[Info-vax] OpenVMS I64 V8.1 "Evaluation Release"?

[Paul Sture]

On Thu, 22 Mar 2012 22:33:26 +0000, glen herrmannsfeldt wrote:

> As far as I know, web browsers don't make especially good use of virtual
> memory. I sometimes use either a Win2K machine or a Mac PPC/10.5.8
> machine, both with 1GB real memory and plenty of swap. The Mac is
> especially bad, and Firefox is worse than Safari, in the use of memory.
> After not so long the Mac is swapping on every link. I then exit,
> restart, and use the "reload previous session" link to get back to where
> I was before. Somehow they keep too much old stuff in memory, and not
> such that it can stay swapped out.

What version of Firefox are you using? Recent releases claim to have 
address the memory footprint problem (though if you are still on PPC you 
might be outta luck).

OS X allocates swapfiles on the fly, and attempts to deallocate them when 
no longer used.  The algorithm has changed slightly with various 
releases, but large swapfile usage is something to watch out for.

Back in OS X 10.4 on a 640 MB iBook I found that if the total swapfile 
space got above 1GB things would start crawling to a halt.  Quitting all 
apps and leaving it for a while was one solution, but that didn't always 
work ("some process" was presumably still mapped to the higher addresses 
within swapfile space).  Logging out then back in again was usually 
sufficient to persuade OS X to reclaim swap file space by deleting the 
latest created files.

To monitor swapfile space on OS X (the following done on PPC 10.5.8 with 
1.25GB RAM)

ls -lh /var/vm
total 1048576
-rw------T  1 root  wheel    64M Mar 20 11:41 swapfile0
-rw------T  1 root  wheel    64M Mar 20 23:47 swapfile1
-rw------T  1 root  wheel   128M Mar 20 23:47 swapfile2
-rw------T  1 root  wheel   256M Mar 20 23:48 swapfile3

or:

du -h /var/vm
512M	/var/vm

After logging out and in again:

ls -lh /var/vm
total 524288
-rw------T  1 root  wheel    64M Mar 20 11:41 swapfile0
-rw------T  1 root  wheel    64M Mar 20 23:47 swapfile1
-rw------T  1 root  wheel   128M Mar 20 23:47 swapfile2

If I were to do a reboot, I'd expect to see only the first one of those, 
at least until I start running apps.

-- 
Paul Sture