[Axel]

This problem is really starting to bug me. Every now and then, while using my TiBook 800/512/40 Go, the system slows down for a few seconds, I also may get the spinning wheel, and I lose about 500 MB of disk space. Just like that. The worst thing is, it doesn't necessarily happen while using complex apps, or working on large files.
The problem is, I keep about 1.5 GB of free disk space on my system, so whenever I lose such big amounts, I have to restart the computer or else the system might go crazy with that little space left. Logging out and back in only restores a fraction of the lost space.

Is buying more RAM my only option ? How come I need to restart so often to get back my disk space ?

Thanks in advance for your answers

[SMacTech]

What apps might you be using when this happens? Do you use BitTorrent? I would run top and look at how much VM you are using and if it swap space consuming your hard drive space.
I doubt that the problem is low RAM memory, as 512mb should be adequate for the average user.

[Axel]

I do use BitTorrent, and I think it happened a few times while running it. But I'm pretty sure it also happens with regular apps, like Mail or such.
FWIW, here's the output of the top command (I went from 1.05 GB to 660 MB just before my first post, and I didn't use the computer since then) :

Code:
Processes:  58 total, 2 running, 56 sleeping... 178 threads            21:05:00
Load Avg:  1.02, 0.59, 0.45     CPU usage:  81.6% user, 18.4% sys, 0.0% idle
SharedLibs: num =  120, resident = 24.1M code, 2.43M data, 6.28M LinkEdit
MemRegions: num =  8936, resident =  201M + 6.38M private,  115M shared
PhysMem:  65.1M wired,  181M active,  218M inactive,  465M used, 46.8M free
VM: 4.15G + 81.9M   101762(0) pageins, 87433(0) pageouts

  PID COMMAND      %CPU   TIME   #TH #PRTS #MREGS RPRVT  RSHRD  RSIZE  VSIZE
  798 top         10.7%  0:03.14   1    16    26   328K   364K   704K  27.1M 
  793 ICQ 3.4      4.5%  0:40.00  10   341   266  5.42M  16.4M  26.0M   140M
  788 Adobe Phot   0.5%  0:31.99   4    89   620  45.1M  47.5M+ 81.8M   259M
  786 Preview      0.0%  0:07.46   3    75   143  1.93M  7.16M  15.3M   117M
  726 httpd        0.0%  0:00.00   1     9   144     0K   316K   156K  53.8M
  725 httpd        0.0%  0:00.02   1    10   144     0K   316K   172K  53.8M
  724 httpd        0.0%  0:00.01   1    10   146     0K   316K   168K  53.8M
  664 tcsh         0.0%  0:00.20   1    13    30   508K   656K   752K  22.1M
  663 login        0.0%  0:00.03   1    13    37     0K   256K   204K  26.9M
  662 Terminal    49.0%  0:49.26   5    71   161  1.91M+ 6.77M+ 13.7M+  110M 
  515 Safari      29.2% 34:22.68  11   298  1172  77.6M  28.7M+ 83.6M   316M
  514 Mail         0.0%  7:53.86  10   152   330  9.96M  15.9M+ 35.7M-  176M 
  501 AppleSpell   0.0%  0:00.04   1    24    33     4K   732K   652K  35.8M
  397 Meteorolog   0.0%  0:55.99   6   223   297  20.6M  7.76M+ 20.1M   149M
  396 iCalAlarmS   0.0%  0:00.72   3    68    97   576K  2.07M  6.44M  94.9M
  395 LaunchBar    0.0%  1:44.74   3    94   209  5.67M  6.78M  19.7M   126M

[JKT]

It sounds to me as though what is happening is that you are generating too many swapfiles. What is happening when this occurs is "paging" of the contents of RAM to the hard drive as swapfiles (hence the slow down to the system - the read/write process is relatively slow). In 10.3.x, Swapfiles are generated progressively as 64MB, 64MB, 128MB, 256MB, 512MB, 1GB, 2GB, etc sized files. I suspect that you are occasionally having to create that 5th swapfile. There are two problems for you here - the first is that you probably need more hard disk space and the second is that you don't have enough RAM to avoid generating that 5th swapfile. I would try removing some files from your hard drive (you can get by with what you currently have remaining but it is going to continually impact upon your Mac's performance) and I would also highly recommend more RAM. Also, you might want to consider upgrading to a larger, faster RPM hard drive - the faster RPM will reduce the impact of swapping as it will occur faster.

Restarting reclaims your disk space because the swapfiles are temporary and dynamically created and destroyed. When you restart, you will have only the first 64MB swapfile (unless you load a lot of apps at login, in which case you may generate more swapfiles).

To check what swap files you do have created, in the Finder press command-shift-g and type /private/var/vm in the dialogue that appears, then click Go - this will show you your hidden virtual memory directory and its contents.

[yongfook]

I notice you have photoshop running...could it be your photoshop scratch disk?