non-stop recording is possible?

["mole" <chromallly@xxxxxxxxx>]

I need to put a 24 hour surveilance camera in my store.  I'd like to
see everyone coming in and out of the back entrance.  Our store runs 24
hours a day.  I don't need multiple camera, just one.  It has to
provide clear picture, black and white is fine.  Most importantly, it
has to be running 24 hours a day, 7 days a week.

Any recommendation?  I don't need a super gizmo, just a simple reliable
one that doesn't break down and low cost.  I rather not use VHS
recorder.

Does anyone know how much I could record in a 80 gig hard drive in
standard TV resolution?  Does it matter if it's black & white or color?