Looking At Fortran In 100 Seconds

July 16, 2022 by Al Williams 36 Comments

Usually, when we are talking about old computers, we are thinking of BASIC interpreters. But [Fireship] reminds us that it was originally Fortran and promises to give you the essentials in 100 seconds. We didn’t think you could do much in that short amount of time, but we have to admit that they did a pretty good job.

Of course, it doesn’t hurt that we know Fortran — you probably aren’t going to be able to put it on your resume after watching this video. On the other hand, we were impressed with how much they did squeeze in. If you haven’t touched Fortran since the 1960s and 1970s, you should know that it has changed. Pointers, dynamic memory allocation, and even objects are all possible. It is still a very capable language and very adept at crunching large sets of numbers. Besides, there are many sophisticated algorithms you can borrow from decades of Fortran development.

If you decide you want to have a go, there is, of course, GNU Fortran. Honestly, as much time as we spent writing Fortran in years past, we don’t recommend it for new job prospects. But if you have some period hardware and want an authentic experience, it might just be the way to go. Or, just fire up a browser if you want to play.

Not everyone agrees, though, that Fortran is on the wane. There are efforts to bring it even more up to date. You can even use it for web development.

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Your Own IBM Mainframe (or Vax, Or Cray…) The Easy Way

June 19, 2022 by Al Williams 35 Comments

If you want the classic experience of working with an IBM mainframe or another classic computer like a DEC VAX, you have a few choices. You could spend a lot of money trying to find one, transport it, and refurbish it. But, of course, most of us will settle for an emulator. While there are great emulators out there, most of the time you aren’t interested in running just the bare machine — you want the operating systems, the compilers, and the other software that made these machines so interesting. Running your three lines of machine code isn’t as much fun as playing hunt the wumpus or compiling some Fortran IV code. Unfortunately, finding copies of all this old software can be daunting. But thanks to the efforts of [Rattydave], you can do it with no problems at all. The secret? Pre-built docker images that have everything you need in one place.

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Repairing An HDMI Adapter Doesn’t Go So Well

May 16, 2022 by Al Williams 27 Comments

[Adrian] has a lot of retrocomputers, so he uses an RGB to HDMI converter to drive modern monitors. In particular, he has a box that uses a programmable logic chip to read various RGB signals and ships them to a Raspberry Pi Zero to drive the HDMI output. Sounds great until, of course, something goes wrong.

A converter that had worked stopped working due to a bad board with the programmable logic chip on it. Unlike the retrocomputers, this board has little tiny surface mount components. A little analysis suggested that some of the chip pins were not accepting inputs.

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Striping A Disk Drive The 1970 Way

May 16, 2022 by Al Williams 38 Comments

These days, mass storage for computers is pretty simple. It either uses a rotating disk or else it is solid state. There are a few holdouts using tape, too, but compared to how much there used to be, tape is all but dead. But it wasn’t that long ago that there were many kinds of mass storage. Tapes, disks, drums, punched cards, paper tape, and even stranger things. Perhaps none were quite so strange though as the IBM 2321 Data Cell drive — something IBM internally called MARS.

What is a data cell you might ask? A data cell was a mass storage device from IBM in 1964 that could store about 400 megabytes using magnetic strips that looked something like about a foot of photographic film. The strips resided inside a drum that could rotate. When you needed a record, the drum would rotate the strip you needed to the working part and an automated process would remove the strip in question, wrap it around a read/write head and then put it back when it was done.

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Will MiSTer Fool You Into Learning FPGAs?

May 9, 2022 by Elliot Williams 45 Comments

What’s the killer app for FPGAs? For some people, the allure is the ultra-high data throughput for parallelizable tasks, which can enable some pretty gnarly projects. But what if you’re just starting out? How about 1980s style video games?

The MiSTer FPGA project created a bit of FPGA hardware that makes it easy to build essentially any old school video game or computer platform. That’s a massive clean slate. Of course, you can simply download someone else’s Atari ST or Commodore 64 setup and load it up, but if you want to learn FPGAs while recreating old-school video game machines, you’re going to want to get your hands dirty.

[Mister Retro Wolf] started up a video series last winter (trailer embedded below) where he’s embarked on a project to recreate a classic video game machine from the ground up using the MiSTer FPGA platform. In particular, he’s going to recreate the Namco Tank Battalion arcade game, from the schematics, in Verilog.

This is literally building a 6502-based video game machine from scratch (in gateware), so if you’re interested in retrocomputing or FPGAs, you’ll have something to learn here. He’s gotten through the CPU, screen, tilemap graphics, and memory so far, but it’s not done yet. To follow along, get yourself some hardware and you can probably catch up.

We’ve covered the MiSTer FPGA project before, of course, because we think it’s cool. And if a video game arcade machine is going to be your gateway drug into the seedy world of programmable gates, then so be it.

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Learning Obsolete Technology

May 7, 2022 by Elliot Williams 33 Comments

Tom Nardi and I were talking about his trip to the Vintage Computer Festival on the podcast, and he admitted to not having been a retrocomputer aficionado before his first trip. But he ended up keying some binary machine code into some collection of archaic silicon, and he got it. In the same episode, the sound of the week was a Strowger switch — the old electromechanical “brain” of telephone switching centers of old. The sample I used was from Sam of Look Mum No Computer on YouTube, who got one for his museum and thinks it’s just awesome.

Why do people like this kind of old (obsolete?) tech? It’s certainly not because it’s overwhelmingly capable — the giant old switch is replaced easily by a stack of silicon, and don’t even get me started on the old blinkenlights computer that Tom was keying on. In both of these cases, the people are significantly younger than the tech they’re playing around with, so that rules out nostalgia. What’s left?

I think it’s that sometimes the older technology is more immediate, more understandable, more tangible, and that resonates with people. In a time when we all have wonder devices that can do anything, programmed in languages that are pleasant, using libraries that are nothing short of magical in terms of making difficult things easy, understanding how things work down to the ground is a rare commodity.

But it’s a strange position to find ourselves in, technologically, where there’s almost necessarily a trade-off between the usefulness and functionality of a device with the ability to understand fundamentally how it works.

Paper Tape Reader Self-calibrates, Speaks USB

April 16, 2022 by Donald Papp 22 Comments

Input devices consisting of optical readers for punched paper tape have been around since the earliest days of computing, so why stop now? [Jürgen]’s Paper Tape Reader project connects to any modern computer over USB, acting like a serial communications device. Thanks to the device’s automatic calibration, it works with a variety of paper materials. As for reading speed, it’s pretty much only limited to how fast one can pull tape through without damaging it.

Stacked 1.6 mm PCBs act as an enclosure, of sorts.

While [Jürgen]’s device uses LEDs and phototransistors to detect the presence or absence of punched holes, it doesn’t rely on hardware calibration. Instead, the device takes analog readings of each phototransistor, and uses software-adjusted thresholds to differentiate ones from zeros. This allows it to easily deal with a wide variety of tape types and colors, even working with translucent materials. Reading 500 characters per second isn’t a problem if the device has had a chance to calibrate.

Interested in making your own? The build section of the project has all the design files; it uses only through-hole components, and since the device is constructed from a stack of 1.6 mm thick PCBs, there’s no separate enclosure needed.

Paper tape and readers have a certain charm to them. Cyphercon 4.0 badges featured tape readers, and we’ve even seen the unusual approach of encoding an I²C byte stream directly onto tape.