Idle Memory Question? What is it?

[iriejedi]

I have 1.5 gigs of memory on my G5 2.5dp and started seeing some odd program crashs, iPhoto, Photoshop CS and iMovie, all memory hog programs.... so I thought how odd....OS X is supposed to be fairly stable.

So I ran my profile and 1 gig of the memory was "Reserved" or 'blue color' (bottom term of left column of memory descriptions) leaving less then 50 megs as "FREE" or Green Memory... I quit EVERYTHING and then still 1 gig was (blue) and around 130megs green.

After a restart all seemed normal... 1.2gigs as 'free' or green color coded space but this reluctance to free memory was kinda odd I thought to myself.... So my question is does anyone know what this means and if that could have caused my problems? What about a way to reset memory without restarting?

Thanks

On OS X Newbie
Iriejedi

 

[varmit]

I have 1.5 gigs of memory on my G5 2.5dp and started seeing some odd program crashs, iPhoto, Photoshop CS and iMovie, all memory hog programs.... so I thought how odd....OS X is supposed to be fairly stable.

So I ran my profile and 1 gig of the memory was "Reserved" or 'blue color' (bottom term of left column of memory descriptions) leaving less then 50 megs as "FREE" or Green Memory... I quit EVERYTHING and then still 1 gig was (blue) and around 130megs green.

After a restart all seemed normal... 1.2gigs as 'free' or green color coded space but this reluctance to free memory was kinda odd I thought to myself.... So my question is does anyone know what this means and if that could have caused my problems? What about a way to reset memory without restarting?

Thanks

On OS X Newbie
Iriejedi

Idle memory I believe is memory at was used by a program but not anymore. But it still has all the information still in it from when the program was running. So if you started it up the program again, it would open quicker because its still in RAM. But if you ran a different program, it would take some of that Idle RAM back for use with the new open program. Thats why on restart its all free, because no programs have been run yet to take up the RAM.

Sounds like you have a bad stick of RAM since it happens on big programs that take up memory. One bad stick causes the whole thing to go down. Did you add some third party RAM? Might want to do the hardware test, or take it out and see if it still crashes.

 

[zimv20]

sorry, varmit, but i don't think that's right.

iriejedi -- i'm not sure from where you're getting the term 'idle'. what do you mean you ran your profile?

if 'idle' refers to 'inactive' memory, such as is shown in the command line top command, i believe that refers to memory that's either been paged or swapped out to the hard drive. the program it's assigned to is still running, but that chunk of memory hasn't been accessed in a while, so the OS opted to store it and free up memory for more active processes.

in unix, when a process goes away, its memory is returned to the heap for use by other processes. there's no method by which it is can be assigned, intact, back to the same "application." unix is unaware of applications, it knows processes. and as far as the OS is concerned, processes and their id's are unique and cannot be associated w/ each other by way of relaunching an app.

also, bad memory usually results in a machine not booting at all.

sounds like the problem may be a memory leak in some process. i.e. the process keeps requesting memory from the heap, but never returns it when its done. eventually, it'll eat up all the available memory. use Applications/Utilities/Activity Monitor to see which app is eating up more memory than it should.

 

[zimv20]

I quit EVERYTHING and then still 1 gig was (blue) and around 130megs green.

btw, just because there's no apps running doesn't mean there are no processes running. in fact, there are a lot. if Activity Viewer doesn't reveal the culprit, make sure you're looking at All Processes (from the dropdown) and sort by Virtual Memory.

keep an eye on both memory columns and see if it ever decreases. if it only goes up, it's likely a leak. report back on the process name and memory behavior.

do you have Office installed?

 

[crazzyeddie]

i believe that refers to memory that's been swapped out to the hard drive. the program it's assigned to is still running, but that chunk of memory hasn't been accessed in a while, so the OS opted to store it and free up memory for more active processes.

Thats not correct. Page ins and page outs refer to memory files that are written and read from the hard disk. I believe that varmit was correct.

 

[zimv20]

Thats not correct. Page ins and page outs refer to memory files that are written and read from the hard disk.

wow, i had JUST edited my text above to add paging.

paging: the OS writes a chunk of memory to the drive
swapping: the OS writes a process, including its memory, to the drive

either way, it involves writing memory to disk, and i believe that's the 'inactive' memory to which i referred.

I believe that varmit was correct.

in that memory contents from dead processes can magically be assigned to new processes? i don't think so.

 

[zimv20]

jedi - run the following commands in Terminal and report back the results. dunno if you're familiar w/ command line, but don't include the percent sign.

% ls -ls /var/vm
% vm_stat