Warm standby questions

Hi,

I'm running PostgreSQL 8.3. Suppose I have master server A shipping logs
to backup server B. At some time in the past, I did a full backup from A
to B, and now B is running in recovery mode, happily consuming WALs.

Q1. If I stop and restart master server A gracefully, do I need to do
anything to B (assuming that it doesn't fail over... we'll assume I did
something special to the standby script to tell B not to fail over
during planned downtime of A.) Can B continue happily consuming WALs,
or is another full backup required?

Q2. If I stop and restart backup server B while master server A continues
to run, will B continue eating WALs from where it left off? Or do we need
another full backup? (We'll assume WAL shipping continues successfully during
the time B is down: I'm only stopping/restarting PostgreSQL, not the entire
machine.)

Regards,

David.