Retrocomputing

1400 Articles

Piers holding a USB One ROM.

One ROM Gets A USB Stack

October 9, 2025 by 3 Comments

Our hacker [Piers Finlayson] is at it again, and this time he has added USB support to One ROM.

With this new connectivity you can attach your One ROM to your computer with a USB cable and then in a matter of seconds upload new firmware from your Chrome (or Chromium) web browser. This new connectivity will supplement but not replace the existing serial wire connectivity because the serial wire connectivity enables certain advanced use cases not supported by the USB stack, such as reprogramming a ROM in-place as it’s being served. The new USB interface will probably suit most users who just want to use One ROM to manage the ROMs for their old kit and who don’t need the extra functionality.

Addressing the question as to why he didn’t have USB connectivity from the start [Piers] claimed it was because he didn’t like soldering the USB sockets! But given this is a service he can get from his board house that is no longer his problem! [Piers] said he picked Micro USB over USB-C because the former demands less circuit board real estate than the latter. Squeezing everything on to the board remains a challenge!

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A Minicomputer Tape Drive Receives Some Love

October 8, 2025 by 6 Comments

Taking on a refrigerator-sized minicomputer  is not for the faint-hearted, but [Usagi Electric] has done it with a DEC PDP-11/44. He’s not doing it in half measures either, for his machine is tricked out with an impressive array of upgrades. Among them however is no storage, and with two co-processors there’s a meager 3U of rack space left. The plan is to fit a period 8″ hard drive in the space alongside a TU50 tape dive, and it’s this final component that’s the subject of his latest video.

DEC never did anything by halves, and a DECTape II cartridge is more than a simple container for tape reels. Instead it has a capstan of its own that engages with one in the drive, and an internal drive belt that moves the reels. All the rubber parts in both tapes and drive are thoroughly perished, and it’s impressive that he manages to find inexpensive modern polymer alternatives. The original drive is probably intended for a VAX system, thus it has the interesting feature of a second drive mechanism out of sight to hold a tape containing microcode.

Having reconditioned the drive, it goes in behind a custom front panel, and though there’s no useful data to test it with on the tapes he has, it appears all working. You can see it all in the video below the break, and if you’re interested further we’ve covered this machine in the past.

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A Lorenz Teletype Shows Us Its Secrets

October 7, 2025 by 23 Comments

When we use the command line on Linux, we often refer to it as a terminal. It’s a word with a past invoking images of serial terminals, rows of green-screened machines hooked up to a central computer somewhere. Those in turn were electronic versions of mechanical teletypes, and it’s one of these machines we’re bringing you today. [DipDoT] has a Lorenz teletype from the 1950s, and he’s taking us through servicing and cleaning it, eventually showing us its inner workings.

The machine in question had been in storage for many years, but remained in good condition. To be this long out of use though meant it needed a thorough clean, so he sets about oiling the many hundreds of maintenance points listed in a Lorenz manual. It’s a pleasant surprise for us to see keyboard and printer unit come away from the chassis for servicing so easily, and by stepping it through its operation step by step we can see how it works in detail. It even incorporates an identifier key — think of it as a mechanical ROM that stores a sequence of letters — which leads him to believe it may have come from a New York news office. The video is below the break, and makes for an interesting watch.

He’s going to use it with a relay computer, but if you don’t have one of those there are more modern ways to do it.

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How Your SID May Not Be As Tuneful As You’d Like

October 4, 2025 by 6 Comments

The MOS Technologies 6581, or SID, is perhaps the integrated circuit whose sound is most sought-after in the chiptune world. Its three voices and mix of waveforms define so much of our collective memories of 1980s computing culture, so it’s no surprise that modern musicians seek out SID synthesisers of their own. One of these is the MIDISID, produced by [MIDI IN],  and in a recent video she investigates an unexpected tuning problem.

It started when she received customer reports of SIDs that were out of tune, and in the video she delves deeply into the subject. The original SID gained its timing from a clock signal provided by the Commodore 64, with thus different timing between NTSC and PAL versions of the machine. This meant European SID music needed different software values to American compositions, and along the way she reveals a localisation error in that the British Commodore 64 manual had the wrong table of values.

Modern SIDs are emulated unless you happen to have an original, and her problem came when switching from one emulated SID to another. The first one used that clock pin while the second has its own clock, resulting in some music being off-tune. It’s a straightforward firmware fix for her, but an interesting dive into how these chips worked for the rest of us.

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A Treasure Trove Of Random Vintage Tech Resources

October 3, 2025 by 7 Comments

Finding, collecting, and restoring vintage tech is the rewarding pastime of many a Hackaday reader. Working with old-school gear can be tough, though, when documentation or supporting resources are hard to find. If you’re in need of an old manual or a little scrap of software, you might find the Vintage Technology Digital Archive (VTDA) a useful destination.

The VTDA is a simple website. There is no search function, or fancy graphical way to browse the resources on offer. Instead, it’s merely a collection of files in a well-ordered directory tree. Click through /pics/DiskSleeves/VTDA/ and you’ll find a collection of high-resolution scans of various old diskettes and their packaging. /docs/computing/Centronics/ will give you all kinds of useful documentation, from press releases to datasheets for printers long forgotten. You can even find Heathkit schematics and old Windows bootdisk images if you dive into the depths.

While it doesn’t have everything, by any means, the VTDA has lots of interesting little bits and pieces that you might not find anywhere else. It’s a great counterpart to other archival efforts out on the web, particularly if you’re a member of the retrocomputing massive.

Thanks to [Itay] for the tip!

Lost Techniques: Bond-out CPUs And In Circuit Emulation

October 1, 2025 by 18 Comments

These days, we take it for granted that you can connect a cheap piece of hardware to a microcontroller and have an amazing debugging experience. Stop the program. Examine memory and registers. You can see and usually change anything. There are only a handful of ways this is done on modern CPUs, and they all vary only by detail. But this wasn’t always the case. Getting that kind of view to an actual running system was an expensive proposition.

Today, you typically have some serial interface, often JTAG, and enough hardware in the IC to communicate with a host computer to reveal and change internal state, set breakpoints, and the rest. But that wasn’t always easy. In the bad old days, transistors were large and die were small. You couldn’t afford to add little debugging pins to each processor you produced.

This led to some very interesting workarounds. Of course, you could always run simulators on a larger computer. But that might not work in real time, and almost certainly didn’t have all the external things you wanted to connect to, unless you also simulated them. Continue reading “Lost Techniques: Bond-out CPUs And In Circuit Emulation” →

YouTube… Over Dial Up

September 29, 2025 by 25 Comments

In the days of yore, computers would scream strange sounds as they spoke with each other over phone lines. Of course, this is dial up, the predecessor to modern internet technology, offering laughable speeds compared to modern connections. But what if dial up had more to offer? Perhaps it could even stream a YouTube video. That’s what the folks over at The Serial Port set out to find out.

The key to YouTube over dial up is a little known part of the protocol added right around the time broadband was taking off called multilink PPP. This protocol allows for multiple modems connected to a PC in parallel for faster connections. With no theoretical limit in sight, and YouTube’s lowest quality requiring a mere 175 Kbps, the goal was clear: find if there is a limit to multilink PPP and watch YouTube over dialup in the process.

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