Comment by LocalH | Hacker News Reader

Comment by LocalH | Hacker News Reader

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Literally the modern equivalent of the old video-based backup systems. I remember they existed for both the PC and the Amiga. You would load a blank VHS tape into a VCR, connect the output of the computer to that VCR's input, and then tell the program which data you'd like to backup to the tape. It would generate this flashing "mess" of black and white pixels that you'd record to the tape. To restore, you'd connect the VCR output to a little box that came with the product, it would convert the black and white data in the video signal to a data stream that the program would use to restore your data.

A portion of the signal would be used for timing, metadata and error correction, so the program could tell you if the data was sufficiently damaged upon restore.

LGR has a video on the PC version from Danmere: https://youtu.be/TUS0Zv2APjU

Here's a video example of the Amiga industry's take on the idea: https://youtu.be/VcBY6PMH0Kg?t=573

Sony even did this in 1980 to record CD-quality PCM audio onto VHS tape. https://youtu.be/bnZFLzBO3yc

We used to use regular audio cassette recorders to store/restore data on the TRS80 before hard/floppy drives. It's also how you backed up/restored midi data from early synths. It basically just sounded like an early dial up modem transmitting data when you played it back as audio.

https://www.youtube.com/watch?v=-nHrjqmt_wQ

> It's also how you backed up/restored midi data from early synths.

In a weird closing of the circle, I now store the internal sounds backup of my vintage Juno 60 synthesizer as a WAV file recorded from that tape backup output.

So the digital info of the internal synthesizers gets converted to analog audio in the synth, then passed as audio to my modern computer’s audio interface, which converts it to a digital representation of the analog audio.

And vice versa to restore the backup into the synthesizer’s memory.

Incidentally those backups are more reliable now than when using analog tape decks, since one doesn’t encounter physical tape degradation or a cassette deck “eating” the tape.

I haven’t done any testing with compressed audio formats, but I would expect even lossy formats to perform well, if one keeps the lossiness within certain bounds, so that the highest frequencies in the audio file are preserved.

> I haven’t done any testing with compressed audio formats, but I would expect even lossy formats to perform well, if one keeps the lossiness within certain bounds, so that the highest frequencies in the audio file are preserved.

MIDI as a compression format for that kind of audio data would be a lossy way to encode such an audio stream, and it certainly would perform well, so yes, such lossy formats do exist.

Most research in audio compression has been done on compressors that exploit the limits of human perception, though, so of the shelf lossy compressors may not do very well.

Calling midi a form of lossy audio compression is a stretch. Its like saying whistling a tune is a lossy way to compress a song.

Yeah you're transmitting information about the source but to call it lossy is an understatement.

> It basically just sounded like an early dial up modem transmitting data when you played it back as audio.

Modern synths still do this. The Korg Volca has a library for converting audio into white noise that reprograms/adds more samples.

My Apple ][+ had a tape interface. It mostly worked - if the tape stretched or if the tape speed changed for some reason (dirty capstan, power supply fluctuations, low volume, high volume, evil pixies) then you wouldn't be able to read it back.

This site describes the format, which was basically a header tone, a sync tone, data bits, and then a checksum (not described there but other sites say it was just an XOR). When we got a Disk ][ (5-1/4" floppy drive) all those issues went away.

http://www.applevault.com/hardware/apple/apple2/apple2casset...

How you loaded games onto my Spectrum 48k, had to make sure the volume on the output wasn't too high or too low. I could guess it had a bandwidth of about 2-3kbit from how long I think it took to load (nearly 40 years ago)

It varied with the content - a zero had a high-pitched tone and took half as long to transmit as a one - but it averaged out at around 1800bps.

Certain things had really distinctive sounds, like loading screens. I could recognise Manic Miner loading from just about any ten second chunk.

Atari too; and god they were unreliable. But cheap!

There was also DVStreamer for Windows and other tools for other platforms which would store data on MiniDV tapes. This is of course a bit less interesting than storage to VHS, since MiniDV was already storing a bitstream, but still a clever oddity. I think you could store ~13.5GB in SP mode or 20GB in LP mode (reduced error correction).

Or the audio based ones like this Commodore cassette as stage device. A guy in my neighborhood had one as part of Pac-Man contest winnings.

https://en.wikipedia.org/wiki/Commodore_Datasette

Had one of these with my C64. When my floppy drive broke down, I actually ended up ordering a copy of "Silent Service" on cassette from someone in Great Britain. It kept me sane while I saved for the floppy repair.

I had one in the late 90s that used 8mm tapes and my video camera in the same way. Could store a ton of stuff.

It was pretty finicky, though, and very slow.

I just had a flashback to the Nintendo e-Reader I had as a kid.

Black and white dots in a strip on a card. Swipe the cards to load the games.

While never popular as backup devices, VHS and larger helical scan tape formats were used in a number of interesting niche data storage applications.

Here, for example, is a ruggedized S-VHS data recorder built for military and aerospace applications:

http://www.thic.org/pdf/Jul97/metrum.cduckling.pdf

Minor nit - the Sony PCM adaptor worked with a Betacam deck. My parents did a documentary in the late 80s where almost all the original music for the soundtrack was recorded with a Sony PCM-1 and SL-F1. I wish I still had the masters for it.

I’m sure it would work with any recorder that could record a sufficient quality signal. It was just NTSC video.

Beta had a slightly high bandwidth but probably not enough to make a difference.

These days you get four channels of 96kHz 20-bit audio in a wee box the size of a Betamax tape, with hours and hours of recording on an SD card. That physical size is mostly a function of needing half a dozen XLR connectors on it and a big enough screen to see what you're doing.

This was once very common: https://en.wikipedia.org/wiki/ArVid

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