Thousands of drivers could have speeding fines cancelled after a fault saw some cameras falsely triggered on English A roads and motorways.
National Highways said it had found 2,650 wrongful speed camera activations since 2021 due to a delay between cameras and variable speed signs.
Affected drivers will be contacted by police and be reimbursed for any fines while points will be removed from their licences where needed.
Not all camera activations are enforced, so not all of the wrongful activations will have resulted in fines.
National Highways apologised for the error and chief executive Nick Harris said a fix for the issue has been identified.
"Safety is our number one priority… All drivers should continue observing the posted speed limits as normal. Anyone who has been impacted will be contacted by the relevant police force," he said.
National Highways, which runs England's motorways, blamed an "anomaly" in how variable speed cameras were interacting with signs on some A roads and motorways.
It meant a delay of around 10 seconds between cameras and relevant variable speed signs, meaning some drivers were incorrectly identified as speeding after the limit had changed.
The body said the 2,650 incidents since 2021 represent fewer than two each day, compared with more than 6 million activations of speed cameras on the affected roads over the same period.
It said the anomaly has impacted 10% of England's motorways and major A roads.
It is working with police to check activations and promised nobody will now be wrongly prosecuted.
Meanwhile, police forces have stopped issuing fines from variable cameras until they have confidence in their accuracy.
A Department for Transport spokesperson said: "We apologise to anyone who has been affected. Safety was never compromised, and we are working with policing to ensure nobody is incorrectly prosecuted in future.
"Enforcement is still in place, and the public can remain confident that only motorists who break the rules will be penalised."
Trade minister Chris Bryant and his Korean counterpart Yeo Han-koo announced the deal in London
The UK and South Korea have finalised a trade deal which the government says will create thousands of jobs and bring billions into the British economy.
British industries including pharmaceuticals, car manufacturing, alcohol and financial services are expected to benefit from an extension to the current tariff-free trade on most goods and services.
The deal is the fourth such agreement struck by the Labour government, following deals with the EU, US and India — none of which have had a material impact on the UK's economy so far.
South Korean culture, including music, cosmetics and food, has become much more popular in the UK in recent years.
Trade minister Chris Bryant announced the deal in Samsung's flagship store in London on Monday night, accompanied by his Korean counterpart Yeo Han-koo.
Under the deal, 98% of trade will continue to be tariff free, the same terms that the EU has with South Korea, and which the UK maintained temporarily after Brexit.
The UK's agreement with South Korea was set to expire in January 2026, but the new agreement will protect £2bn of UK exports from an increase in tariffs.
Prime Minister Keir Starmer said the deal was "a huge win for British business".
"This deal making trade even easier between us will help boost the economy - supporting jobs and growth which will be felt all over the country," he said.
Bryant said the deal would give "cast-iron protections to our key industries to speed up economic growth as part of our Plan for Change".
South Korea is the UK's 25th largest trading partner, according to the Department for Business and Trade. In the 12 months to the end of June this year, it accounted for 0.8% of the UK's total trade.
Over that same 12-month period, official figures show UK exports to South Korea fell 16.4% and South Korean exports to the UK fell 10.8%.
South Korea's trade minister told the BBC that South Korea and Britain's economies "are complimentary", and denied that the fall in trade between the nations suggested the relationship wasn't as important as it used to be.
Han-koo said the new agreement was more about reducing non-tariff barriers, such as making rules around product origin more business friendly, and creating new digital and investment protections.
"So these two economies can win by cooperating closer through this kind of framework," he added.
Han-koo also said Britain can serve as a gateway for South Korea in its trade with Europe, while South Korea can serve as a gateway to Asia for British companies.
The South Korean deal is the latest in a series of post-Brexit trade agreements, but the independent budget forecaster, the OBR, has so far deemed deals done with those larger partners as unlikely to make a measurable impact on the UK economy by 2030.
The government has said that its various trade agreements struck this year will grow the British economy by creating jobs and cutting red tape for small businesses.
But its own assessment showed that the deal with India will only increase GDP by between 0.11% and 0.14%.
That deal in particular was criticised for potentially undercutting British workers.
India is the UK's 10th-largest trading partner, accounting for 2.5% of British trade.
'Great news'
UK companies including Bentley Motors, Jaguar Land Rover (JLR) and Guinness owner Diageo welcomed the news of the South Korean deal.
Frank-Steffen Walliser, chairman and chief executive of Bentley Motors, said that South Korea is a key market for the company and the wider luxury vehicle market.
"To secure immediate ongoing access to South Korea and a positive long term trade deal, is great news. Smooth international trade is vital to UK automotive business growth."
