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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VCF East 2021: Preserving Heathkit’s 8-Bit Computers

October 27, 2021 by Tom Nardi 39 Comments

To say the Heathkit name is well known among Hackaday readers would be something of an understatement. Their legendary kits launched an untold number of electronics hobbies, and ultimately, plenty of careers. From relatively simple radio receivers to oscilloscopes and televisions, the company offered kits for every skill level from the post-war era all the way up to the 1990s.

So it’s hardly a surprise that in 1977, seeing the success of early home computers like the Altair 8800 and IMSAI 8080, Heathkit decided to join the fray with a computer kit of their own. But by that point the home computing market had started to shift from a hobbyist’s pursuit to something the whole family could enjoy. Compared to the Apple II and TRS-80, both of which also launched in 1977, Heathkit’s machine seemed like the product of a bygone era.

While it might not have gained the notoriety of the microcomputers it was designed to compete with, the Heathkit H8 is certainly not forgotten. Tucked away in a corner at the 2021 Vintage Computer Festival East was an impressive exhibit dedicated to the Society of Eight-Bit Heath Computerists (SEBHC) called Heathkit: Keeping the Legacy Alive. Presented by Glenn Roberts, this collection of original and modern hardware demonstrated the incredible lengths to which this group of passionate Heathkit owners have gone to not just preserve the memory of these often overlooked computers, but to continue to improve upon the kit’s unique design.

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Classic 80s Text-To-Speech On Classic 80s Hardware

October 26, 2021 by Bryan Cockfield 34 Comments

Those of us who were around in the late 70s and into the 80s might remember the Speak & Spell, a children’s toy with a remarkable text-to-speech synthesizer. While it sounds dated by today’s standards, it was revolutionary for the time and was riding a wave of text-to-speech functionality that was starting to arrive to various computers of the era. While a lot of them used dedicated hardware to perform the speech synthesis, some computers were powerful enough to do this in software, but others were not quite able. The VIC-20 was one of the latter, but thanks to an ESP8266 it has been retroactively given this function.

This project comes to us from [Jan Derogee], a connoisseur of this retrocomputer, and builds on the work by [Earle F. Philhower] who ported the retro speech synthesis software known as SAM from assembly to C which made it possible to run on the ESP8266. Audio playback is handled on the I2S port, but some work needed to be done to get this to work smoothly since this port also handles the communication with the VIC-20. Once this was sorted out, a patch was made to be able to hear the computer’s audio as well as the speech synthesizer’s. Finally, a serial command interface was designed by [Jan] which allows for control of the module.

While not many of us have VIC-20s sitting at home, it’s still an interesting project that shows the broad scope of a small and inexpensive chip like the ESP8266 which would have had a hefty price tag back in the 1980s. If you have other 80s hardware laying around waiting to be put to work, though, take a look at this project which brings new vocabulary words to that old classic Speak & Spell.

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VCF East 2021: Novasaur TTL Computer Sets The Bar

October 25, 2021 by Tom Nardi 12 Comments

There was certainly no shortage of unique computers on display at the 2021 Vintage Computer Festival East; that’s sort of the point. But even with the InfoAge Science and History Museum packed to the rafters with weird and wonderful computing devices stretching back to the very beginning of the digital age, Alastair Hewitt’s Novasaur was still something of an oddity.

In fact, unless you knew what it was ahead of time, you might not even recognize it as a computer. Certainly not a contemporary one, anyway. There’s nothing inside its Polycase ZN-40 enclosure that looks like a modern CPU, a bank of RAM, or a storage device. Those experienced with vintage machines would likely recognize the tight rows of Advanced Schottky TTL chips as the makings of some sort of computer that predates the 8-bit microprocessor, but its single 200 mm x 125 mm (8 in x 5 in) board seems far too small when compared to the 1970s machines that would have utilized such technology. So what is it?

Inspired by projects such as the Gigatron, Alastair describes the Novasaur as a “full-featured personal computer” built using pre-1980 components. In his design, 22 individual ICs stand in for the computer’s CPU, and another 12 are responsible for a graphics subsystem that can push text and bitmapped images out over VGA at up to 416 x 240. It has 512 K RAM, 256 K ROM, and is able to emulate the Intel 8080 fast enough to run CP/M and even play some early 80s PC games.

