A question about postmaster and postgresql commands

Hi!
Can anybody tell me what the difference between postmaster and posgresql is?
More accurately, what's the difference between running the following
commands?

/usr/local/pgsql/bin/postmaster -D /usr/local/pgsql/data >logfile 2>&1 &

and

/etc/init.d/postgresql start


Thanks a lot in advance!

Agustin

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                  Agustín Caminero Herráez

Departamento de Informática         Universidad de Castilla-La Mancha

Instituto de Investigación en       Campus Universitario s. n.
Informática de Albacete (i3A)       02071-ALBACETE (SPAIN)

e-mail: agustin@info-ab.uclm.es     Tlf : +34 967 599200 Ext. 2693
                                    Fax : +34 967 599224

                URL:  http://www.i3a.uclm.es/
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