Audio Cassettes: One Hole?

[Speakeasy]

Recently, while searching the internet, I came across a couple of images of "square" audio cassettes. While I readily acknowledge being a techno-peasant today, I was pretty much up-to-date when audio cassettes were introduced and I do not remember a square format which, I assume, would have required a separate player/recorder.

Two of the images below show a square cassette having one spool which would seem to support the notion of a separate player/recorder. The third image shows a square cassette with two spools which would not have fitted into a regular cassette player/recorder. If such a format did indeed exist, I would imagine that it would not have been destined for wide use by the general public. Perhaps it was a proto-type of what became the rectangular cassette or perhaps it was for use in computers of the era? The images are not of the ill-fated Sony 8-track cartridges either.

Then again, perhaps these photos are a hoax. Would anyone happen to have any information?

EDITED:
Tinkering
Titled changed from "Square" to "One Hole"

[dgc1970]

Maybe contact this guy, he seems to be a bit of an expert:

https://www.youtube.com/playlist?list=P ... PsbA1Cl2RI

[Speakeasy]

Recently, I came across a 40-page booklet entitled “Compact Cassetten Report: Philips Einloch-Kassette vs. Philips Compact-Cassette” by Uwe H. Sültz wherein the author explains the history of the one-hole (spool) and two-hole (spool) compact audio cassette technologies which were developed by Philips Recording Industries in the early 1960’s. Both systems used the same 3.81 mm wide magnetic recording tape.

Philips One-Hole versus Compact Cassette.JPG

The one-hole (spool) cassette was developed by Philips research team located in Austria. Although it had some initial success as a medium for dictation machines, a second cassette was required as a pick-up spool in a manner similar to the larger and less portable reel-to-reel magnetic tape recorders of the era. The two-hole (spool) cassette was developed by Philips research team located in Belgium. Owing to the advantages of the two-hole (spool) compact cassette – it was more compact than the one-spool cassette and it incorporated the pick-up spool into the same cassette housing -- the one-hole (spool) cassette was not released to the public.

Compact Cassetten Report: Philips Einloch-Kassette vs. Philips Compact-Cassette – Amazon.co.uk
https://www.amazon.co.uk/dp/B071DH9Y21/ref=rdr_kindle_ext_tmb

It goes without saying that I have ordered a copy of the above-mentioned booklet.

EDITED:
Tinkering.
Formatting.

[Speakeasy]

I received my copy of “Compact Cassetten Report” by Uwe H. Sültz today, wherein the author recounts, on two brief pages, the development of Philips’ one-spool and two-spool audio cassettes. The remainder of the small booklet is composed of colour photographs of various prototypes. Based on the concept by which reel-to-reel tape recorders function, the one-spool cassette required an empty pick-up spool to receive the played portion of the magnetic tape. However, in the case of the one-spool cassette, the pick-up spool formed an integral part of the recorder/playback machine itself. The author notes that the one-spool cassette permitted one-sided recording only. The double-spooled cassette, which also permitted double-sided recording, and which was more compact than the former, won the competition. An interesting historical note is that, during the development of this technology, both American and Japanese recording companies had been approached with an offer to participate in the project but spurned the idea as being impractical and of doubtful commercial success! I have appended, below, a photograph of an opened one-spool cassette showing its interior.

Philips Einlochkassette.JPG