Memory question (wired, free, etc)

[michaelsanford]

I've been using MaxMenus previously on my iMac TFT for information, but given that I have 786 RAM the ram meter was rarely important since I couldn't really run out with my usage.

Now my iBook is another story. I see options for Active, Wired, Inactive. Inactive is an amount which is less than the total free space of the graph (there's extra space in white (or transparent, don't know, not user selectable)).

Basically: does Inactive mean RAM which has been requested and reserved by an application and then released and is waiting for another app to use, and the white part is RAM which has never been addressed since boot?

[Arden]

As always, a screenshot would be helpful, but I think inactive memory is that which has no purpose at the moment... unless there's a space that says free memory.

[michaelsanford]

Blue is wired
Red is active
Grey is inavtive
The white (shown blue because it's clicked) at the top is not assigned any colour, and there is no place to assign it a colour in the preference pane.

Basically I'm asking, what's the different between wired and active, and the difference between inactive and the rest of the ram that is not assigned a colour.

[Darkshadow]

The active ram is memory actively being used by applications. I'm not sure what the wired memory is.

The inactive ram is memory that has been used by an application and then discarded. The memory manager will use that ram if it is needed, though, so you could consider it free ram. In fact, if you look at that picture, you'll see that it says 62.9 is inactive and 154.9 is free, but above that it says 217.8 is free - that's just the previous two added together.

I'm going to guess that the white part is the free ram. I haven't ever used that application before, but that's what it looks like to me.

[michaelsanford]

Cool that's what I guessed. I'm still wondering what the Wired/Active difference is; could it be wired = physical and active = physical + swap?

Hmm this is curious, simultaneously:
top PhysMem:
38.3M wired, 140M active, 123M inactive, 302M used, 17.9M free

menumeters:
178,3 used; 141,7 free; 320,0 total

uuh...

[bogomips]

Originally Posted by michaelsanford

Cool that's what I guessed. I'm still wondering what the Wired/Active difference is; could it be wired = physical and active = physical + swap?

Hmm this is curious, simultaneously:
top PhysMem:
38.3M wired, 140M active, 123M inactive, 302M used, 17.9M free

menumeters:
178,3 used; 141,7 free; 320,0 total

uuh...

check the following link: http://developer.apple.com/documenta..._Mac_OS_X.html

At least it sets the record straight regarding wired memory.

kind regards
bogomips

[michaelsanford]

Cool, this answers many other unasked questions about VM on OSX thanks!