Question on concurrency controls

Hello:

I'd like to learn a bit about how concurrency control is managed by
PostgreSQL, for a project I'm starting. I looked over the documentation,
FAQs, features lists, etc. on the postgresql web site but they are aimed
more toward users and application programmers than tech-heads who want to
look under the hood.

I'm just wondering (a) what scheme(s) PostgreSQL uses (eg. two-phase
locking, timestamp, etc.), (b) what recovery procedures are available, and
(c) what source code modules I should concentrate looking at to see how
these controls have been implemented.

Thanks in advance.

--------------< LINUX: The choice of a GNU generation. >--------------
Steve Frampton <3srf(at)qlink(dot)queensu(dot)ca> http://qlink.queensu.ca/~3srf