When shooting with the DVX100a (30p), how many minutes per gig do you get if recording directly to hard drive or digitizing footage from tape?

I'm pretty sure that you use just over 13gb for every hour of footage.

Yes, that's right. Approximately 4.5 minutes per GB.

It varies on codecs, but here is what I use as a reference.

DV=~3.46MB/S
1 Min=~ 207.6MB
5 Min=~ 1038MB
1 Hour=~ 12456MB

Also consider that you want a little "breathing room" on your hard drive. Personally I like to use 15GB/hour as a number which takes this into account and makes the mental arithmetic easier.

Or, since the thread is titled "Minutes per Gig" and that's what Greg asked for, that would be:
Laurence: 4.8 Minutes per Gig
Boyd: 4.0 Minutes per Gig
Dan: 4.5 Minutes per Gig
Take yer pick.

Thank you all. Just got a 300 gig external so I don't think I'll hit 20 hours of footage at any given time. I edit with Digital Beta footage at work but our Adrenalines have 500 gigs (not including Unity) and I can can pack about 4 half hour shows on the system at 20 to 1 with each episode having about 20-32 minute tapes digitized. I actually never pay attention to what I get per gig but I think I'll check it out. Thanks again...