Trying (and Failing) To Restore A 1970s CDC 10MB Hard Drive

February 28, 2023 by 33 Comments

One fun aspect of 1970s-era hard disk drives is that they are big, clunky and are fairly easy to repair without the need for a clean room. A less fun aspect is that they are 1970s-era HDDs and thus old and often broken. While repairing a CDC 10 MB HDD for the upcoming VCF East event, the folks over at [Usagi Electric], this led to quite a few struggles, even after a replacement 14″ platter was found to replace the crashed platter with.

These CDC HDDs are referred to as Hawk drives, and they make the associated 8-bit Centurion  TTL logic-based computers so much faster and easier to work with (for a 1970s system, of course). Despite the large size of the components involved and the simple, all through-hole nature of the PCBs, issues that cropped up ranged from corroded DIP switches, to head alignment sensors, a defective analog board and ultimately a reported bad read-write head.

Frustratingly, even after getting the platters to spin up and everything moving as intended, it would seem that the remaining problem is that of possibly bad read-write heads, as in plural. Whether it’s due to age, previous head crashes onto platters, or something else, assembling a working Hawk drive turned out to be somewhat more complicated than hoped.

We definitely hope that the bunnies can get a working Hawk together, as working 1970s HDDs like these are become pretty rare.

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Hackaday Podcast 207: Modular Furniture, Plastic Prosthetics, And Your Data On YouTube

February 24, 2023 by 6 Comments

Join Editor-in-Chief Elliot Williams and Managing Editor Tom Nardi as they explore the best and most interesting stories from the last week. The top story if of course the possibility that at least some of the unidentified flying objects the US Air Force valiantly shot down were in fact the work of amateur radio enthusiasts, but a quantitative comparison of NASA’s SLS mega-rocket to that of popular breakfast cereals is certainly worth a mention as well.

Afterwards the discussion will range from modular home furnishings to the possibility of using YouTube (or maybe VHS tapes) to backup your data and AI-generated Pong. Also up for debate are cheap CO2 monitors which may or may not be CO2 monitors, prosthetic limbs made from locally recycled plastic, and an answer to Jenny’s Linux audio challenge from earlier this month.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Screenshot of KiCad 7 feature that lets you overlay a PCB bitmap image and draw traces over it, being used for board reverse-engineering purposes

KiCad 7.0.0 Is Here, Brings Trove Of Improvements

February 13, 2023 by 109 Comments

Yesterday, the KiCad team has released KiCad 7.0.0 – a surprise for those of us who have only gotten used to the wonders of KiCad 6, and it’s undoubtedly a welcome one! Some of these features, you might’ve seen mentioned in the KiCad 2022 end-of-year recap, and now, we get to play with them in a more stable configuration. There’s a trove of features and fixes for all levels of KiCad users, beginners, hobbyists and professionals alike – let’s start with some that everyone can appreciate! Continue reading “KiCad 7.0.0 Is Here, Brings Trove Of Improvements” →

Surfing The Web Like It’s 1978 — Carbonyl

February 6, 2023 by 29 Comments

[Fathy] gets a kick out of doing odd things with Chromium, and Carbonyl is a clever byproduct of that hobby. In this case, it’s what you get when you connect chrome’s renderer to an SVG output module and then convert that SVG to colored characters on a terminal. See, html2svg is an earlier project, taking Chromium’s Skia engine and plugging it into an SVG back-end. And once you have SVG, why not render it to the terminal?


And the results are actually pretty impressive. Imagery is rendered using Unicode 2584, a half-block character. The background and foreground color can be set per character, giving us two controllable pixels per character. Text is handled a bit differently, rendering using the normal text fonts, making for readable pages.

The source is very much a work in progress, but there are some neat ideas already coalescing around the project, like using sixels for better rendering. There’s already decent mouse support and audio output, making for an impressive terminal experience. This might be a project to keep an eye on.

A visually accurate replica of the MCM/70 computer, an all in one system with a keyboard, dual cassette drives and a small one line display

MCM/70 Replica Embodies Proud Canadian Heritage

February 4, 2023 by 17 Comments

When a vintage computer is all but unobtanium, software emulation is often all that remains. Unless you are [Michael Gardi], who saw an opportunity to reproduce Canada’s home-grown MCM/70 microcomputer using a combination of software emulation and modern hardware.

Short of building a brand new MCM/70 from the original schematics, this faithful facsimile of the MCM/70 does everything it can to pay homage to the original machine. The foundations of this project can be attributed to the York University Computer Museum (YUCoM) MCM/70E emulator, highly regarded for its “historical accuracy”. The MCM/70 used dual cassette tapes for storage and a funky 32-character dot matrix plasma display, which is all reproduced in software (other versions dropped one of the cassette drives for a modem, bleeding edge innovation for 1974 microcomputing).

From here, [Michael] set off to assemble the various physical components of the original computer. The chassis itself was built from scratch using a mixture of 3D printing and traditional woodwork. The high-voltage plasma display was recreated using four HCMS-2972 dot matrix modules, which minor compromises. The original computer used display memory as extra storage when executing instructions, which created a sporadic blinkenlights effect on the original display. This new display unfortunately won’t reproduce this ‘thinking’ pattern, but it’s a small sacrifice.

