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#39 Periodic and Prebinding

Some_future_release
open
5
2012-10-09
2005-09-27
David
No

How about if there was a feature to have AppleJack run periodic
tasks (see "man periodic" for information) on a system? These
tasks are by default scheduled to run at rather inconvenient times,
so not all users will have them done regularly. Does this apply to
Tiger? I am not sure if launchd improves things, as I am running
10.3.9....

A second, probably slightly more useful, neat feature would be if
AppleJack could update a system's prebinding (see http://
www.kernelthread.com/mac/apme/optimizations/#SIX for more
information).

Both of these ideas might not be all that great of additions, but are
part of my list of generic-things-to-do-which-seem-to-help. Thanks
for making a great utility with AppleJack.

Discussion

  • Logged In: YES
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    An update pre-binding function might come in handy, but I
    have yet to see a scenario where bad pre-binding is getting
    in the way of being able to start up your Mac. If you have
    any case studies, or reports of people being unable to start
    up until they fixed their prebinding, I would be glad to
    look into this and add it to AppleJack.

     
  • Ilgaz
    Ilgaz
    2007-07-12

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    http://www.unsanity.org/archives/mac_os_x/shock_and_awe.php

    as prebinding is "optimisation" process, it is something like "added performance", not something needed to have system booted.

    What if the issue outlined above happens? Applejack would be responsible for system component missing. :)

    Pasting the scenario below and I believe it could be root of "OS X update killed my mac" reports.

    "When you see the "Optimizing System Performance" phase of a software update, Mac OS X is really updating prebinding. Updating prebinding has a very, very nasty bug in it (look at _dyld_update_prebinding). If multiple processes are updating prebinding at the same time, then it is possible for a system file to be completely zero'd out. Basically, all data in the file is deleted and it is replaced with nothing."

     
  • Ilgaz
    Ilgaz
    2007-07-12

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    sorry for double comment. Running the script "daily" has a potential issue too. Daily script does do something very very important: It backs up the Netinfo database to disk replacing old backup. So, lets say if user can't boot into OS X because of netinfo database corruption and he/she runs "daily" inside Applejack. It means the working backup will be replaced by non working one and he/she will get completely stuck without users (of course, files stay).

    It happened to me once and I had to carry steps mentioned in
    http://docs.info.apple.com/article.html?artnum=107210

    That time, I wasn't aware of excellent utilities like "anacron" (freeware) or "macaroni" so the scripts didn't run at all. If I had the backups created by daily script, I would recover. If I had actual working backups and some utility replaced them with non working current ones, it would be bad :)