Diageo's interim chief executive Nik Jhangiani said it would "help satisfy the growing demand from South Korean consumers" for Guinness, which is canned in Runcorn, Cheshire.
Emily Weaver Roads, interim international director at the Scotch Whisky Association, said the Asia-Pacific region was the largest regional market by value for whisky.
"The reduction of trade barriers in the Republic of Korea will further enhance Scotch Whisky's access to an important market, especially for single malts."
Trump and Xi last met face-to-face in October, when both of them visited South Korea
US President Donald Trump says he has asked Chinese leader Xi Jinping to "consider" releasing Jimmy Lai, the Hong Kong pro-democracy tycoon who was earlier this week found guilty under the city's controversial national security law.
"I feel so badly," Trump told reporters. "I spoke to President Xi about it and I asked to consider his release."
The UK similarly called for the 78-year-old to be "immediately released", with UK Foreign Secretary Yvette Cooper condemning the ruling, calling it a "politically motivated persecution".
Lai, who is a British citizen, has been in jail since December 2020 and is due to be sentenced early next year. He faces a maximum term of life in prison.
Trump made the brief comment to reporters at the White House on Monday - but did not specify when he had brought Lai's case up to Xi.
"He's an older man and he's not well. So I did put that request out. We'll see what happens, okay?," he said.
His comments come after a Hong Kong court on Monday found Lai guilty of colluding with foreign forces.
The verdict was welcomed by Hong Kong's chief executive John Lee, who said that Lai's actions had "damaged the country's interests and the welfare of Hong Kongers", but rights groups called it "a cruel judicial farce".
"He has been targeted by the Chinese and Hong Kong governments for peacefully exercising his right to freedom of expression," UK Foreign Secretary Yvette Cooper had told Parliament on Monday, calling for Lai's "immediate release".
She added that the Foreign Office has summoned the Chinese Ambassador to "underline our position in the strongest terms", adding that it was "heartbreaking that such a violation of a British man's rights could occur in Hong Kong".
China's foreign ministry had earlier on Monday dismissed criticisms of Lai's trial, describing them as "brazen defamation and smearing of the judicial system in Hong Kong".
Lai was on Monday convicted under the city's controversial national security law - which rights groups say is used to crush dissent, but which Beijing defends as essential for the city's stability.
He was also convicted of publishing seditious material on Apple Daily under a separate colonial-era law.
His detention and conviction have drawn concern from rights groups and foreign leaders, who have long called for his release.
His children have voiced serious concerns about Lai's deteriorating health in prison, with Sebastien telling the BBC earlier this year that given his father's age and health, he could "die in prison".
It was a night at the museum like no other. As the staccato sound of firecrackers and explosions rang out across Martyr’s Square in the heart of Tripoli, for once it was not Libya’s militias battling it out for a larger stake in the country’s oil economy, but a huge firework display celebrating the reopening of one of the finest museums in the Mediterranean.
The National Museum of Libya – housing Africa’s greatest collection of classical antiquities in Tripoli’s historic Red Castle complex – had been closed for nearly 14 years due to the civil war that followed the former dictator Muammar Gaddafi’s downfall. Its ceremonial reopening came at the climax of a lavish show compressing Libya’s rich history and attended by diplomats and Arab celebrities, with a full-size Italian orchestra, acrobats, dancers, arches of fire and lights projected on to the fort. It did not lack for circus drama or cost, peaking with a billowing Ottoman sailing ship arriving high above the port on wires to be greeted by an angelic-appearing Libyan woman.
Abdul Hamid Dbeibah, the prime minister of Libya’s UN-recognised government of national unity – Libya has two rival governments, one in the east and one in the west – was then taken to the doors of the museum, where he wielded a big stick, as if at the opening of the British parliament, to hammer on them and demand entry. The giant wooden doors drew open slowly and crowds poured in.
Inside, Libya’s history revealed itself – a record of a vast country shaped by successive occupations from Greek to Roman, Ottoman and Italian. On its four floors could be found cave paintings worthy of Lascaux; 5,000-year-old mummies from the ancient settlements of Uan Muhuggiag in Libya’s deep south; tablets in the Punic alphabet; and countless treasures from the still largely unvisited Roman coastal cities of Leptis Magna and Sabratha, including spell-binding mosaics, friezes and statues of great public figures and gods. Gone, however, was Gaddafi’s turquoise VW beetle, once given pride of place in the collection and one of the museum’s few losses to the uprising.
Speaking the next day in offices once occupied by Italian archeologists on the top floor of the Red Castle, Dr Mustafa Turjman, the former head of the department of antiquities, recalled evacuating all the museum’s works to secret hideaways to keep them from robbers and smugglers. He admitted there was hesitation about the reopening, after artefacts from the tiniest coin to giant statues were brought back from hiding.
