Vintage Computers With A Real Turbo

November 3, 2021 by Bryan Cockfield 42 Comments

In prior centuries, it was common practice to tie the operation of a program to a computer’s clock speed. As computers got faster and faster, the programs tied to that slower clock speed sometimes had trouble running. To patch the issue temporarily, some computers in the early 90s included a “TURBO” button which actually slowed the computer’s clock speed down in order to help older software run without breaking in often unpredictable ways. [Ted Fried] decided that he would turn this idea on its head, though, by essentially building a TURBO button into the hardware of old computers which would greatly increase the execution speed of these computers without causing software mayhem.

To accomplish this, he is running CPU emulators on Teensys (Teensies?), but they are configured to be a drop-in replacement for the physical CPU of several retro computers such as the Apple II, VIC-20, and Commodore 64 rather than an emulator for an entire system. It can be configured to run either in cycle-accurate mode, making it essentially identical to the computer’s original hardware, or it can be placed into an accelerated mode to take advantage of the Teensy 4.1’s 800 MHz processor, which is orders of magnitude faster than the original hardware. This allows (most of) the original hardware to still be used while running programs at wildly faster speeds without needing to worry about any programming hiccups due to the increased clock speed.

The video below demonstrates [Ted]’s creation running in an Apple II but he has several other cores for other retro computers. It’s certainly a unique way to squeeze more computing power out of these antique machines. Some Apple II computers had a 4 MHz clock which seems incredibly slow by modern standards, so the 800 MHz Teensy would have been considered wizardry by the standards of the time, but believe it or not, it’s actually necessary to go the other direction for some applications and slow this computer down to a 1 MHz crawl.

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An Emulator For OBP, The Spaceflight Computer From The 1960s

November 1, 2021 by Donald Papp 9 Comments

[David Given] frequently dives into retrocomputing, and we don’t just mean he refurbishes old computers. We mean things like creating a simulator and assembler for the OBP spaceflight computer, which was used in the OAO-3 Copernicus space telescope, pictured above. Far from being a niche and forgotten piece of technology, the On-Board Processor (OBP) was used in several spacecraft and succeeded by the Advanced On-board Processor (AOP), which in turn led to the NASA Standard Spaceflight Computer (NSSC-1), used in the Hubble Space Telescope. The OBP was also created entirely from NOR gates, which is pretty neat.

One thing [David] learned in the process is that while this vintage piece of design has its idiosyncrasies, in general, the architecture has many useful features and is pleasant to work with. It is a bit slow, however. It runs at a mere 250 kHz and many instructions take several cycles to complete.

Sample of the natural-language-looking programming syntax for the assembler. (Example from page 68 of the instruction set manual for the OBP.)

One curious thing about the original assembler was documentation showing it was intended to be programmed in a natural-language-looking syntax, of which an example is shown here. To process this, the assembler simply mapped key phrases to specific assembly instructions. As [David] points out, this is an idea that seems to come and go (and indeed the OBP’s successor AOP makes no mention whatsoever of it, so clearly it “went”.) Since a programmer must adhere to a very rigid syntax and structure anyway to make anything work, one might as well just skip dealing with it and write assembly instructions directly, which at least have the benefit of being utterly unambiguous.

We’re not sure who’s up to this level of detail, but embedded below is a video of [David] coding the assembler and OBP emulator, just in case anyone has both an insatiable vintage thirst and a spare eight-and-a-half hours. If you’d prefer just the files, check out the project’s GitHub repository.

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A vintage supercomputer with unique dual screen display

VCF East 2021: The Early Evolution Of Personal Computer Graphics

October 29, 2021 by Chris Wilkinson 12 Comments

The evolution of computer graphics is something that has been well documented over the years, and it’s a topic that we always enjoy revisiting with our retrocomputing readers. To wit, [Stephen A. Edwards] has put together an impressively detailed presentation that looks back at the computer graphics technology of the 1960s and 70s.

