My iMac - how alive is it when it's turned off?

[peterkienle]

I have a relatively recent iMac (Snow Leopard). I love it. No problems with it.

When I turn this computer off over night and then start back up in the morning it "forgets" which applications most documents are associated with. Meaning, where my documents normally show an icon resembling the application they belong to, after a cold start in the morning it's just a white rectangle and double-clicking it brings up "Application not found....". Obviously over the course of a few minutes things come back up.

So, I realize that MacOS does all this through the launch database which apparently gets rebuilt every time the machine starts up. On my machine I probably have more complications because my main drive is partitioned into several partitions and when applications allow themselves to be installed on another partition than the system disk I usually do that because I don't want my system disk too tight.

When I turn the machine off for a few hours during the day and then restart all these document/application links are still active.

Obviously I haven't done double-blind tests with various shut-off times but this has been the pattern on this machine since I remember.
But the pattern is repeatable: cold start after two hours or so no loss of links, cold start in the morning loss of links.

Is the launch database cached in RAM which sticks around for a few hours after shut down?

Just curious.

Thanks

Peter

[HenrikOlsen]

I suspect the information is cached with a time stamp of when it was last refreshed, so when you start during the day the information is recent enough that it'll be used from the cache, when you start in the morning it's too old and has to be rebuilt.

This is assuming your iMac isn't really turning itself off completely but is rather going to sleep while claiming to turn itself off, in accordance with the modern practice of lying to users "for their own good".

[Solfe]

You may want to reset the launching service if you are comfortable with the terminal.

This site has a good walk thru.

[ddubs]

Go into Applications / Utilities / Disk Utility and select your HD then there should be an option to repair permissions. Seems like it may be having issues updating wherever it stores file extension mappings, the information is probably cached in ram so when you warm boot - its still there. A cold boot will wipe out your vRAM.

[Cougar]

iMac manual says not to turn it off unless it's going to be for a few days. If it's only for a day or two, it says you should just put it to sleep.

[Trebuchet]

iMac manual says not to turn it off unless it's going to be for a few days. If it's only for a day or two, it says you should just put it to sleep.

I can't help reading "put it to sleep" in the veterinary sense. Does it involve a needle?

[Cougar]

I can't help reading "put it to sleep" in the veterinary sense. Does it involve a needle?

Heh. Well, you can't exactly put your computer to bed. I imagine it does dream, though... of what you were last doing with it. Just put the cursor in the corner - out like a light.

[cjl]

iMac manual says not to turn it off unless it's going to be for a few days. If it's only for a day or two, it says you should just put it to sleep.

That shouldn't affect the computer's behavior when shut down however. That recommendation is probably because sleep only uses a small amount more power than a full powerdown (a couple watts at most), and the computer can resume almost instantly from sleep (rather than the minute or so it takes from a cold boot). As far as the OS is concerned, there shouldn't really be any difference between being shut down for 5 minutes as compared to being shut down for a week.