Little Emulators Do 8 Bits At A Time

November 20, 2018 by Al Williams 9 Comments

Have you ever wondered how many, for example, Commodore 64s it would take to equal the processing power in your current PC? This site might not really answer that, but it does show that your machine can easily duplicate all the old 8-bit computers from Commodore, Sinclair, Acorn, and others. By our count, there are 86 emulators on the page, although many of those are a host machine running a particular application such as Forth or Digger.

If you are in the US, you might not recognize all the references to the KC85, this was an East German computer based on a Z80 clone. Very few of these were apparently available for personal purchase, but they were very popular in schools and industry. These were made by Robotron, and there are some other Robotron models on the page, too.

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Adding Linux To A PDP-11

November 15, 2018 by Brian Benchoff 14 Comments

The UNIBUS architecture for DEC’s PDPs and Vaxxen was a stroke of genius. If you wanted more memory in your minicomputer, just add another card. Need a drive? Plug it into the backplane. Of course, with all those weird cards, these old UNIBUS PDPs are hard to keep running. The UniBone is the solution to this problem. It puts Linux on a UNIBUS bridge, allowing this card to serve as a memory emulator, a test console, a disk emulator, or any other hardware you can think of.

The key to this build is the BeagleBone, everyone’s second-favorite single board computer that has one feature the other one doesn’t: PRUs, or a programmable real-time unit, that allows you to blink a lot of pins very, very fast. We’ve seen the BeagleBone be used as Linux in a terminal, as the rest of the computer for an old PDP-10 front panel and as the front end for a PDP-11/03.

In this build, the Beaglebone’s PRU takes care of interfacing to the UNIBUS backplane, sending everything to a device emulator running as an application. The UniBone can be configured as memory or something boring, but one of these can emulate four RL02 drives, giving a PDP-11 an amazing forty megabytes of storage. The real killer app of this implementation is giving these emulated drives a full complement of glowing buttons for load, ready, fault, and write protect, just like the front of a real RL02 drive. This panel is controlled over the I2C bus on the Beaglebone, and it’s a work of art. Of course, emulating the drive means you can’t use it as the world’s largest thumb drive, but that’s a small price to pay for saving these old computers.

Supercon Badge Hardware Hacking: Here’s What To Bring

October 25, 2018 by Roger Cheng 29 Comments

Hackaday Superconference is just a week away (precious few tickets remain), a celebration of all things Hackaday, which naturally includes creative projects making the most of their hardware. Every attendee gets a platform for hacking in the form of the conference badge.

To make the most of your badge hacking fun, plan ahead so you will have the extra components and the tools you need. At the most basic, bring along a serial to USB cable and a PIC programmer. These are common and if you don’t own them, ask around and you will likely be able to borrow them. Now is also the time to put in a parts order for any components you want to use but don’t have on hand!

The badge is hackable without any extras, but it’s designed for adding hardware and hacking the firmware. We’re excited to see what you can do with it. We gave an overview of this retro themed pocket computer a few days ago, today we’re inviting you to exploit its potential for your hardware hacks.

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The Supercon Badge Is A Freakin’ Computer

October 17, 2018 by Mike Szczys 55 Comments

It hangs around your neck, comes with the cost of admission, and would blow away a desktop computer from the 1980’s. This is the Hackaday Superconference badge and you can get your hands on one for the price of admission to the ultimate hardware conference.

Everyone through the door gets one of these badges featuring a 320 x 240 color display, a full qwerty keyboard, and limitless hacking potential! The stock firmware runs a BASIC interpreter, the CP/M operating system, and includes games and Easter Eggs. It’s a giant playground, and we want to see what you can do with this custom hardware during the three days of Supercon. Get your ticket now, then join me after the break for a demo video and plenty more info.

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Circuit Bending A TV For Better Input

October 15, 2018 by Brian Benchoff 55 Comments

If you haven’t noticed, CRTs are getting hard to find. You can’t get them in Goodwill, because thrift stores don’t take giant tube TVs anymore. You can’t find them on the curb set out for the trash man, because they won’t pick them up. It’s hard to find them on eBay, because no one wants to ship them. That’s a shame, because the best way to enjoy old retrocomputers and game systems is with a CRT with RGB input. If you don’t already have one, the best you can hope for is an old CRT with a composite input.

