Got problem with Linux memory usage?

If you are coming from the windows world you might wonder about a lot of things while taking your walk into Linux world, as I did. One of the odd things is the way that Linux handles memory. Once a Linux server is up for a while you can notice that the system has eaten up all the available memory, and doesn't let a bit of it go free and you might wonder why you have left less than 10MB of free memory out of 1GB using the "Top" command!
First time I noticed this, it was on a Fedora core 5 with Apache and MySQL so I thought it is a database server thing that also happens on MS-SQL servers but got surprised when I came across the same issue on a different server with the same OS acting as an Internet Gateway, also handling the Inter-VLAN routing for 6 VLANs with small number of clients in each one.
The point is that unless your server is not using its swap space, it is OK. To find out how much memory is actually available, use the "free" command and look at the "-/+ buffers/cache" row.
To figure out how Linux handles memory and relieve the confusion, check the following link:
Linux Memory Management