Similarly, the original keyboard was going to be challenging to replicate with 100% accuracy, so a brand-new recreation of an Ohio Scientific computer keyboard was used instead. The layouts are extremely similar, and anyone except your most committed Canadian retro computing enthusiasts probably wouldn’t notice the difference. Being a modern recreation of a vintage keyboard, this was relatively easy to source. A set of custom-made keycaps with APL legends really helped sell the replica.

And while working dual cassette drives would have brought this project home, it’s commendable that [Michael] has created ‘working’ cassette drives using 3D printed cassettes and some magnetic magic using hall effect sensors to identify the loaded cassette. The emulator incorporates three virtual cassette tapes which made this solution possible.

If this all sounds familiar, it might be because this project was based on a superb Hackaday writeup of the MCM/70. A truly innovative computer for its time, the story behind Micro Computer Machines (not to be confused with the toy cars) is a fascinating tale, and the write-up is worth a read if you haven’t seen it already.

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Showing two MCP23017 expanders soldered onto a PCB

MCP23017 Went Through Shortage Hell, Lost Two Inputs

February 3, 2023 by 68 Comments

The MCP23017, a 16-bit I2C GPIO expander, has always been a tasty chip. With 16 GPIOs addressable over I2C, proper push/pull outputs, software-enabled pull-ups, eight addresses, maskable interrupts for all pins, and reasonably low price, there’s a reason it’s so popular. No doubt due in part to that popularity, it’s been consistently out of stock during the past year and a half, as those of us unlucky enough to rely on it in our projects will testify.

Now, the chip is back in stock, with 23,000 of them to go around on Mouser alone, but there’s a catch. Apparently, the lengthy out-of-stock period has taken a heavy toll on the IC. Whether it’s the recession or perhaps the gas shortages, the gist is — the MCP23017 now a 14/16-bit expander, with two of the pins (GPA7 and GPB7) losing their input capabilities. The chips look the same, are called the same, and act mostly the same — if you don’t download the latest version of the datasheet (Revision D), you’d never know that there’s been a change. This kind of update is bound to cause a special kind of a debugging evening for a hobbyist, and makes the chip way less suitable for quite a few applications.

It’s baffling to think about such a change happening nearly 20 years after the chip was initially released, and we wonder what could have caused it. This applies to the I2C version specifically — the SPI counterpart, MCP23S17, stays unaffected. Perhaps, using a microcontroller or shift registers for your GPIO expansion isn’t as unattractive of an option after all. Microcontroller GPIO errata are at least expected to happen, and shift registers seem to have stayed the same since the dawn of time.

The reasons for MCP23017 silicon getting cut in such a way, we might never know. At least now, hopefully, this change will be less of a bitter surprise to those of us happy to just see the chip back in stock — and for hackers who have already restocked their MCP23017 hoards, may your shelved boards magically turn out to have a compatible pinout.

Retrotechtacular: Critical Code Reading, 70s Style

January 5, 2023 by 30 Comments

Anyone who has ever made a living writing code has probably had some version of the following drilled into their head: “Always write your code so the next person can understand it.” Every single coder has then gone on to do exactly the opposite, using cryptic variables and bizarre structures that nobody else could possibly follow. And every single coder has also forgotten the next part of that saying — “Because the next person could be you” — and gone on to curse out an often anonymous predecessor when equally inscrutable code is thrust upon them to maintain. Cognitive dissonance be damned!

It’s a tale as old as time, or at least as old as programming has existed as a profession. And by 1975, poorly written code was enough of a problem that an outfit called Edutronics put together the animated gem Critical Program Reading: Structuring an Unstructured Program. It’s apparently Part 1 of a larger series on structured programming techniques, and comes to us by way of [Alec Watson], host of Technology Connections on YouTube, by way of his second channel, the delightfully named Technology Connextras.

The film’s three minimally animated characters, each of whom could have been the villain in an episode of Scooby Doo, are tasked by a stern-sounding narrator to analyze a fragment of pseudocode that’s written in a concoction of COBOL, PL/1, and a bunch of other languages. The code is a hot mess, but our heroes muddle through it line by awful line, making it more readable by guessing at more descriptive variable names, adding structured elements, and making logical changes to improve the program’s flow. The example code is highly contrived, to be sure, but the business logic becomes much clearer as our team refactors the code and makes it far more approachable.

For as much as languages have changed since the 1970s, and with all the progress we’ve made in software engineering, the lessons presented in this film are still surprisingly relevant. We loved a lot of the little nuggets dropped along the way, like “Consistency aids understanding,” and “Use symbols in a natural way.” But we will take exception with the statement “Wrong means poor structure” — we’ve written seen plenty of properly structured code that didn’t work worth a damn. We also enjoyed the attempt at socially engineering a less toxic work environment: “Use tact in personal criticisms.” If only they could learn that lesson over at Stack Overflow.

It’s not clear where [Alec] found this 16-mm film — we’d sure like to hear that story — but it’s a beauty and we’re glad he took the time to digitize it. We’re consistently amazed at his ability to make even the most mundane aspects of technology endlessly fascinating, and while this film may be a bit off from his normal fare, it’s still a great find. Continue reading “Retrotechtacular: Critical Code Reading, 70s Style” →