This is pretty darned amazing.
I found a CompactFlash to IDE adapter, and a configuration in which it can be put in a Toshiba RD-XS35 DVR recorder. It will start up normally and you can format the CF as its hard drive. It will then record normally, playback normally.
After powering down the recorder I ejected the CF card and popped it into a USB3.0 reader.
Then used IsoBuster
Alpha to "read" the card without mounting it and "Play" the recordings right off the CF flash card. Copy works too.. but IsoBuster
can do both without mounting the card and risking corrupting it.
The CF card I used is a 128GB, kind of old.. but because of its age.. prices have come down quite a bit.. it costs less than a HDD replacement.
This is not a very "robust" solution because I had a few false starts picking equipment that would work (I had failures) when putting it all together. So this is a proof of concept.
After the success with the Polaroid and SD cards up to 128GB I was eager to see if CF would work.. (it "did not
" on the Polaroid.. which is puzzling) so each of these platforms appears to require a special (recipe) so.. there is a good reason its never been discovered before.
But "gosh" darn it.. after messing around with bulky hard drives.. turning one of these classics into an awesome capture machine.. is really neat. Near infinite recording length at the highest speed and quality settings.. no DVD media involved, no PC involved.. until you want to read the recordings off the cards.