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An Arduino Nano connected to a portable tape recorder

Audio Tape Interface Revives Microcassettes As Storage Medium

October 20, 2021 by Robin Kearey 37 Comments

In the early 1980s cassette tapes were the standard storage medium for home computer users; readers of a certain age will remember fiddling with audio jacks, tape counters and signal levels, then waiting for several minutes while a program (hopefully) loaded correctly. While most people happily upgraded to much more reliable floppy disks, [Zack Nelson] decided to go back in time and add a suitably classic storage medium to a retrocomputing project, in the form of a cassette interface. The cassette player he had available was a Pearlcorder L400, which uses the smaller microcassette instead of the familiar audio tapes used in your Walkman or boombox.

[Zack] designed the entire thing from the ground up: first he decided to use differential Manchester encoding, which provides immunity against common disturbances like speed variations (which cause wow and flutter). The data is encoded in the frequency range from 1 kHz to 2 kHz, which suits the bandwidth of the cassette player. Next, he designed the interface between the computer and the tape recorder; built from an op-amp and a comparator with a handful of discrete components, it filters the incoming signal and clips it to provide a clean digital signal to be read out directly by the computer.

The system is demonstrated by hooking it up to an Arduino Nano, which reads out the data stream at about 3000 baud. The noise it makes should bring back memories to anyone brought up with the “PRESS PLAY ON TAPE” message; if it inspires you to make your own, we’re happy to report that full schematics and source code are available. [Zack] is not the first one to make his own cassette interface; we’ve seen a somewhat more complicated analog design before, as well as one based on an FPGA.

VCF East Roars Back To Life

October 19, 2021 by Tom Nardi 15 Comments

It didn’t take long to realize that the 2021 Vintage Computer Festival East — returning to the InfoAge Science and History Museum in Wall, New Jersey after being held virtually last year — was a massive success. In fact, the first clue came before I even got out of my car. When a volunteer came up to my window to apologetically explain that the primary parking lot was already full and I’d have to drive down the road to an overflow lot, there was no question about it; a whole lot of folks were more than ready to shake off those pandemic blues and get back to business.

They certainly picked a great event for it. While VCF East has always been a highlight of the East Coast hacker’s year, it was obvious things were really turned up to the max for this much-anticipated return to an in-person festival. With respect to all those involved in previous events, things just felt more cohesive and better organized this time around.

Veteran attendees I spoke to all felt like they were witnessing the event going through an evolutionary change into something bigger and better, while first time fliers were impressed with the buzz of activity and breadth of what was on display. In short, admiration for the event and the people working behind the scenes to make it possible was unanimous.

It’s simply not possible to adequately summarize a multi-day event like VCF East in a single post, so I won’t try to. This article, and the ones to follow it, serve only to document some of the highlights from my own personal time wandering through the sprawling InfoAge campus. Ultimately, there’s no real substitute for making the trip to Wall, NJ and experiencing this incredible event for yourself. But if that’s not an option for you, hopefully the following will give you a little taste of what the Vintage Computer Federation labors so hard over every year.

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POLF: Retro 3D Game Uses Only A Character Display

October 18, 2021 by Donald Papp 11 Comments

Got a retrocomputing itch? So does [David Given], and luckily for us all he indulged it by writing POLF: a first-person 3D game for the Commodore PET that uses only the system’s 40×25 text mode character display for visuals. It’s a fantastic achievement, considering that the 80s-era computer boasts 32 kB of memory and doesn’t even have a graphical display.

Each level in POLF is a small, maze-like room in which one’s goal is to play a sort of cross between billiards and golf, aiming to move the round “ball” object into the square “hole” object. The 3D view is rendered using raycasting, which is a way of efficiently drawing a workable 3D perspective using limited resources. Raycasting can only do so much, but as a method it works fantastically within its limitations, and there are useful tutorials out there that lay the process bare.

The GitHub repository for the project is here, and it should run on any 40-column screen PET with at least 16 kB of RAM. Watch it in action in the video, embedded below. (Hint: the little bar graphs under the compass headings at the bottom of the screen represent the player’s proximity to the ball and hole objects. )

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