ok so I heard that the new ps3 slim doesn't have this...what is It and what does it do?

Depends on which version you are using.
# G  q, x/ b" w5 u7 {) YBut you can try to use it for th PS3

The Linux OS for the PS3 is an Operating System (like Windows for your PC or MacOS for your Mac). Instead of the graphical interface used on the PS3 out of the box some people install Linux onto the hard drive of the unit. : T& I: D+ g5 k4 y# N
This was mostly done by "tweakers" and other Linux fans who wanted to play around with the Playstation. For 97% of the PS3 market this feature was never utilized and doesn't hold much value to the average person.