But there’s a way. [The 8-Bit Guy] just opened up late 90s CRT TV and modded it to accept RGB input. That’s a monitor for your Apple, your Commodore, and a much better display for your Sega Genesis.

There are a few things to know before cracking open an old CRT and messing with the circuits. Every (color) CRT has three electron guns, one each for red, green, and blue. These require high voltage, and in CRTs with RGB inputs you’re looking at a circuit path that takes those inputs, amplifies them, and sends them to the gun. If the TV only has a composite input, there’s a bit of circuitry that takes that composite signal apart and sends it to the guns. In [8-bit guy]’s TV — and just about every CRT TV you would find from the mid to late 90s — there’s a ‘Jungle IC’ that handles this conversion, and most of the time there’s RGB inputs meant for the on-screen display. By simply tapping into those inputs, you can add RGB inputs with fancy-schmancy RCA jacks on the back.

While the actual process of adding RGB inputs to a late 90’s CRT will be slightly different for each individual make and model, the process is pretty much the same. It’s really just a little bit of soldering and then sitting back and playing with old computers that are finally displaying the right colors on a proper screen.

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Ants, Dirt, Rain, And The Commodore 64 That Wouldn’t Quit

October 3, 2018 by Dan Maloney 34 Comments

Some electronics gear is built for the roughest conditions. With rugged steel cases, weatherproof gaskets, and cables passing through sealed glands, these machines are built to take the worst that Mother Nature can throw at them, shrugging off dust, mud, rain, and ice. Consumer-grade computers from the start of the home PC era, however, are decidedly not such machines.

Built to a price point and liable to succumb to a spilled Mountain Dew, few machines from that era that received any kind of abuse lived to tell the tale. Not so this plucky Commodore 64C, which survived decades exposed to the elements. As [Adrian Black] relates in the video below, this machine was on a scrap heap in an Oregon field, piled there along with other goodies by one of those “pickers” that reality TV loves so much. The machine was a disaster. It hadn’t been soaked in oil, but it was loaded with pine needles and an ant colony. The worst part, though, was the rust. The RF shielding had corroded into powder in some places, leaving reddish rust stains all over the place. Undeterred, [Adrian] gave the machine a good bath, first in water, then in isopropanol. Liberal applications of Deoxit helped with header connections, enough to see that the machine miraculously booted. It took some finagling, especially with the 6526 I/O controller, but [Adrian] was eventually able to get everything on the motherboard working, even the sound chip.

Whether this machine survived due to good engineering or good luck is debatable, but it’s a treat to see it come back to life. We hope a full restoration is in the works, not least as a way to make up for the decades of neglect.

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Fixing An IBM 1401 Computer To Get It Printing Again

September 20, 2018 by Steven Dufresne 10 Comments

The IBM 1401 is a classic computer which IBM marketed throughout the 1960s, late enough for it to have used transistors rather than vacuum tubes, which is probably a good thing for this story. For small businesses, it was often used as their main data processing machine along with the 1403 printer. For larger businesses with mainframes, the 1401 was used to handle the slower peripherals such as that 1403 printer as well as card readers.

The Computer History Museum in Mountain View, CA has two working 1401s as well as at least one 1403 printer, and recently whenever the printer printed out a line, the computer would report a “print check” error. [Ken Shirriff] was among those who found and fixed the problem and he wrote up a detailed blog entry which takes us from the first test done to narrow down the problem, through IBM’s original logic diagrams, until finally yanking out the suspect board and finding the culprit, a germanium transistor which likely failed due to corrosion and an emitter wire that doesn’t look solidly connected. How do they know that? In the typical [Ken]-and-company style which we love, they opened up the transistor and looked at it under a microscope. We get the feeling that if they could have dug even deeper then they would have.

If you’re unfamiliar with the work of this team who maintain the machines at the museum, you’ll want to read up on how they recently got a 1401 to run FORTRAN II code.