Raspberry Pi Boots CP/M

Retrocomputing is an enjoyable and educational pursuit and — of course — there are a variety of emulators that can let you use and program a slew of old computers. However, there’s something attractive about avoiding booting a modern operating system and then emulating an older system on top of it. Part of it is just aesthetics, and of course the real retrocomputing happens on retro hardware. However, as a practical matter, retrocomptuters break, and with emulation, you’d assume that CPU cycles spent on the host operating system (and other programs running in the background) will take away from the target retrocomputer.

If you want to try booting a “bare metal” Z80 emulator with CP/M on a Raspberry Pi, you can try EMUZ80 RPI. The files reside on an SD card and the Pi directly boots it, avoiding any Linux OS (like Raspian). It’s available for the Raspberry Pi Model B, A+, and the Raspberry Pi 2 Model B. Unlike the significant boot times of the standard Linux distros on the earliest models of Pi, you can boot into CP/M in just five seconds. Just like the old days.

The secret to this development is an open source system known as Ultibo, a framework based on Open Pascal which allows you to create bare metal applications for the Raspberry Pi. The choice of Free Pascal will delight some and annoy others, depending on your predilections. Ultibo is still very much in active development, but the most common functions are already there; you can write to the framebuffer, read USB keyboards, and write to a serial port. That’s all you really need to make your own emulator or write your own Doom clone. You can see a video about Ultibo (the first of a series) below.

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Minimal Computer and Operating System: One Button, One LED

DUO BINARY is a very, very small computer system in every possible sense. It runs on an ATtiny84, which has even got “tiny” in its name. The user interface is a single button for data entry and a single LED for feedback, making this binary keyboard look frivolously over-complicated. It uses a devilish chimera of Morse code and a truncated ASCII to enter data, and the LED blinks the same back at you.

We’re guessing that [Jack Eisenmann] is the only person in the world who can control this thing, and you can watch him doing so in the video embedded below. Continue reading “Minimal Computer and Operating System: One Button, One LED”

Retro-Soviet Computer Brings The 80s Back

[Alex Zaikin] made a modern reproduction of an early-80s Soviet hobbyist home computer. Although the design was open, indeed it was published in “Radio” magazine, the project was a mammoth undertaking involving around 200 microchips, so not many “Mikro-80” computers were actually made.

[Alex] wanted to simplify the project and reduce the parts count. These days, 200 microchips’ worth of logic can easily fit inside an FPGA, and [Alex] wrangled the chip count down to seven. Moreover, he made it even easier to build your own retro minicomputer by building a modular platform: Retrobyte.

With the Retrobyte providing all of the essential infrastructure — SD card, tape recorder I/O, VGA outputs, and more — and the FPGA providing the brains, all that was left was to design a period keyboard and 3D print a nice enclosure. Project complete! Time for a few rounds of ASCII Tetris to celebrate.

We’ve covered a number of retro computer projects. We just have a soft spot for them, is all. If you don’t know what all the fuss is about, you could start out with a kit build to get your feet wet. Before long, you’ll be emulating ever obscurer computers of yore in custom logic. And when you do, be sure to drop us a line!

Differential Analyzer Cranks out Math like a Champ at VCF 2016

Here at VCF, we stumbled across a gigantic contraption that spanned several tables. Rube Goldberg machine this was not. Instead, this device actually does something useful! [Tim Robinson’s] differential analyzer can solve differential equations through several stages of mechanical integrators. The result is a pen-plot graph of the solution to the input equation, input by displacing a rod as a function of time.

Differential analyzers have been around for over a century. [Tim’s] claim to fame is that this particular DA is constructed entirely from Meccano-branded parts. We’re thrilled to see Meccano, over 100 years old at this point, continue to find new uses outside the toy box.

The Torque Amplifier

The differential analyzer is riddled with mechanisms that are bound to swing some heads for a double-take. Since the input shaft that transmits the input function f(x), has very little friction, the result can only be carried through the remainder of the machine with some means of torque amplification. To do so, [Tim], and most other DA designers implement a torque analyzer. For [Tim], though, this feat proved to be more difficult (and more triumphant) than other solutions, since he’s using a set of parts that are entirely from Meccano. In fact, this feature took [Tim] through about 20 iterations before he was finally satisfied.

VCF West continues to run through the end of the weekend at the Computer History Museum in Mountain View, CA. If you haven’t already packed your bags for DEF CON, stop by for a few more bewildering brain teasers.

Microcontrollers now substitute for CPUs

Microcontrollers are getting faster and faster, as is most of the rest of the computing world. Just like you can play Nintendo console games on the newest Nintendo handhelds, it seems that modern microcontrollers can replace CPUs on personal computers from the 80s. At least, that’s what [Dave] has shown with his latest project: an Atmel microcontroller that directly attaches to the CPU slot on a Commodore PET.

Essentially, the project started out as a test rig of sorts for the Commodore. [Dave] wanted to see if some of the hardware on the Commodore was still functional and behaving properly. From there, it somewhat snowballed. The address bus was easy enough to investigate, but adding only a few more pins on the microcontroller he was already using would be enough to access the databus too. A character table was soon added, a test algorithm, and more useful insights. It’s a masterful manipulation of this older hardware with modern technology and is definitely worth a look.

There’s a lot more going on in the retrocomputing world than meets the eye. One might think these old computers were all in landfills by now, but there is a devoted fanbase that does everything from building new hard drives for old computers or investigating their true audio-visual potential.

Thanks to [Mike w] for the tip!

Smallest BASIC Computer?

This may be the most minimal computer that we’ve ever seen running BASIC. Hackaday.io user [Kodera2t] has been working through the history of computing, so after his 4-bit CPU, he stepped up his game to eight bits. It’s amazing how much can be done with so little. It’s basically a Z80 on a single PCB.

[Kodera2t] is careful to give credit where credit is due: the design of this computer is by [Grant Searle]. It’s amazing what you can do with an old CPU (6809), some SRAM, a controller-interface chip, and an EPROM for your BASIC. Check out the GitHub for the computer’s PCB files if you want to make your own — it’s a very hobbyist-friendly two-layer board with fat traces. Or you could put it all together on a breadboard. It’s that non-critical.


The other sweet touch is this monochrome CRT build that pairs up with the tiny computer.

[Kodera2t] is doing some really clever retro and minimalistic hacks, and putting them all up on Hackaday.io. You should really give his whole portfolio a look. We recently wrote up his experimentations with the Atmel ATtiny10 if you’re in the mood for something more modern.

Restoring The Groundbreaking Xerox Alto

The Xerox Alto was a minicomputer that had a lot of firsts to its name: first GUI, first Ethernet connection, and first computer to use a laser printer. This is the computer that inspired Steve Jobs to build the Lisa. And this was built all back in 1973! So when [Ken Shirriff] and a team of other old-computer aficionados got their hands on one, you know they’d get to work.

[Ken]’s blog describes the start of what’s sure to be a long journey. It mostly describes the Alto system and locates its place in computer history, but there are some interesting sidelines as well — like how [Alan Kay] also basically outlined all of the functionality of the modern laptop / tablet along the way to the Alto; it was supposed to be an interim Dynabook.

Work on this grandfather-of-modern-computers is just getting started, and [Ken] and crew are dusting off the power supplies and cataloguing memory boards. You can be sure that we’ll follow along with this restoration project, and keep you informed.