Question on "iStat Pro" Widget

[lugesm]

A very neat widget !

This little utility lists under "Memory"
Wired
Active
Inactive
Free

The last two categories are self-explanatory; but I don't understand the "Wired" category. Also, why is "Inactive" not part of "Free"? Is "Inactive" reserved for some application?

Appreciate your comments.

 

[mkrishnan]

http://docs.info.apple.com/article.html?artnum=107918

Wired memory
This information can't be cached to disk, so it must stay in RAM. The amount depends on what applications you are using.

Active memory
This information is currently in RAM and actively being used.

Inactive memory
This information is no longer being used and has been cached to disk, but it will remain in RAM until another application needs the space. Leaving this information in RAM is to your advantage if you (or a client of your computer) come back to it later.

Free memory
This memory is not being used.

You can basically consider all free + inactive memory as free, in essence. The most useful tool to look at is the indicator of pageouts -- this means information is moving from real memory to VM. If the pageouts are rapidly increasing, your computer could do what you're doing more quickly and easily with more memory (either by quitting applications or by buying more RAM).

 

[lugesm]

mkrishnan -

Excellent. Thank you for the comprehensive response to my inquiry.

Now I am a little smarter . . . . maybe . . .