Forty-odd years ago, Popular Science magazine had an article on a TV called the "Showcase 70". This set was made in 1970 (hence the "70" in the name) and had four monochrome screens plus a large 21" color screen, with a remote that could switch the image from any one of those screens to the large one on a moment's notice; the set also had a digital channel readout, again rather unusual for a TV made in 1970. IIRC, the set was housed in a clear plastic cabinet, which I found unusual, although I guess it makes sense when one considers this was an experimental model.
I don't think the Showcase 70 was ever meant to be mass-produced, as it was simply a prototype that never made it past the developmental stage. However, it could have given other TV manufacturers (Sony, Nordmende, et al.) the idea to produce similar sets under their own branding.
I don't see the practicality of a set like this anyway, except perhaps for TV stations so that they could keep tabs on what the other stations/networks were showing at any given time during the stations' broadcast day (this TV is from the era when television stations would sign off for the night around one or two a. m. local time).
I can't see anyone actually owning a TV like this except for the novelty factor. I had a great-uncle (now long since deceased) who couldn't see the sense, either, in having a TV with more than one screen. He used to say "you can watch only one channel at a time", which makes sense. Even picture-in-picture (PIP) systems, which were popular before DTV and flat screen TVs and showed a small picture from a second channel in one corner of the main TV screen while another was being watched, were useful (IMHO) only for the novelty of them as, again, no one can watch more than one TV program at a time. The PIP functionality only worked when the TV was connected to a VCR with its own tuner.
BTW, no flat-screen TV I have ever seen has had PIP capability. I wonder if this would be possible with HD televisions, or is there some technical or other reason why PIP never caught on in the digital-TV era?
