40 years later, a game for the ZX Spectrum will be again broadcast over FM radio
racunalniski-muzej.siI sometimes mention that our radio used to broadcast games you could tape off the air to young people and they fail to grasp the futuristic glory I experienced when I explained to myself it's like one-way modem.
Honestly, I miss teletext so much. I was my primary news source until it was in practice abandoned.
It was so nice. No pictures at all. Just text of different sizes and block art. And the wait time made you read in order once and not 'doomscrool'.
The limited text length forced the writers to keep it short.
My point being, one way coms are underrated.
In The Netherlands the teletext system of the Dutch public broadcasting system does still exist and has a loyal following. It's also available on the web [1] and as a mobile app.
Even nowadays I still use it a lot myself for a quick catch up of the news. Some of the benefits: - Since space is limited, the news stories are ultra short and to the point - No ads - No "related stories" - No toxic comment sections - No misleading 'thumbnails'
It doesn't take longer than a minute or two to catch up on the most important stories.
For Americans, the closest would be:
gopher://magical.fish/1/news
same as above, but for proxied to the web:
https://gopher.floodgap.com/gopher/gw?a=gopher%3A%2F%2Fmagic...
If you are so inclined, ARRL transmits amateur radio news bulletins daily on a regular schedule[1] in the USA. The bulletins can be received with any shortwave radio that supports SSB (single sideband modulation) and decoded with a soundcard and appropriate software. Obviously, it's considerably different content, but if you are looking more for the experience of receiving and decoding a radio text bulletin, you can certainly have it! Many other teletext services[2] exist as well.
A friend of mine had faulty wiring in his house, the electricity would go out for a few brief moments whenever someone would ring his house bell. He would stand in front of his house when ZX Spectrum games were being broadcast so nobody would ring and interrupt his recorder :)
For me it was my mum turning on the vacuum cleaner would cause a spike that could reboot the Spectrum 48K. The 128 model had a better power supply as I remember. Also the ZX81 I had before that (think I was 8 at the time) was extremely sensitive to the state of the current in the house...
This is so great!
Reminds me of policing the phone line so someone didn't blow up my BBS Kermit downloads.
This triggers a lot of nostalgic feelings. We also had that in Belgrade during 80s, in a radio show hosted by late Zoran Modli. I even recorded some of emmited games although I didn't have a computer at a time. Access to software, music, or any kind of information was hard, slow, and limited back then.
Hats off to Žiga Turk and Moj Mikro magazine. That one along with Svet Kompjutera and Računari was the main source of IT knowledge for hungry minds in ex Yugoslavia.
Nostalgic feelings is what we have been going for. We have a large amount of (also scanned) issues of Slovenian and ex-Yu magazines in our collection: https://zbirka.racunalniski-muzej.si/revije/
Eh, I had all the issues of Moj Mikro while they were publishing in Serbo-Croatian, as well as all the issues of Svet Kompjutera, Računari, and PC until around 2007-2008 (Računari ceased publishing a few years later). They were all carefully packed in the basement until my mother decided to throw them all away, as who needs old stuff?
And I was planning to spend my retirement days playing with the ZX Spectrum and reading stuff that I immensely enjoyed as a kid. Tough luck :)
There are scans of these old magazines at archive.org
Žiga Turk was (at a much later time :)) also the minister of education, and he's a university professor. Just shows you that game developers can get far in life :)
I fondly remember the Pete Shelley album “XL-1” which had a final track that contained a spectrum program.
You dropped the needle on the record and pressed ‘Run’ simultaneously and it would display an animated set of patterns in sync with the music - and the song lyrics
For those curious: https://www.youtube.com/watch?v=YhKQy580STQ
Fascinating, here's the story from the programmer:
I'm not sure why he felt he had to write it all in machine code though, sadly he doesn't discuss that decision. Perhaps it was due to the time-dependency of the lyrics?