The video, which was presented during VCF East 2021, goes to great lengths in demystifying some of the core concepts of early computer graphics. There’s a lot to unpack here, but naturally, this retrospective first introduces the cathode-ray tube (CRT) display as the ubiquitous technology that supported computer graphics during this time period and beyond. Building from this, the presentation goes on to demonstrate the graphics capabilities of DEC’s PDP-1 minicomputer, and how its striking and surprisingly capable CRT display was the perfect choice for playing Spacewar!

As is made clear in the presentation, the 1960s featured some truly bizarre concepts in regards to cutting edge computer graphics, such as Control Data Corporation’s 6600 mainframe and accompanying vector-based dual-CRT video terminal, which wouldn’t look out of place on the Death Star. Equally strange at the time was IBM’s 2260 video data terminal, which used a ‘sonic delay line’ as a type of rudimentary video memory, using nothing but coiled wire, transducers and sound itself to store character information following a screen refresh.

These types of hacks were later replaced by solid state counterparts during the microcomputer era. The video concludes with a look back at the ‘1977 trinity’ of microcomputers, namely the Apple II, Commodore PET and TRS-80. Each of these microcomputers handled graphics in a slightly different way, and it’s in stark contrast to today’s largely homogenised computer graphics landscape.

There’s a lot more to this great retrospective, so make sure to check out the video below. When you’re finished watching, make sure to check out our other coverage of VCF 2021, including some great examples of computer preservation and TTL-based retrocomputing.

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Chip Tester Knows If Your Old Chips Are Working

October 23, 2021 by Al Williams 6 Comments

[Noel’s Retro Lab] has looked at retro chip testers before, but in a recent video you can see below he’s looking at the Chip Tester Pro, a preassembled chip tester for vintage chips, especially those used in Commodore computers. The device looks good on the surface with a form factor like a calculator or cell phone, an LCD display, and a 48 pin ZIF socket.

The user interface is pretty simple. A rotary encoder and a big red button are about it. However, there are also some headers where you have to use jumpers to wire signals to the chip. The firmware gives you specific directions, but it is reminiscent of programming old punchcard machines with jumper wires. Luckily, it looks like you only route the power to the device so you don’t have many wires to connect (usually two or three).

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Refining The Greatest Joystick Of The 1980s

October 20, 2021 by Tom Nardi 24 Comments

The Competition Pro joystick is often considered to be the pinnacle of input devices, at least as far as the 1980s gaming goes. But the design isn’t perfect, and time hasn’t been kind to certain aspects of its mechanism. For example, the large rubber disc used to keep the stick centered on early generations of the hardware will invariably be hardened up on any surviving specimens. Looking to return these classic controllers to their former glory, and then some, [mageb] has released a number of 3D printed modifications for the Competition Pro that should be of great interest to the vintage gamer.

First and foremost is the deletion of the original rubber disc for a new spring mechanism. Even if this is the only modification you do, [mageb] says you’ll already have a better and longer-lasting joystick to show for it. But if you want to continue with the full rebuild, be aware that there’s no going back to stock. Once you start cutting the original parts, you’re committed to taking it all the way.

Assuming you’re not afraid to get your hands dirty, the next step is cutting the metal contacts from the bottom of the face buttons so they’ll work with the new microswitch array he’s designed. Each button gets its switch, and four handle movement of the joystick. You can try out different switches to adjust the feel of the joystick, but [mageb] assures us that he’s already done the research and put the best quality switches in the bill of materials.

The end result is a Competition Pro joystick that looks more or less the same from the outside, but is considerably improved internally. That’s always a win in our books, though we’re sure somebody out there is going to get mad that the brittle old rubber disc wasn’t sent to the Smithsonian.

Vintage Computer Festival East Reboots This Weekend

October 6, 2021 by Tom Nardi 13 Comments

We don’t have to tell the average Hackaday reader that the last two years have represented a serious dry spell for the type of in-person events that our community has always taken for granted. Sure virtual hacker cons have their advantages, but there’s nothing quite like meeting up face to face to talk shop with like-minded folks and checking out everyone’s latest passion project.

