My application runs on
OS : Free BSD
Webserver : Apache
Engine : Tomcat 4.0.2

In out typical client requirement,the basic members should not be allowed to login to the site when the server load reaches ( x %) .This variable is set from the admin section.
When we say load x say 80%, that means 80% of memory is consumed at the given instant.I have calculated the memory available to the Runtime and by doing some calculations was able to find FREE MEM,TOTAL MEM, CONSUMED MEM.When the CONSUMED MEM >= Load ie x % of the total memory I disallow basic member login.

Is there anyother way the server load can be calulated...?

The memory available to runtime or the RAM memory is deciding factor.If RAM is then how do we calculate the RAM memory and other details.