[CentOS] why is this machine using swap space?

Fri Jul 21 15:05:12 UTC 2006
Larry Vaden <vaden at texoma.net>

Mem:   2075040k total,  1331452k used,   743588k free,    50896k buffers
Swap:  2031608k total,      144k used,  2031464k free,  1191532k cached

SunFire X2100 running Centos 4.3.

Linux maytag1.texoma.net 2.6.9-34.0.2.EL #1 Fri Jul 7 19:24:57 CDT
2006 i686 athlon i386 GNU/Linux

rgds/ldv