Without knowing the specifics of that platform, it is likely that the BASIC interpreter was not fast enough to generate the desired effects and animations.
My guess would be quite simply to overcome memory constraints
The user manual is also quite awesome :) Here's the bit about copy protection (translation is mine):
Programs cannot be copy-protected successfully. KONTRABANT 2 is protected only insofar as not just anyone can look at its databases. Therefore you could copy it to whomever you wish.
Know that by doing so you will be nipping Yugoslavia's young software industry in the bud and hurt us, the enthusiasts who are writing it. You will also be hurting yourself. Programs will become more expensive due to smaller sales or won't come to exist in the first place.
Copying programs is hurting everything ALL of us computer folk have fought for. We've already achieved that anyone can buy a modest computer legally without humiliating themselves at a border crossing while YOU can help us breathe our local soul into these machines.
..and in the troubleshooting section:
Don't forget the first law of computer science: "Is it turned on?"
Back in the day, there were magazines that had a flexible plastic LP/single (aka 'vinyl'), that you'd play on your stereo, and record to cassette, and load into the computer.
Coincidentally, it's this - https://www.youtube.com/watch?v=1FePROXUG6E
Me: going through the racks of magazines trying to find a record without a crease in it.
Yes!
For those far away from Slovenia, is the broadcast available over the internet (I know, I know)? This link says it's not available because of "regional restrictions":
https://tunein.com/radio/Radio-Student-893-s25182/
Edit: Found a working link: https://onlineradiobox.com/si/tudent/?cs=si.tudent&played=1
You can also listen to stream directly on website https://radiostudent.si/
http://kruljo.radiostudent.si:8000/ is the official stream
For something a bit more authentic, find a WebSDR that is located somewhere in or close to Slovenia :)
How well does this work with lossy compression? I would trust only lossless formats and analog with digital data encoded as audio, but I have zero hands-on experience with this
The bit rate of a speccy tape recording was only about 1500 bps, and we routinely recorded on the cheapest tapes, and tape machines that were little better. I'm sure it'll be fine.
Technical details for those interested: https://sinclair.wiki.zxnet.co.uk/wiki/Spectrum_tape_interfa...
Minimodem at 300BPS with the audio encoded to OPUS at 64 KBPS makes pretty reliable dumps with a relative small space per hour (~30MB).
Back in the eighties the Dutch radio network NOS broadcast programs for all types of home computers. They even invented a common BASIC dialect for this to work: BASICODE https://archive.org/details/BASICODE2Manual This was sent on AM, so it was available in other European countries as well.
I'd like to have a listen to those waves and I'm not in Slovenia, any source on the internet?
Edit: Found a short sample of a Commodore Datasette program on Wikipedia[0].
It's a bit before my time, and tape based games never really caught on in the US as far as I'm aware, but I've always been kind of fascinated by storing programs in audio.
There's something bizarrely cool about the idea of taking something designed for an analog medium and using it for something sort of definitionally not analog. It was traditionally cassette tapes, but I saw a YouTube video where some companies distributed games on CDs, and there's something kind of weird and anachronistic about being able to play a ZX Spectrum game off a CD; the program is going from Digital (being written) -> analog (converted to audio signals) -> digital (put on a CD) -> analog (back to audio) -> digital (read by the computer). People can be pretty clever sometimes.
Dialup modem did the same thing but with more efficient protocol and error control via a network stack. ADSL also took a step further and used the shielding on copper cables to attain higher (inaudible) frequencies. The tech in some form is still about this is just the granddaddy version :D
ADSL does not depend on shielding of copper. It uses Discrete Multi Tone modulation which modulates many subcarriers to be able to compensate for channel distortion as the characteristics of each phone line are rather different in the frequency domain. This same technology underlies many modern wireless protocols as well.
That might have been my misunderstanding. I had a (PhD) friend doing research for BT in the mid 90s in DSL technology (which hadn't been invented then, it was ISDN only) at Lancaster University UK, and he told me it was using shielding. Perhaps I've got it confused with a competing technology he was looking at at the time.
