Personnel Action, pinch...

Hi all

Can anybody explain

1) What is personnel action?

2) What is feature "PINCH"(Administrator Group?)

3) What is igmod feature, which purpose?

4) What is cluster, what are RT table and CRT table?

5) What is pay slip, where u will create-related?

6) What is igmod feature, which purpose?

thanks and regards

Sanjay