Configuring postmaster to use all available memory

Hello Psqlers,

I have noticed that postmaster usually doesn't take up that much
memory.  I'm glad it is coded for efficiency, but, I have it running on
a dedicated machine which does absolutely nothing more than allow me to
log in via ssh and run postmaster.  I want postmaster to consume
basically all available RAM, so any query which is a read (not an
updating query) shouldn't have to touch disk at all.  Is there a way to
do this?  I looked at the -B option, and set it as -B 1024 but it didn't
seem to do much.  Should I crank it further up, or are there other
things to do?

Thanks!