Do Computer science engineering students get a job in PSU?

I am a final year computer science engineering student from Tamil Nadu, I need some advice on my career. I have some doubt on selection of job.
1. which job should I go for government job(IBPS, Public sector, TNPSC) or private job(TCS,CTS,etc..) ? which is safe?
2. Is there is any chance to get into PSU ?
3. If yes, what is the procedure ?
4. In what way GATE exam is useful for me ?