Yeah, I knew all that actually, but I guess I just associate dialup with the next generation of computers. Fundamentally I know it's a very similar tech to the tape-based game distribution, but for some reason it's categorized differently in my brain.
The PS1 used CDs. Many games could be dropped into a cd player, and if you skip the first track (the data track), the rest of the game's music/audio could be played.
It was possible to do the same with some PC games! I have fond memories of listening to the soundtracks of Driver, and Knights and Merchants, on my little stereo.
Cassette tapes for Atari 800XL used just a single channel for data. The other one could have music and you would listen to it during game loading.
Yeah, X-Wing vs Tie Fighter had a lot of the popular Star Wars music in redbook audio so it would work fine in a CD player, a fact that I was super excited to find out when I was a kid playing with my action figures.
Both the CD and the ZX Spectrum came out in 1982
If you had a CD playing device at home by 1982, it would be like having an 8K 60" TV today.
Or, as a better match, a high end VR device able to push 4k games to each eye at 120FPS.
Everyone and his grandma used tapes/cassetes until mid 90's.
Yeah, I was about to respond with something like this. I knew that CDs came out in the early 80's, but I still more or less associate them with the 90's; it wasn't expected that you bought a CD for music until then. As a very little kid I had cassettes for my sing-along tunes, by the time 6 or 7 (1997-1998), it feels like pretty much everyone had made the jump to CDs.
What I'm most curious about is if this was always just a happy side-effect of cassette-based data storage, or if they put specific effort into making this work. Ie. by being resilient to noise before and after a broadcast, having error correction, etc.
I'm curious how the timing worked - what happened if you were a few seconds early to record? Was the first part of the broadcast filled with noops?
ZX Spectrum tapes use a lead-in tone which the ROM code locks onto.
Random noise (and data! from a previous block) before that is ignored.
Zooming out, the format is:
Most software uses several of such blocks. Eg. a short BASIC loader, followed by a loading screen, followed by a # of KB's machine code.Lead-in (~4..5s usually), followed by a short header with program name & type of data that follows. A short pause. A shorter lead-in (~2s), followed by the data/program itself.As far as audio tape storage goes, the ZX Spectrum system was fairly reliable & user-friendly.
That's ignoring headerless blocks, speedloaders, and the many copy-protection schemes...
There was no error correction on ZX Spectrum, the protocol was very simple. IIRC a square wave with next bit encoded as timing of next edge, the last byte was XOR of the whole stream serving as error detection.
Technical details: https://sinclair.wiki.zxnet.co.uk/wiki/Spectrum_tape_interfa...
Assembly: https://worldofspectrum.net/legacy-info/spectrum-rom-load-ro...
TL;DR:
> A '0' bit is encoded as 2 pulses of 855 T-states each.
> A '1' bit is encoded as 2 pulses of 1710 T-states each (ie. twice the length of a '0')
> A 'pulse' here is either a mark or a space, so 2 pulses makes a complete square wave cycle.
Is this meant to confuse the aliens by suggesting we've decided to go back to 8 bits? (Love it, btw.)
Maybe :) Before "live to production" later tonight I tested it using a car FM transmitter adapter so things are already in motion haha.
Not just confuse them, but convince them we're not a threat, and thus not worth exterminating.
Don't broadcast PSSST! then. They may take it the wrong way.
I remember how proud of myself I was when I connected the computer's audio inputs to a standard casette player with speed up function so I could load the games twice as fast.
Out of curiosity, are there Linux tools to go from binary files to audio and back again? i.e `cat archive.zip | faxify -wav > archive.zip.wav`
Minimodem
Encode to opus:
Decode from opus:cat foo.zip | minimodem --tx -r 300 -f out.flac opusenc --bitrate 64 out.flac out.opusminimodem --rx -r 300 -f out.opus > foo2.zipfantastic, thanks!
