[CLUE-Tech] Question About Memory

[Matt Gushee]

On Tue, Apr 13, 2004 at 09:53:54PM -0600, Collins Richey wrote:
> On Tue, 13 Apr 2004 15:57:01 -0600
> vbsouthern <vbsouthern at access4less.net> wrote:
> 
> > Question About Memory.
> > 
> > Equipment and OS: Skip down if this stuff is to boring. Computer built
> > 
> > in 1998. P2 Motherboard. Front end bus speed 100.  Two 128 MB memory 
> > chips. Two hard drives: Primary; Western Digital 10G; Secondary
> > Quantum 7.5G... OS: Mandrake/Linux 9.1. Partitioned Primary Drive for
> > OS with 517 MB swap space and secondary 7.5G /home.
> > 
> > It seems that I have a lot of wasted memory. The swap space seems to
> > be empty most of the time while the physical memory is filled with
> > daily usage making the computer slow.
> > 
> > About 100 MB of physical memory is being allocated for DISK CACHE, or
> > in other words it's just sitting there unused. Is there a way to free
> > up more memory on the system? Am I even asking the right questions?

I'm not sure if that's the right question either. I'm pretty sure there
are performance-tuning techniques you can use, but I'm not familiar with
them because simpler measures have always been enough for me: things
like turning off unnecessary daemons (e.g. don't run Apache or
PostgreSQL unless you're actually using them ...), which is of course
good from a security standpoint too; turning off Java in the browser
(could make a big difference), keeping the desktop light. I also usually
compile my own (fairly small) kernels. That used to make a big
difference back when, say, 32M was a lot of memory; these days it's
really not worthwhile building a kernel just for better performance, but
it can still help a bit.

> Others can give you more exact specs, or you can google for information
> about the way the linux kernel handles memory. I'll tell you what I
> know:
> 
> 1) Based on my experience, 256M is a marginal amount of memory for a
> normal linux desktop system;

I guess it depends what you consider "normal."

> 512M is a much better number, particularly
> if you use kde, gnome, full mozilla, open office, gimp, and other memory
> hogging applications. I have a slower (cpu-wise) machine with 512M, and
> I get as good or better performance than this machine with only 256M.

I'm typing this on a Pentium Pro 200 with 196M, and in the normal course
of events it runs just fine, thank you--and I'm *very* picky about the
responsiveness of desktop applications. Now, certainly I run a
lightweight desktop: just plain Window Maker, no GNOME or KDE. Probably
95% of the time I am using either ViM, Mutt, a browser (Galeon or
Firefox), or command-line tools in an Rxvt; I use OpenOffice, but no
more than I have to; the GIMP when I can find the time--no slowdown
there if I'm editing moderate-sized Web graphics; I avoid Java like the
plague. I also tend to run a fairly small number of applications at any
given time; I see people with several dozen windows open at once, but I
don't multitask that intensively myself.

So my case is probably not typical--but I think it indicates that you
don't *need* even 256M, though you may very well want that or more.

-- 
Matt Gushee                 When a nation follows the Way,
Englewood, Colorado, USA    Horses bear manure through
mgushee at havenrock.com           its fields;
http://www.havenrock.com/   When a nation ignores the Way,
                            Horses bear soldiers through
                                its streets.
                                
                            --Lao Tzu (Peter Merel, trans.)