About | ACP | Buy | Industry Watch | Learning Curve | Search | Test Drive
Home » Industry Watch » The Technological

Flush to Disk

It takes all kinds.

Get It

Try It

1. There are no 'swap files' in OS X (Unix) and there never have been.

$ ls -al /private/var/vm
total 8519680
drwxr-xr-x   4 root  wheel         136 Nov  3 01:40 .
drwxr-xr-x  28 root  wheel         952 Feb 22  2012 ..
-rw------T   1 root  wheel  4294967296 Nov  3 22:41 sleepimage
-rw-------   1 root  wheel    67108864 Nov  3 01:40 swapfile0


2. There is true virtual memory which is used regardless of the amount of RAM.

VM doesn't have to have anything to do with swap. Virtual memory is a matter of page tables etc. Oops again.

3. Peter Cohen must be a Windows NT guy where they continue to use brutal inefficient and seriously outdated swap file technology.

No Andre, Cutler's NT starts a session by allocating swap for all RAM and a bookkeeping area. It's Cutler's system that maps nothing into memory (frames) until it is needed (pages) and that is why the APIs for process creation can claim they complete almost instantaneously.

If you knew anything about Unix, you'd know the original purpose of the 'sticky bit'.

The sticky bit was introduced in the Fifth Edition of Unix (in 1974) for use with pure executable files. When set, it instructed the operating system to retain the text segment of the program in swap space after the process exited.
 - Wikipedia

4. VM is dynamically allocated the computer will slow when short of RAM. [sic]

No again. VM has nothing to do with swap. VM is always used. Otherwise you'd be stuck with beige boxes and IBM 5150s.

Flush to disk.

About | ACP | Buy | Industry Watch | Learning Curve | Search | Test Drive
Copyright © Rixstep. All rights reserved.