Process management!

[russell23]

Hi, I am new to Mac and was previopusly using Linux.

I am not pretty sure how the processes are being implemented in Mac OS X Leopard.

Because, when I type
>uptime in my terminal I am getting 2 users logged in in my mac.

But, to my surprise, this number of users seems some relation with number of terminals opened.

becuase, whn I have 4 terminals opened, I was gettibng four users logged in in my MacBook Pro.

Could any Mac experienced user shed some light for me to understand the process management in Mac OS X.?

Thanks in advance.