two methods to start postmaster

I am puzzled on the supposed two methods of starting postgres--"pg_ctl
start" and "service postgresql start". Below is my understanding. It
would be great to have some clarification on them.

My confusion stems from when I first intitiated postgres by creating the
database cluster with "initdb". I am positive that I had to perform both
commands to get everything working, "pg_ctl start" as the postgres user
and then "service postgresql start" as root.

If I understand this correctly
using the command "pg_ctl start" starts postmaster but the process (ps
ax | grep post) is listed as /usr/bin/postgres

using the command "service postgresql start" starts postmaster but the
process (ps ax | grep post) is listed as /usr/bin/postmaster -p 5432 -D
/var/lib/pgsql/data

And both are the same thing?

Thanks

Marc Fromm
Information Technology Specialist II
Financial Aid Department
Western Washington University
Phone: 360-650-3351
Fax: 360-788-0251