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While You Were Restarting

Of things that go bump on the boot.


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So the idea was to find out what's done on a cold boot.

Apple's main OS is a very busy critter of late. Flashbacks to the last WWDC and the presentation of 'ULAT' ('Unified Logging and Activity Tracing'). An unobtrusive logging system. That you probably never heard of, don't remember ever using, probably didn't ever use, you don't know of anyone else who uses it, there's no phoning home, what you know. And it's unobtrusive - it says so, right there on the label.

Yet if you look at the disk activity... It might not grab a lot of clocks, but you're talking serious megabytes. Constantly.

There's a lot more in other places too. There's all the 'container' areas, cache files... Half the system is files you once used, even if you didn't know it, all contributing to your user experience. But do they really need all those duplicates of duplicates of duplicates? It's time to find out.


All that sand... 9612 items in 'Containers' prior to clean-out. If you had one copper penny for every byte, you wouldn't need any more copper pennies. If you had one 'Benjamin' for every allocation block, or one pint of lager for every byte in extended attributes...

Prior to reboot, do a thorough clean. Shut down all but two user processes: Xfile and CLIX, CLIX to be used for its standard 'clean and reboot/shutdown' routine, and Xfile to be used, before that, to rid the system of other sundry cruft. Suffice it to say this particular machine, a cool MBP from the pre-Dongle Utopia™ era. is left with nary a stone, unturned or otherwise.

Then coming back up and straight into SUM (⌘S). Checking filesystem integrity, then mounting / for writing.

Time to look around again and get rid of more stuff.

/private/var/db: that's a good place to start. The three top ULAT directories are there: diagnostics, systemstats, uuidtext. Clean them all out. Every last item.

/private/var/folders. Clean out only your own. (Hands off 'zz'.)

So the system's looking good. Time for the boot.

36759. 36759 files created or modified on a hard boot. (64450 accessed, created, or modified). So says the filesystem. And the startup was not slow either. Went pretty well. 36759/64450 files.



That many files accessed, created, or modified? Yep, that's what it says. Perhaps some of that is unseen inode data? Aka 'disk optimisation'? Whatever.

/dev. Those files are always new. Note their creation date. Always created on boot. This boot had 316 of them.



Icon Services store. A monster. Was not cleaned out. Oops. (Make a note.) 273 files.



MobileAccessoryUpdater. 160 files appropriately located in a directory called 'fud'. 160. Are there mobile accessories on this box? No. Whatever.

Containers. 149 files made it back. And nothing had been run.

The user-specific /var/folders hive - which was cleaned out - was back with 371 files. And nothing had been run.

uuidtext. Part of ULAT. Generated 533 files on startup. Had been totally cleaned out to zero files in SUM.



systemstats. A meagre 63.

That's a lot of work for a cold boot, which still went admirably well, fast as ever.

Steve Jobs once harped on about startup times. Wanted things three seconds faster. Think of all the seconds being wasted, he was to have remarked.

How many seconds could be trimmed if all those files hadn't been created or modified?

About Rixstep

Stockholm/London-based Rixstep are a constellation of programmers and support staff from Radsoft Laboratories who tired of Windows vulnerabilities, Linux driver issues, and cursing x86 hardware all day long. Rixstep have many years of experience behind their efforts, with teaching and consulting credentials from the likes of British Aerospace, General Electric, Lockheed Martin, Lloyds TSB, SAAB Defence Systems, British Broadcasting Corporation, Barclays Bank, IBM, Microsoft, and Sony/Ericsson.

Rixstep and Radsoft products are or have been in use by Sweden's Royal Mail, Sony/Ericsson, the US Department of Defense, the offices of the US Supreme Court, the Government of Western Australia, the German Federal Police, Verizon Wireless, Los Alamos National Laboratory, Microsoft Corporation, the New York Times, Apple Inc, Oxford University, and hundreds of research institutes around the globe. See here.

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