Three newbie general questions about DVRs

[WiseMagic]

1) Do most DVRs come with a hard drive?

2)After recording a program to DVD, when you want to record a second program, does the recording start at the point where the first recording stopped or would it rerecord over the first recording?

3)If you only have 30 minutes of record time on a DVD and you try to record a 1 hour program, will the DVR indicate that there is not sufficient space or time left on the DVD?

Thanks for any help!

[Frobozz]

1) My guess is most do not have hard drives although I've never counted them.

2 & 3) I'll only answer for my Pioneer unit. It has an "optimized recording" option that automatically lowers the recording quality to fit a timer recording on the remaining space, if necessary. It has an "auto replace recording" (hard drive only) option that will replace a previous episode of a TV show recorded with the timer with the new episode. It has a "recovery recording" option that automatically records to the hard drive when the DVD was selected as the destination although a recordable DVD is not in the drive.

Nothing automatically records over content recorded to a DVD-RW.