Turjman said the museum showed people what Libya had once been – a region of great cultural and economic self-confidence, well connected to the world beyond the sea. “We are part of the Mediterranean,” he said.
This was not just a moment for classicists, or lovers of Libya’s rich history, Turjman said, but a moment for a country riven between its eastern and western regions to come together. “This is a museum about the whole of Libya … the archaeological masterpieces of the whole country. It is a force for unification,” he said. “So when people from Tripoli [in the west] come here they see statues from [the eastern region of] Cyrenaica, and when Cyrenaicans come they see their heritage, so it helps reunify the two regions … We are relatives. Their cousins are here and out cousins are here.”
Turjman hopes the museum will help educate Libyans after the distorted teaching of the Gaddafi era, and the first few weeks of the museum’s opening is dedicated to bringing in schoolchildren. “The most important thing is teaching the mind. Teaching how to respect time and history, and how to respect others, and to be involved in the world,” he said. “We have to build the minds. My generation studied the philosophy of the Greeks as part of our heritage, but this stopped. Libya is often an arid remote region, but we kept this heritage: it shows our willpower.”
Persuading the world to see Libya “through optimist’s eyes”, as the government slogan puts it, could be a tough ask. True, embassies are reopening, as are long-closed luxury hotels. The British oil multinational BP has reopened its office and new oil investments are planned. Luxury waterfront marinas have been built. A drive-in food complex has sprung up. But there is much to overcome.
A Libyan passport provides free passage to virtually nowhere and the country remains close to the bottom of world league tables for press freedom and corruption. On the museum’s opening night a notorious people smuggler, Ahmed al-Dabbashi, was reported shot dead in a gunfight with Libyan security forces in Sabratha. Australia only last week advised its citizens to stay away; in Tripoli’s al-Madina souq some of the shops say they are open only two hours a day due to the lack of visitors.
Dbeibah is disarmingly frank in interview about his country’s failings, including the arrest of three of his ministers in a corruption investigation, even if he insisted spending was transparent down to the last dinar. He admitted the country’s inability to shake off its dependency on the oil economy meant that 2.5 millions Libyans were on the government payroll – roughly a third of the population. Distorting but popular subsidies also mean petrol is cheaper than water, costing less than £1 to fill a tank. The price makes it a target for smuggling that the various auditing agencies seem incapable of preventing.
Pressed on why the east and west of the country had set up conflicting parallel institutions since the 2014 uprising, he blamed politicians and not the people.
Dbeibah has not been elected to office. Becoming prime minister in 2021 as part of a UN-supervised process, he was due to stay in power only until elections across the country could be held. But a parliament or president with a meaningful mandate remains a distant prospect so long as the political elite in east and west prefer the personal riches disunity brings.
The UN Libya mission is organising “a structured dialogue” in an effort to reconcile the country ahead of elections possibly next year, but Dbeibah says he opposes holding a vote until there has been a referendum on a new constitution. The merry-go-round of west and east setting preconditions for elections never stops. One Libyan official said: “Libyans have no clue about politics. Gaddafi prevented that.”
One of the very first visitors to the museum was the Egyptian comedian and TV host Bassem Youssef, who has millions of social media followers and has appeared on Piers Morgan’s TV show to speak about the Gaza war.
He said it had taken time to convince his wife it would be safe to visit Libya, and reflected on “the rectangular screen in our pockets that shapes our consciousness and minds”. He said Libya was in the news only when it was embroiled in conflict or other problems, and when things calmed down the media were no longer interested. It was as if for an Arab country to be in the news, something had to be wrong, he said.
“The image of any country or society has nothing to do with the reality on the ground, but rather with the lens through which one sees reality,” he said. “Unfortunately, we must admit that this lens, which transmits the image of most of our Arab countries, is broken, cracked and distorted.”
各位好，在得克萨斯西部转了两周，昨天回到生活世界的日常，继续读书读报，知己、知彼、知天下。在西部旷野中，一周不读报，心情会好很多。得州本地人很多是straight talker，说话直来直去。回家路上，在90号公路边的餐馆，一位服务员大妈，满头白发，身材纤细，声音悦耳。她名叫Betsy。吃饭的时候，电视正在放白宫新闻，她随口说了一句“that bonehead in high court”。这是得克萨斯老乡的土话，土得掉渣，同时又温文尔雅。
回到家，社区已经是家家户户，张灯结彩。圣诞节快到了，街上一片喜庆色彩。看看新闻，美国这边，that bonehead in high court继续制造头条，很多新闻已经成了无意义的噪音。中国那边，红色基因土皇帝在宣布胜利，而中国政府发布的最新经济指标，却是寒风刺骨。
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