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.

New Hard Drives for Old Computers

After a certain age, computers start to show signs that they might need to be replaced or upgraded. After even more time, it starts getting hard to find parts to replace the failing components. And, as the sands slip through the hourglass, the standards used to design and build the computer start going obsolete. That’s the situation that [Drygol] found himself in when he was asked to build a SD-card hard drive for an Atari.

The 8-bit Atari in question was a fixture of home computing in the 80s. In fact, if you weren’t on the Commodore train, it’s likely that your computer of choice was an Atari. For the nostalgic among us, a new hard drive for these pieces of history is a great way to relive some of the past. Working off of information from the SIO2SD Wiki page, [Drygol] used the toner transfer method to build a PCB, 3D printed a case, and got to work on his decades-old computer.

Resurrecting old hardware is a great way to get into retrocomputing. Old protocols and standards are worth investigating because they’re from a time where programmers had to make every bit count, and there are some gems of genius hidden everywhere. Whether you’re reworking SIO from an old Atari, or building a disk emulator for an Apple ][, there are lots of options.

Walnut Windfall Winds up in Custom Keyboard

When a neighbor decided to cut down a walnut tree, [voluhar] decided to make something of the wood. The result was this custom keyboard that combines wood and metal in a lovely and functional package.

Walnut is a wood with a rich heritage in consumer electronics. Back in the early days of TV, huge console sets were built into solid walnut cabinets and proudly displayed along with the other fine furnishings in a home. [voluhar]’s keyboard captures a little of that spirit while retaining all the functionality you’d expect. From the custom PCB to the engraved aluminum key caps, it looks like every part was machined with a CNC router. The keyboard sports satisfyingly clicky Cherry MX switches, and a few cleverly positioned LEDs provide subtle feedback on the state of the locking keys. As for the imperfections in the walnut case, we think it just adds to the charm and warmth of the finished product, which would look great on any desktop.

Wood has appeared in a couple of custom keyboards that we’ve featured before, like this all-wood version. But if you want the retro look without the wood, you could always try a keyboard built out of a typewriter.

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1000 CPUs on a Chip

Often, CPUs that work together operate on SIMD (Single Instruction Multiple Data) or MISD (Multiple Instruction Single Data), part of Flynn’s taxonomy. For example, your video card probably has the ability to apply a single operation (an instruction) to lots of pixels simultaneously (multiple data). Researchers at the University of California–Davis recently constructed a single chip with 1,000 independently programmable processors onboard. The device is energy efficient and can compute up to 1.78 trillion instructions per second.

The KiloCore chip (not to be confused with the 2006 Rapport chip of the same name) has 621 million transistors and uses special techniques to be energy efficient, an important design feature when dealing with so many CPUs. Each processor operates at 1.78 GHz or less and can shut itself down when not needed. The team reports that even when computing 115 billion instructions per second, the device only consumes about 700 milliwatts.

Unlike some multicore designs that use a shared memory area to communicate between processors, the KiloCore allows processors to directly communicate. If you are just a diehard Arduino user, maybe you could scale up this design. Or, if you want to make use of the unused power in your video card under Linux, you can always try to bring KGPU up to date.

Make Math Real with this Analog Multiplier Primer

Remember learning all about functions in algebra? Neither do we. Oh sure, most of us remember linear plots and the magic of understanding y=mx+b for the first time. But a lot of us managed to slide by with only a tenuous grasp of more complex functions like exponentials and conic sections. Luckily the functionally challenged among us can bolster their understanding with this demonstration using analog multipliers and op amps.

[devttys0]’s video tutorial is a great primer on analog multipliers and their many uses. Starting with a simple example that multiplies two input voltages together, he goes on to show circuits that output both the square and the cube of an input voltage. Seeing the output waveform of the cube of a ramped input voltage was what nailed the concept for us and transported us back to those seemingly wasted hours in algebra class many years ago. Further refinements by the addition of an op amp yield a circuit that outputs the square root of an input voltage, and eventually lead to a voltage controlled resistor that can attenuate an input signal depending on its voltage. Pretty powerful stuff for just a few chips.