Luckily for classic computer aficionados, especially those on the East Coast of the United States, the long wait is about to end. After being forced to go virtual last year, Vintage Computer Festival East will once again be opening their doors to the public from October 8th to the 10th at the InfoAge Science & History Center in Wall, New Jersey. Attendees will need to wear a mask to gain access to the former Camp Evans Signal Corps R&D laboratory, but that’s a small price to pay considering the impressive list of exhibits, presentations, and classes being offered.

In fact, it’s shaping up to be the biggest and best VCF East yet. The Friday classes cover a wide range of topics from CRT repair to implementing a basic video controller with a FPGA, and the list of speakers include early computer luminaries such as Michael Tomczyk, the Product Manager for the VIC-20, and Adventure International founder Scott Adams. A little birdie even tells us that if you bring your copy of Back into the Storm, our very own Bil Herd will be sign it for you after his talk on the history of the Commodore wraps up Saturday evening.

If you’d rather get hands-on you can always take a walk over to the Computer Deconstruction Laboratory, InfoAge’s on-site hackerspace. Glitch Works will be on hand with several popular kits such as the XT-IDE, an 8-bit ISA adapter that lets you connect (relatively) modern drives to classic machines, and the R6501Q/R6511Q Single Board Computer. A bit rusty with the iron and would rather start on something a little easier? Not to worry. Neil Cherry, a staple of the Hackaday comment section since before we switched to color pictures, will be instructing hackers young and old in the ways of the flux during his all-day soldering classes.

Of course, no VCF trip is truly complete until you’ve searched for treasure in the consignment room. The space has been expanded for 2021, and considering how long folks have had to clean out their attics and garages thanks to the pandemic, we’re expecting a bumper crop of interesting hardware to wade through. If the turnout for the VCF Swap Meet in April was any indication, we’d suggest bringing some extra cash with you.

As a proud sponsor of the 2021 Vintage Computer Festival East, Hackaday will naturally be bringing you a first-hand account of the overall event as well as a deeper look into some of the incredible exhibits on display in the very near future. But words and pictures on a page can only go so far. If you’ve grown tired of virtual events and are looking to peek your head out, we can guarantee a trip to InfoAge this weekend will be well worth the gas money for anyone within driving distance.

Automatic Microfiche Scanner Digitizes Docs

September 17, 2021 by Tom Nardi 18 Comments

While the concept might seem quaint to us today, microfiche was once a very compelling way to store and distribute documents. By optically shrinking them down to just a few percent of their original size, hundreds of pages could be stored on a piece of high-resolution film. A box of said films could store the equivalent of several gigabytes of text and images, and reading them back only required a relatively simple projection machine.

As [Joerg Hoppe] explains in the write-up for his automatic microfiche scanner, companies such as Digital Equipment Corporation (DEC) made extensive use of this technology to distribute manuals, schematics, and even source code to their service departments in the 70s and 80s. Luckily, that means hard copies of all this valuable information still exist in excellent condition decades after DEC published it. The downside, of course, is that microfiche viewers aren’t exactly something you can pick up at the local Big Box electronics store these days. To make this information accessible to current and future generations, it needs to be digitized.

The camera panning over a full DEC microfiche sheet.

[Joerg] notes there are commercial services that would do this for you, but the prices are just too high to be practical for the hobbyist. The same for turn-key microfiche scanners. Which is why he’s developed this hardware and software system specifically to digitize DEC documents. The user enters in the information written on the top of the microfiche into the software, and then places it onto the machine itself which is based on a cheap 3D printer.

The device moves a Canon DSLR camera and appropriate magnifying optics in two dimensions over the film, using the Z axis to fine-tune the focus, and then commands the camera to take an image of each page. These are then passed through various filters to clean up the image, and compiled into PDFs that can be easily viewed on modern hardware. The digital documents can be further run though optical character recognition (OCR) so the text can be easily searched and manipulated. In the video after the break you can see that the whole process is rather involved, but once the settled into the workflow, [Joerg] says his scanner can digitize 100 pages in around 10 minutes.

A machine like this is invaluable if you’ve got a trove of microfiche documents to get through, but if you’ve just got a sheet or two you’d like to take a peek at, [CuriousMarc] put together a simple rig using a digital microscope and a salvaged light box that should work in a pinch.

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