Tech – www.chrisrcook.com

Retrieving the Time Machine Estimated Full Backup Size for MacOS Tahoe

Well, it’s been a little while since I last looked at sizing Time Machine backups on MacOS and, with MacOS 26 (‘Tahoe’), the magic incantation needed to pull that information out has changed.

Open up a terminal and enter the following…

log show --predicate 'subsystem == "com.apple.TimeMachine"' --info | grep "will be in backup of all sources"

…and this will print out a number of records from previous Time Machine sessions thus…

2025-11-17 08:59:01.989807+0000 0xdd79ec   Info        0x0                  27411  0    backupd: (TimeMachine) [com.apple.TimeMachine:SizingProgress] Estimated a total of 3112764 files (13.52 TB) will be in backup of all sources
2025-11-17 09:54:37.554473+0000 0xde7d23   Info        0x0                  27411  0    backupd: (TimeMachine) [com.apple.TimeMachine:SizingProgress] Estimated a total of 3113582 files (13.51 TB) will be in backup of all sources
2025-11-17 10:54:38.754477+0000 0xdfb366   Info        0x0                  27411  0    backupd: (TimeMachine) [com.apple.TimeMachine:SizingProgress] Estimated a total of 3119251 files (13.51 TB) will be in backup of all sources
2025-11-17 11:54:25.417194+0000 0xe0dd3f   Info        0x0                  27411  0    backupd: (TimeMachine) [com.apple.TimeMachine:SizingProgress] Estimated a total of 3123208 files (13.51 TB) will be in backup of all sources

Film Formats, Film Archives

Adam Savage has a couple of nice videos from the Paramount Film Archives. I especially enjoyed the second of these on the various media formats used over the years.

New Old Stock IBM OS/2 Warp 3.0

Abort Retry Fail has a really nice post on opening and installing a new old stock Red Spine release of OS/2 Warp 3.0.

Now, while I’ve played around with OS/2 Warp 4.0 and 4.52 as part of Period Sites in Period Browsers, Warp 3.0 is not one I’ve yet reached.

And how uncanny it looks! Familiar but alien. Windows 3.1 but not. I should really get an instance of this up and running just so I can really feel – rather than just see – the differences between how I expect it to work and how it does work…

Anyway, I strongly suggest going and having a read of the article and a look at the pretty pictures.

Language Models are Injective and Hence Invertible

Arxiv has an interesting paper on LLM reversibility and, while the maths is way over my head, the implications of it are definitely interesting.

The Cray Y-MP C90

It’s the start of the month and over at Retro Computer Adverts there’s a rather lovely brochure for the Cray Y-MP C90 in all of it’s early 1990s glory.

ISS in Real Time

The ISS in Real Time is a fully interactive timeline of the ISS’s operation and is more than a little cool. They’ve managed to dig out all sorts of old footage and photos, crew manifests and daily schedules, and have put it all together in a pretty but usable interface. The flightpath widget is also a nice way of showing where the station was at any particular time.

First Shape Found That Can’t Pass Through Itself

Quanta Magazine has a nice article on a question I’d not even thought about – can all shapes pass through themselves? And, apparently, the answer is ‘no’, but only for a very limited number of shapes.

The article is pretty good and breaks down the problem and its history quite nicely. Go read!

ChatGPT Atlas User Agent.

It looks like ChatGPT’s new browser is identifying itself as a bog standard Chrome instance. That should make it both hard to block and hard to track.

"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36"

The ICT 1301 Resurrection Project

And now for something really rather fab to start your day off with – ICT 1301 resurrection project! Their goal is to restore the UK’s oldest 2nd Generation Electronic Stored Program Computer to functioning order.

They also have a lovely set of digitised technical manuals up to view!

Fab!

The Worst-selling Microsoft Software Product of All Time: OS/2 for the Mach 20

Raymond Chen at ‘The Old New Thing’ has a lovely tale about what could be Microsoft’s worst selling product ever – OS/2 for the Mach 20.

According to that person’s memory (which given the amount time that has elapsed, means that we should basically be saying “according to legend” at this point), a total of eleven copies of “OS/2 for Mach 20” were ever sold, and eight of them were returned.
Raymond Chen, The Old New Thing.

I’ve seen a few expansion cards as part of choosing images for ‘Retro Computer Adverts‘, but the Mach 10| 20 is not one I’ve yet stumbled across. And as for ads for ‘OS/2 for Mach 20’? Not a sausage!

Tag: Tech