Where was the computer skill split up into operation, programming and hacking?

I just joined a MechWarrior group that uses the old 3rd edition books. I was handed a PreGen from the core book (The Federated Suns Technician)1, which lists the "Computer" skill.

However, during play, I was told that in some later book (still in the 3rd edition) that skill had been split up into "Operation", "Programming", and "Hacking". Which book is that skill-split in, and does that book also contain a rule on how to adapt a character that was made without that book?

1 - MechWarrior 3rd Edition (FASA #1715) (1999) p. 70/71.