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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One Man’s Awesome Collection Of Projects Done Over A Lifetime

[Robert Glaser] kept all his projects, all of them, from the 1960s to now. What results is a collection so pure we feel an historian should stop by his house, if anything, to investigate the long-term effects of the knack.

He starts with an opaque projector he built in the third grade, which puts it at 1963. Next is an, “idiot box,” which looks suspiciously like “the Internet”, but is actually a few relaxation oscillators lighting up neon bulbs. After that, the condition really sets in, but luckily he’s gone as far as to catalog them all chronologically.

We especially enjoyed the computer projects. It starts with his experiences with punch cards in high school. He would hand-write his code and then give it to the punch card ladies who would punch them out. Once a week, a school-bus would take the class to the county’s computer, and they’d get to run their code. In university he got to experience the onset of UNIX, C, and even used an analog computer for actual work.

There’s so much to read, and it’s all good. There’s a section on Ham radio, and a very interesting section on the start-up and eventual demise of a telecom business. Thanks to reader, [Itay Ramot], for the tip!

Coolest, but Least Secure, Security Device

[Matikas] apparently forgets to lock the screen on his computer when he gets up to grab a coffee. And he apparently works with a bunch of sharks: “If you don’t [lock it], one of your colleagues will send email to the whole company that you invite them to get some beer (on your bill, of course).” Not saying we haven’t done similar, mind you. Anyway, forgetting to lock your screen in an office environment is serious business.

So [Matikas] built a great system that remotely types the keystrokes to lock his screen, or unlock it with his password. An off-the-shelf 433 MHz keyfob is connected to an Arduino micro that simulates a keyboard attached to his computer. It’s a simple system, but it’s a great effect. (See the video demo, below.)

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The Man Who Didn’t Invent The Personal Computer

[John Blankenbaker] did not invent the personal computer. Museums, computer historians, and authors have other realities in mind when they say [John]’s invention, the KENBAK-1, was the first electronic, commercially available computer that was not a kit, and available to the general population.

In a way, it’s almost to the KENBAK’s detriment that it is labelled the first personal computer. It was, after all, a computer from before the age of the microprocessor. It is possibly the simplest machine ever sold and an architecturally unique machine that has more in common with the ENIAC than any other machine built in the last thirty years..

The story of the creation of this ancient computer has never been told until now. [John], a surprisingly spry octogenarian, told the story of his career and the development of the first personal computer at the Vintage Computer Festival East last month. This is his story of not inventing the personal computer.

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Chess Computers Improve Since 90s

The AlphaGo computer has been in the news recently for beating the top Go player in the world in four out of five games. This evolution in computing is a giant leap from the 90s when computers were still struggling to beat humans at chess. The landscape has indeed changed, as [Folkert] shows us with his chess computer based on a Raspberry Pi 3 and (by his own admission) too many LEDs.

The entire build is housed inside a chess board with real pieces (presumably to aid the human player) and an LED on every square. When the human makes a move, he or she inputs it into the computer via a small touch screen display. After that, the computer makes a move, indicated by lighting up the LEDs on the board and printing the move on the display. The Raspberry Pi is running the embla chess program, which has an Elo strength of about 1600.

While the computer isn’t quite powerful enough to beat Magnus Carlsen, we can only imagine how much better computers will be in the future. After all, this credit-card sized computer is doing what supercomputers did only a few decades ago. With enough Raspberry Pis, you might even be able to beat a grandmaster with your chess computer. Computer power aside, think of the advancements in fabrication technology (and access to it) which would have made this mechanical build a wonder back in the 90s too.

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Museum Shows Off Retro Malware

There’s some debate on which program gets the infamous title of “First Computer Virus”. There were a few for MS-DOS machines in the 80s and even one that spread through ARPANET in the 70s. Even John von Neumann theorized that programs might one day self-replicate. To compile all of these early examples of malware, and possibly settle this question once and for all, [Mikko Hypponen] has started collecting many of the early malware programs into a Museum of Malware.

While unlucky (or careless) users today are confronted with entire hard drive encryption viruses (or worse), a lot of the early viruses were relatively harmless. Examples include Brain which spread via floppy disk, the experimental ARPANET virus, or Elk Cloner which, despite many geniuses falsely claiming that Apples are immune to viruses, infected Mac computers of the 80s. [Mikko] has collected many more from this era that can be downloaded or demonstrated in a browser.

Retrocomputing is an active community, with users keeping gear of this era up and running despite it being 30+ years old. This software, while malicious at the time, is a great look into what the personal computing world was like in its infancy. And don’t forget, if you have a beige computer from a bygone era, you can always load up our Retro Page.

Thanks to [chad] for the tip!

Open Source… Windows?

There’s a lot to be said for open source software. The ability to change code to suit one’s needs, the fact that security vulnerabilities can be easier to find, and the overall transparency are just the tip of the iceberg when it comes to the strengths of using open source software. And, while Microsoft is no Apple when it comes to locking down their source code, their operating system is still, unfortunately, closed.

Don’t despair, though! There is a project out there that aims to change this. No, they’re not stealing anything or breaking into any computers to obtain Microsoft’s code. They’re writing their own version of Windows called ReactOS that aims to be binary-compatible with Windows. The software has been in development for over a decade, but they’re ready to release version 0.4 which will bring USB, sound, networking, wireless, SATA, and many more features to the operating system.

While ReactOS isn’t yet complete for everyday use, the developers have made great strides in understanding how Windows itself works. There is a lot of documentation coming from the project regarding many previously unknown or undocumented parts of Windows, and with more developers there could be a drop-in replacement for Windows within a few years. It’s definitely worth a shot if you fondly remember the frontier days of Linux where doing things like reading information on a CD required extensive experience using the terminal. If this is a little too much, though, there are other unique operating systems out there to investigate.

Thanks for the tip, [Matt]!