The chip behind [devttys0]’s primer is the Analog Devices AD633, a pretty handy chip to have around. For more on this chip, check out [Bil Herd]’s post on analog computing.

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Designing A Single Instruction Computer

Today’s computers are unimaginably complex, and so complicated it’s nearly impossible for anyone to comprehend everything a CPU can do in excruciating detail. It wasn’t always like this – the early CPUs of the 70s and 80s were relatively simple and can easily be recreated at the individual gate level. CPUs can be even simpler, as [Jack Eisenmann] demonstrates with a single instruction computer, the DUO Compact 2, made entirely out of 74-series logic chips and a bunch of memory.

[Jack] has a long history of building strange computers out of individual chips, including a TTL logic CPU and a significantly more complicated single instruction computer. The latest, though, is as simple as it gets. It’s just twenty chips, capable of calculating prime numbers, sorting strings, and everything else a computer is able to do.

With every one-instruction computer, there is the obvious question of what instruction this computer uses. For the DUO Compact 2 it’s a single instruction that accepts three arguments, A, B, and C. The instruction copies a byte from A to B, then jumps to the instruction at C. Is it even possible for a computer to add two numbers with this instruction? Yes, if you have massive look up tables stored in 2 Megabytes of Flash and 512 kB of RAM.

In the video below, [Jack] goes over how his tiny computer works and demonstrates prime number generation (it’s slow), string sorting (also slow), and displaying ’99 bottles of beer on the wall’ on the computer’s LCD. All the files to replicate this computer are available on [Jack]’s webpage, along with an emulator in case you don’t want to break out a breadboard for this one.

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The Raspberry Pi Infinity+ Is A Fully Functional Huge Raspberry Pi

It wasn’t an easy weekend for the rest of the world’s hackers and makers, that of the Bay Area Maker Faire. Open your social media accounts, and most of your acquaintances seemed to be there and having a great time, while the rest were doing the same at the Dayton Hamvention. Dreary televised sports just didn’t make up for it.

MCM Electronics had the Maker Faire booth next to that of the Raspberry Pi Foundation, and since they needed both a project to show off and a statement item to draw in the crowds, they came up with the idea of a 10x scale reproduction of a Raspberry Pi above the booth. And since it was Maker Faire this was no mere model; instead it was a fully functional Raspberry Pi with working LEDs and GPIO pins.

The project started with a nearly faithful (We see no Wi-Fi antenna!) reproduction of a Raspberry Pi 3 in Adobe Illustrator. The circuit board was a piece of MDF with a layer of foam board on top of it with paths milled out for wiring and the real Pi which would power the model, hidden under the fake processor. The LEDs were wired into place, then the Illustrator graphics were printed into vinyl which was wrapped onto the board, leaving a very two-dimensional Pi.

The integrated circuits and connectors except for the GPIO pins were made using clever joinery with more foam board, then wrapped in more printed vinyl and attached to the PCB. A Pi camera was concealed above the Broadcom logo on the processor model, to take timelapse pictures of the event. This left one more component to complete, the GPIO pins which had to be functional and connected to the pins on the real Pi concealed in the model. These were made from aluminium rods, which were connected to a bundle of wires with some soldering trickery, before being wired to the Pi via the screw terminals on a Pi EZ-Connect HAT from Alchemy Power.

Is the challenge now on for a range of compatible super-HATs to mate with this new GPIO connector standard?

We previously covered the 2012 Maker Faire exhibit that inspired this huge Pi. The Arduino Grande was as you might well guess, a huge (6x scale) fully functional Arduino. In fact, the world seems rather short of working huge-scale models of single board computers, though we have featured one or two working small-scale computer models.

Thanks [Michael K Castor] and [Christian Moist] for sharing their project with us.