[HN Gopher] Audio tape interface revives microcassettes as stora...
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Audio tape interface revives microcassettes as storage medium
Author : rcarmo
Score : 27 points
Date : 2021-10-20 09:16 UTC (2 days ago)
(HTM) web link (hackaday.com)
(TXT) w3m dump (hackaday.com)
| LesserEvil665 wrote:
| I remember 6/7-year-old me begging my father for a tape deck to
| use with CoCo3. He refused, saying they were too expensive.
|
| Were they really in the early 90s? I doubt it. I lost interest in
| writing basic on that thing since I couldn't save programs.
|
| Anyway, I fully intend to try this out if only to close that
| loop.
| tyingq wrote:
| The "ready to use" one with the 5 pin DIN connector/adapter was
| probably expensive.[1] Otherwise, he would have had to find an
| adapter or fiddle making one himself. And even that would
| require a cassette player with all the right jacks (mono in,
| mono out, remote). They didn't all have those.
|
| [1] This thing:
| https://colorcomputerarchive.com/repo/Documents/Manuals/Hard...
|
| Edit: An old ad...$59.95 Or $142 if inflation adjusted to 2021
| from 1987.
|
| http://www.trs-80.com/images/desc/desc-cat-rs-26-1208.jpg
| sedatk wrote:
| I had a similar experience with disk drives. They were too
| expensive, so I had to stick to the built-in tape unit of my
| Amstrad CPC464. I could save programs, which made a huge
| difference, but tape was very limited in capability. For
| example, I couldn't write programs running other arbitrary
| programs, or programs working on databases. What I wrote was
| very limited in utility, usually games. Even running an
| assembler (which I got to hold on very late anyway) was a quite
| complicated process on tape. Now, after reading your story, I
| can't imagine being even without a tape. I at least managed to
| learn BASIC and Z80 Assembly with just a tape.
| LeoPanthera wrote:
| Microcassette, despite being best known for use in answering
| machines and voice recorders, was briefly a pre-recorded music
| format. There was even a microcassette deck component you could
| put in your hifi.
|
| A video about it: https://youtu.be/ZZYpPlpD3ow
| p1mrx wrote:
| I wonder what the maximum bitrate of an audio cassette is, using
| modern encoding techniques like OFDM with error correction? I
| searched once, and saw estimates in the 25 kbps range, but no
| usable implementation.
| sprash wrote:
| I was able to fit about 60 MB per channel on a 90 min audio
| cassette [1]. The bias frequency of that particular deck was
| about 60 kHz. This means bypassing the recording circuitry
| could lead to much higher data rates.
|
| 1.: https://news.ycombinator.com/item?id=28193079
| LeoPanthera wrote:
| The sound quality of an audio cassette is at least as good, and
| almost certainly better, than the quality of an analogue
| telephone line. So I bet you could set a lower bound of at
| least 33.6kbit/s, since that was as fast as telephone modems
| went.
|
| 56k modems relied on your phone line being digital after the
| switchboard, but I would imagine that 56k should be doable as
| well.
| Const-me wrote:
| Not sure it's directly comparable. When modem flips one bit,
| the CRC checksum in IP packet becomes incorrect, someone
| drops the IP packet, the condition is detected and the packet
| is re-transmitted. This slows down things substantially but
| user still gets their data. I think tapes need more
| reliability because there's only 1 try.
| p1mrx wrote:
| I wouldn't automatically assume that tape is better than a
| phone line. For instance, a phone line will always clock at 1
| second per second, because everything runs in real time with
| no storage.
| LeoPanthera wrote:
| I can't imagine that clock recovery would make a huge
| amount of difference.
| squarefoot wrote:
| I did something similar in the early nineties by using the
| venerable AM7910, an old modem chip often used in vintage
| computer and Ham Radio gear, to make an interface to store and
| retrieve data on tape from my Amiga 500. I used a normal cassette
| deck for storing, but the chip was really slow at 1200 bps, even
| for an old system like AmigaOS, and per data sheet it didn't
| offer higher speeds, however I tried anyway to change its clock
| frequency by testing a few Xtals in place of its 2.4576 MHz
| standard one, and eventually settled to an old PAL color TV Xtal
| (4.433619 MHz) that would nearly double the speed without
| introducing errors. Good old times...
| fnord77 wrote:
| I remember data storage on regular cassette tapes was painfully
| slow.
| kabdib wrote:
| I used audio cassette for a few years (1978-1979) on my home-
| built Z-80 system.
|
| Upgraded to a wacky cassette transport called a Phi-Deck. It
| was faster and had automated head control and seek; you could
| do a real file system on it. 9600 baud equivalent, for the
| setup I used; could get 100K or so on a cassette if you were
| patient.
|
| https://bytecollector.com/dg_phideck.htm
| hellbannedguy wrote:
| Those were great little recorders. Pricy, but good. I bought one
| from a guy at work for $190. He paid $269.00
|
| They are extremely well made. It still works today.
|
| I think he was trying to get our possed boss to say something
| incriminating.
|
| I didn't have the heart to tell him being a a-hole in America is
| legal.
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