Secret C64 Program Found On A Christian Rock Band’s Vinyl Record

How often do you find Easter eggs in old vinyl records?

It sure was a surprise for [Robin Harbron] when he learned about a Commodore 64 program hidden on one of the sides of a record from the 1985 album of Christian rock band Prodigal. The host of the YouTube channel 8-Bit Show and Tell shows the “C-64” etching on one side of the vinyl, which he picked up after finding out online that the record contained the hidden program.

The run-out groove on records is typically an endless groove that keeps the record player from running off the record (unless there is an auto-return feature, which just replays the record). On side one of the vinyl, the run-out groove looks normal, but on side two, it’s a little thicker and contains some hidden audio. Recording the audio onto a cassette and loading it onto a dataset reveals a short C64 program.

The process is a little more troublesome that that, but after a few tries [Harbron] reveals a secret message, courtesy of Albert Einstein and Jesus Christ. It’s not the most impressive program ever written, but it’s pretty cool that programmers 35 years ago were able to fit it into only a few seconds of audio.

Unfortunately, we won’t be hearing much actual music from the album – [Harbron] chose not to play the songs to avoid copyright issues on YouTube.

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This Handheld C64 Design Study Needs To Be Made

The Commodore 64 remains the best selling home computer of all time, and is unlikely to be toppled anytime soon. It continues to inspire a diehard community of makers and hackers to this day. [Cem Tezcan] is one of those people, and his design study of a handheld C64 is utterly droolworthy.

It’s quite likely that you’d run out of power before the cassette finished loading, but hey, we can dream.

The study includes renders of the device from several angles, as well as a basic blueprint outlining the various components. It features period accurate hardware, using a membrane keyboard, micro-cassettes for data storage, and a 3.5″ CRT. Other nice touches are the big red textured FIRE button, and a horrible early 80s 3.5mm jack.

The C64 hardware of the time required both 12 V and 5V power, and the current draw of even a small CRT would be high. It’s likely such a handheld would have battery life measured in minutes. It’s a wonderful picture of what could have been, though we suspect that such a design would have pushed the limits of the technology of the time.

However, electronics has matured since, and we sit here rather comfortably in 2019. We’d love to see the best handheld C64 that the community can muster, and with 3D printers and FPGAs on hand, it’s an eminently achievable feat. Bonus points to anyone who can make a microdatasette interface, too. All submissions to the tips line, and meanwhile, consider how easy it is to build a new C64 from scratch. Happy hacking!

How A Secret Gaming Scene Emerged In Communist East Germany

During the late 1980s, a gaming scene emerged in East Germany just before the fall of communism. Teenagers gathered in buildings like the “House of Young Talents” (HdjT), originally Palais Podewils, to watch and play Commodore 64 games. There were 20 similar clubs in Berlin alone, sometimes with more than 70 people crowded into a single room. Above all, the computers they were in possession of were all made in the West.

At a point in time when loyalties were frequently questioned, the club of self-proclaimed “freaks” soon attracted the attention of the Stasi, GDR (East Germany) intelligence agents who kept close tabs on the group. As one Stasi agent warned:

Given that there are also members within the interest groups or computer clubs with a verifiably negative attitude toward the socialist state and social order, there is a potential danger that the interest groups or computer clubs will go in a negative direction.

Domestically produced computers – the KC 85 from VEB Mikroelektronik Wilhelm Pieck Mühlhausen and the KC 87 from VEB Robotron – did not have the quality of C128 and C64s from Commodore. Surprisingly, even while microelectronics remained on the list of embargoed products imported to East Germany, C64s managed to make their way into the state. The GDR customs officials didn’t have any problem with Western imported hardware – what they were worried about was the software.

By the end of the 80s, modern data traffic over telephone lines had arrived in East Germany, causing fear that software would soon be disseminated without the need of a physical medium. For the gamers of GDR, however, many didn’t even have access to a phone line. They just wanted to go to computer clubs to swap software. Since computer games from the West were only available in government-run Intershop stores and not in normal shops, teenagers had to rely on the computer clubs to access these games. Games like Frogger and Rambo would be copied to cheaper cassette tapes – it wouldn’t even be violating the saw law since software was not protected by copyright within the country.

A few politically charged games – “Raid Over Moscow” and “Kremlin” – were forbidden to ensure that the HdjT wouldn’t be shut down. Towards the end of the GDR, the Stasi desperately tried to gain control of games “relating to the increasing activities of the political opponent”, but by this point the political situation was already heading towards the fall of the Wall. [Stefan Paubel], founder of the HdjT reflected that he was disappointed the Stasi didn’t try harder to report on the computer clubs.

They had everything critical in the reports: Swapping software, a complete list of all the games glorifying war and computers from the West.

It appeared that microelectronics were sacred to the GDR, since officials were trying to get more young people to engage with computers. The regime’s concern for their reputation led them to prioritize other forms of surveillance than technology. For a while after the fall of the Berlin Wall, the computer club continued to exist. It wasn’t until August 1990, two months before reunification, that the remaining members decided to dissolve the club.

[Thanks to Frank for the tip!]

How Many Commodores Does It Take To Crack A Nut?

