Let's assume there are 100 channels. That means that if you wanted to
do it with analog technology, VHS, you'd need 100 times the capacity.
Either 100 tapes in parallel (imagine having to synchronize 100 VCRs),
tape rolling at 100 times the speed (tape would wear out, each tape
would last 2 minutes instead of 2 hours, etc), tape 100 times as wide
(lol, just try to imagine that), or a combination of each (twice as wide,
ten times as fast and five in parallel),or of course a better technology.
If you were doing it digitally, mpeg capture, then you'd need a tuner
per channel each capturing at about 1 mbit/s. So that's about 100mbit/s or
about 8 megabytes of video per second. That's not too bad, except you'd
have to fit in 100 mpeg encoders into the system (not that unreasonable).
You might be able to record the whole thing on a computer with a generic
Digital to Analog converter, split it up in software and then reencode in
mpeg, don't know how much processor power / bus bandwidth that would take.
So the answer is yes it's possible but it probably woulnd't be trivial.