FYI, there's a fun indie game from 2016 on all the major platforms called Lumo[1] that's an homage to the isometric puzzle/adventure games of the ZX Spectrum era. I didn't really know anything about said era, as it was mostly before my time, but I ended up looking up a bunch of stuff as I played and it gave me an appreciation for it. The director/developer has a full walkthrough with commentary on YouTube where he explains everything.[2]
[1] https://store.steampowered.com/app/345480/Lumo/
[2] https://www.youtube.com/playlist?list=PLHaRTzqB6QC9uzqnwNViw...
If I remeber correctly BBC also used to do this back in the day.
The BBC version was a small square of "static" broadcast in the corner of the closing credits of the Micro Show and you put and square plastic box (you could get from the show, I can't remember if you had to pay for them or not) with a light sensor over that "static" square and run the special software which take the data and save it as a file.
It wasn't terribly reliable but it was an interesting experiment by the BBC.
The "(BBC) Micro User" used to be published monthly, and had hardware project in each edition. Towards the end there were instructions on how to build your own acoustic-coupler modem where you pushed a regular telephone into two muffled cups. I think the only or main thing you could connect to was Prestel.
https://en.wikipedia.org/wiki/Prestel
It was a great machine for doing early robotics too - there was an Osbourne/Usbourne book on making an arm from balsa wood.
Prestel was my first online experience, over a 1200/75 baud modem (I just missed the acoustic coupler era, this was mid-80s) and led me onto dialing up many BBSs... much to my fathers gnashing of teeth when the quarterly British Telecom phone bill came through! Phone calls used to be expensive in the UK (even local).
I remember Micro User magazine, wish I still had my collection!
Does the BBC still have people in place doing experiments and R&D? I recall at one point they were researching/experimenting with audio codecs. I imagine this has taken a hit with funding cuts and general short-sightedness back home.
It is still very much a thing.
Also in East Germany, initiated by Prof. Horst Voelz (who was kind of a computer celebrity back then, basically the East German Konrad Zuse or Alan Turing).
Interestingly there was a cooperation with computer enthusiasts from the Netherlands which led to the adaption of the Dutch BASICODE standard in East Germany.
Also see (apologies for German link, but I guess machine translation will work well):
https://web.archive.org/web/20181107231024/http://r-h-voelz....
It's funny how we used to have games over radio waves (this, article, but 40 yars ago), then went through a bunch of other media (cartridges, floppies, cds, dvds, blurays,...) and then came back to games over radio waves (download via mobile network).
There was a game on Shakin' Stevens' album where you had to hide from bats and open green doors, and even the prawn cracker like snack Skips had a game, colin the biker. Mad times.
Was cassette tape storage more common in Europe than the U.S? I’m too young to have been around for this era, but I’ve just never seen it over here.
A tape drive was a standard accessory for the Commodore 64. Almost all games were on tape.
The Amstrad CPC 464 had a tape drive integrated into the chassis (the 6128 used a 3" floppy - not 3" 1/4, a 3" disk).
In the UK and Ireland, in the late 80s, the majority of games software in computer shops was for these two platforms (much cheaper than a PC), with a handful floppy disk stuff for PCs. Consoles came in from the toy shop side rather than the computer shop side.
My Mattel Aquarius had a tape drive.
The Apple II was the more dominant 8-bit micro in the US. My impression is that most owners got a disk drive. Probably because the Apple II’s disk drive was a marvel of engineering, being both cheap and fast. Meanwhile, the C64 had a drive that was very expensive and very slow, and hence most Commodore owners would just use the included cassette player.
Perhaps it was similar with the Spectrum?
It also makes some sense that users in the East Bloc would have trouble affording expensive hardware.
The spectrum didn't have an official (**) floppy disk add-on, the official mass storage upgrade* was the microdrive, which was a 100kB tape loop format - an improvement on cassettes, but not by much.