It’s brilliant enough when composers make use of the “2SID” technique to double the channels in a Commodore 64 with two sound chips, but even then some people like to kick things up a notch. Say, five times more. [David Youd], [David Knapp] and [Joeri van Haren] worked together to bring us just that, ten Commodore computers synchronously playing a beautiful rendition of the Dance of the Sugar Plum Fairy at this year’s Commodore Retro eXpo.

The feat is composed of nine Commodore 64 computers and one Commodore 128, all fitted with the SID chip. It is a notorious synthesizer chip for utilizing both analog and digital circuitry, making each and every one of its revisions unique to a trained ear, not to mention impossible to faithfully reproduce in emulation. The SID was designed by Bob Yannes at MOS Technology, who later went on to co-found Ensoniq with his experience in making digital synthesizers.

How this orchestra of retro computers came to be, including details on how everything is pieced together can be found on this slideshow prepared by the authors of the exhibition. It’s interesting to note that because of timing differences in each computer’s crystal clock and how only the start of the song is synchronized between them, they can’t play long music tracks accurately yet, but a 90-second piece works just fine for this demonstration.

These synthesizer chips are slowly going extinct since they’re no longer being manufactured, so if you need a new replacement solution, FPGAs can fill that SID-shaped hole in your heart. If you need the whole computer though, the newer Teensy 3.6 will do just fine emulating it all. Check out this beast of a display in action after the break. While we’re at it, this isn’t the only time multiple 8-bit computers have been combined as an orchestra, though these Commodores sound a lot better than a table full of ZX Spectrums.

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Dirty Tricks For 6502 Programming

We know the 6502 isn’t exactly the CPU of choice for today’s high-performance software, but with the little CPU having appeared in so many classic computers — the Apple, the KIM-1, The Commodores, to name a few — we have a real soft spot for it. [Janne] has a post detailing the eight best entries in the Commodore 64 coding competition. The goal was to draw an X on the screen using the smallest program possible. [Janne] got 56 bytes, but two entrants clocked in at 34 bytes.

In addition to the results, [Janne] also exposes the tricks people used to get these tiny programs done. Just looking at the solution in C and then 6502 assembly is instructive. Naturally, one trick is to use the existing ROM code to do tasks such as clearing the screen. But that’s just the starting point.

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The Benefits Of Restoring A C64 With A Modern FPGA Board

The Commodore 64 was the highest selling computer of all time, and will likely forever remain that way due to the fragmentation of models in the market ever since. Due to this, it’s hardly surprising that it still has a strong following many years after its heyday. This means that the avid restorer has a wide range of parts and support available at the click of a button. [DusteD] is just one such person who had a busted-up C64 laying around, and decided to make it a project.

[DusteD] wanted to reuse the original case, and decided it should remain a Commodore 64 after an initial attempt at a mini-ITX swap went awry. Desiring a reliable machine, an Ultimate64 FPGA board was selected to replace the original faulty motherboard. This has the benefit of being hardware compatible with the classic C64, while allowing [DusteD] to tinker and program to his heart’s content, without having to worry about blowing up valuable original parts. It also provides several interesting modern features, like HDMI output, USB, and even Ethernet connectivity. This allows one to experiment with the platform without the hassles of all the inherent limitations of 1980s technology.

As a fan of the classic SID sound chip, [DusteD] was also highly interested in the audio output of the Ultimate64. Recordings were made of the emulated output from the FPGA, as well as the sound output from a real SID installed in the board, both through the mixed output and directly from the chip via a SIDTAP. Those interested can download the 800MB of recordings and compare the output; there’s a summary of the differences noted listed on the site as well.

[DusteD] makes a great argument for the benefits of building up a C64 rig in this way. It’s a great way to get started for those eager to explore the world of Commodore’s 8-bit hardware without the hassles and expenses of buying all the real gear. As it stands, the C64 aftermarket is so advanced now, that you can build an entirely new machine from scratch if you so desire. Go forth and enjoy!

Recovering Data From Floppies With Errors

Those of us of advancing years will remember the era of the floppy disc. Maybe not that of the 8-inch drive, but probably its 5.25-inch and certainly its 3.5-inch cousins. Some will remember the floppy disc fondly, while for others there will be recollections of slow and unreliable media with inadequate capacity, whose ability to hold data for any length of time was severely questionable. Add three decades to the time a disc has spent in storage, and those data errors become frequent. The life of a retrocomputing enthusiast hoping to preserve aged software is made extremely difficult by them, and [] has a few tips to help with recovery.

It’s written with specific reference to Commodore 5.25-inch floppies, but aside from some of the specific software, the techniques could be applied to any discs. Most interesting is his explanation of the mechanisms that lead to bad discs or bad sectors, before he looks at some of the mitigations that might be employed. Cleaning the disc or the drive head with alcohol is explored, then taking a dump of the raw data for detailed inspection and disassembly in search of checksum errors. If in your youth a floppy disc was just something you put in a drive and you never investigated further, perhaps this piece will fill in some of the gaps.

If the thought of a stack of Commodore 64 floppies fills you with dread, how about using an emulator?

Header image: PrixeH [CC BY-SA 3.0].