CPU Usage

[Mac attack]

When I monitor my CPU usage there are four different categories:

Wired
Active
Inactive
Free

Can someone please explain what they are? ie whats the difference between 'inactive' and 'free'.

Thanks

[JerryB]

According to this -
http://homepage.mac.com/simx/mughelp/English/f aqs.html

Wired memory is memory in use that absolutely has to stay where it is, ie., the system cannot be allowed to dump the memory out onto hard disk, so that some other program can use it.
Active is data in memory in use by a program, but could be swapped out if necessary.
Inactive is memory that has data in it, but it's not in use by a program, ie., the last program to use it didn't bother cleaning up after itself.
Free is probably memory that has no data in it at all, I would guess.