Determining the version ..
 

Hi All,

the command uname -r returns 2.4.21.-37a8

and /etc/redhat-release displays RHEL WS rel 3 (Taroon Update 4)

Is the output of uname -r - kernel version ?
What is Taroon Update 4 ?

Uname -r returns your kernel version, 2.4.21. The extra bit is a customized message you can add when you compile it.
Taroon is just the name for RHEL 3. You can ignore that bit, nobody needs it. And you're using update 4.

Yes, "uname -r" shows the kernel version. Taroon is the codename for RHEL 3.x and update 4, means you are running service pack 4 for RHEL 3.x.