All it is is a hard drive inside the receiver... It continually records what you are watching without you having to hit the record button. (it hold it like the cache of your computer)
But once you change the channel or turn it off it erases what was held in the cache.
So if I have FOX News tuned in (and not actually hitting the record button) then it will be in the cache. So I can rewind back for about 1 1/2 hours if I left the DVR on FOX News.
A DVR can a also record just like a VCR does buy hitting a record button - except it keeps in on the hard drive inside the receiver without rewriting over it until you want it written over.
My DVR hard drive will hold about 120+ hours of recorded shows.
I see, so you can record what is in the cache as long as you were watching it or you can program it to record things ahead of time right? It doesn’t hold things in cache if you were not watching it.