As a result, there was a wide range of unofficial floppy disk addons, which then brought the issue that there were so many competing products that supporting them all was near impossible and hardly any commercial software bothered.
Post main-popularity, most people settled on the Beta Disc / Beta 128 from Technology Research as being the main unofficial standard, somewhat bolstered by it being adopted in eastern europe and russia, but during the main popularity period, even it had really poor market share in the UK.
* There was also the cartridges for the Interface 2, but that's a different beast entirely and they were even less common than the Interface 1 + microdrive.
** of course there was the Spectrum +3 near the end of the spectrum's life which had a built-in 3" amstrad drive, which saw reasonable commercial support, but it was long after the main portion of the spectrum's popularity, and at a time when the ST and Amiga were beginning to dominate.
Interestingly enough, the plot of the game being broadcast was (if I remember correctly) about smuggling a new computer from the west. It was loaded with puns at the system (e.g. one of the locations was a government building and you had to navigate through its loopholes).
You've never had the pleasure of twiddling the volume control on a tape deck for the 15th time trying to get exactly the right setting for your game to not die two minutes into loading :(
It wasn't the volume, but the azimuth.
The azimuth adjustment screw :(
Back in the 80s, data storage on cassette was commonplace for 8-bit micros, because disk drives were expensive add-ons. I know I used them with my VIC-20 and TI-99/4A.
I had a TRS-80 Color Computer and struggled with a cassette tape interface that was faster than many competitors but wasn't reliable for me. The disc drive I added was more expensive than the computer but it was reliable and could support the OS/9 operating system
https://en.wikipedia.org/wiki/OS-9
which was better than the MS-DOS I used later on the much more powerful 286 machine that replaced my Coco 3.
As a silly test, I encoded the Spanish versions of the Sherlock Holmes' volumes (XZ compressed each one) to FLAC with minimodem --tx 300, and later I converted them to Opus at 64 Kbps.
Each file weighted less than 30MB, not bad at all. The raw WAV files were around 400MB each.
The files were re-read back with minimodem --rx at the same rate and dumped back to an XZ file, the sha512sum matched the originals.
With minimodem and some streaming service you can mimic that, but as a client you need to cache the data with mplayer or mpv to avoid losing data:
This is so cool! Does anyone know how the data is encoded in the signal? Is it just data for the game that's transmitted (and the logic resides on the ZX Spectrum) or is logic also transmitted?
The format is very simple, basically a square wave with different pulse widths for 1s and 0s [1]. Spectrum software was typically sold on audio cassettes and the radio broadcasts are the exact same format, typically people would record the broadcasts to cassette. The loader program in ROM just copies all the data from tape (or radio) into RAM so yes any game logic would be included in that.
It should be possible to capture using a sound card.
PCM recorder is probably easiest, and the most like a tape recorder as they're widely used as replacements for dictaphones.
Now could be the right time to put your old tape recorder on eBay (If you are in Slovenia) ;)
You can record it with a PC. Just make sure to use a lossless format
You can likely buy a new one on amazon for less than an old one on ebay.
This is AWESOME! But, I absolutely love this time period of computing history.
It was around this time (late 70s), before storage was accessible to computer nerds, that the Kansas City Standard was developed. It provided a cheap and easy way to store "large" amounts of data on standard audio cassettes which were cheap and easy to come by!
It really opened up a lot of things! People no longer needed to retype their programs in to the computer every time they turned it on, it was now easy to share & copy data with friends, and it ALSO gave us the ability to broadcast programs over the radio (like this article is doing!).
The original Kansas City Standard was pretty slow (300 baud), but other standards were developed shortly after (CUTS [Bob Marsh] is one) which provided more speed (1200 baud) and even backward compatibility with KCS.
If anyone is interested in a the dirty details of how KCS all works, I did a series on it (https://youtu.be/6m7vDhscGzU). And am working on covering CUTS in the near future!