Memory (RAM) problems?

["Carlos Bustamante G." <carlosb@fisica.ciencias.uchile.cl>]

Hi, I'm a litlle worry about the memory (RAM) used by my machine. 
I'm using slink ( recompiled kernel 2.0.36) and recently I realized that
I have my memory full very frecuently, even when running only a few
programs. Actually, the buffer and the cache use a lot of memory. 
I have 256 Mb, and a typical (not the most terrible) output of 'cat
/proc/meminfo ' looks like :


        total:    used:    free:  shared: buffers:  cached:
Mem:  263127040 221241344 41885696 47808512 95961088 79933440
Swap: 133885952   286720 133599232
MemTotal:    256960 kB
MemFree:      40904 kB
MemShared:    46688 kB
Buffers:      93712 kB
Cached:       78060 kB
SwapTotal:   130748 kB
SwapFree:    130468 kB


Sometimes, there are a release of memory (e.g. when I run a heavy
process) , but the cache an buffer slowly increase  
their memory usage.
Is it normal, or I have a serious problem? Maybe a not well tuned
kernel? Is there a way to release the memory used by the buffer and/or
cache? 

thanks
carlosb