Hi everyone,

I just installed a RedHat 9 server where on the components selection, i choosed to install Development tools and removed Text based internet, Windows File Server and another one i cannot remember but definitely not needed in my configuration.

I have a Celeron 300 PC w/ 64 MB memory. Partitioned my 4 GB hard disk to 100 MB of /boot partition, 128-256 MB swap and the rest for /. I used this PC as a RAS server and installed an Equinox SST adapter w/ a 16 port module but as of now we're just using 8 ports bec. i'm currently sizing up the server. I installed mgetty included in the RedHat 9 CD and ppp-2.4.3.

Here's the question: I noticed that w/o any load or dialup connections my free memory is about 32 MB. After 8 dial up connections are accepted, the free memory reduced up to 8 MB and while the connections are released the 8 MB free memory does not change. But after i restarted Linux the free memory was back to 32 MB.

Is this behaviour natural on Linux or for PPP only? How does Linux utilize/manages memory?

from: http://sourcefrog.net/weblog/softwar.../free-mem.html
(google is your friend)

"The short answer is that you should never worry about the amount of free memory on Linux. The kernel attempts to keep this slightly above zero by keeping the cache as large as possible. This is a feature not a bug."

Thanks, is this true also for Unix? Since Linux is a clone of Unix?

No, this is not true for "unix in general"

Historically (System V/BSD) Unix uses a "fixed" buffer size (compiled into the kernel or configured on bootup). Modern unix variants and AIX are able to allocate buffer cache dynamically.