A black device with a monochrome LCD sits on a wooden table. It's keyboard extends below the frame. On the screen is the "Level 29" BBS service login.

Internet Appliance To Portable Terminal

August 8, 2024 by Navarre Bartz 2 Comments

Few processors have found themselves in so many different devices as the venerable Z80. While it isn’t powerful by modern standards, you can still use devices like this Cidco MailStation as a terminal.

The MailStation was originally designed as an email machine for people who weren’t onboard with this whole computer fad, keeping things simple with just an adjustable monchrome LCD, a keyboard, and a few basic applications. [Joshua Stein] developed a terminal application, msTERM, for the MailStation thanks to work previously done on decoding this device and the wealth of documentation for Z80 assembly.

While [Stein] designed his program to access BBSes, we wonder if it might be a good way to do some distraction-free writing. If that wasn’t enough, he also designed the WiFiStation dongle which lets you communicate over a network without all that tedious mucking about with parallel ports.

If you’d like something designed specifically for writing, how about an AlphaSmart? Wanting to build your own Z80-based project? Why not start with an Altoids-sized Z80 SBC, but don’t wait forever since Z80 production finally ended in June.

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An odd looking apparatus for cleaning floppy disks. A neon green disk tray is suspended on metal linear rails in a vertical orientation. It can move back and forth through a set of cleaning heads and a set of drying fans. There are some control buttons on the font as well as a string of addressable LEDs and two speakers.

Rube Goldberg Floppy Disk Cleaner

August 2, 2024 by Navarre Bartz 6 Comments

Floppies were once the standard method of information exchange, but decades of storage can render them unreadable, especially if mold sets in. [Rob Smith] wanted to clean some floppies in style and made a Disco Rube Goldberg-Style device for the job.

Starting with a disk caddy on linear rails, [Smith] has a track for the floppy to follow. First it goes through a set of pads with cleaning solution on them, and is then dried off with heating elements. To make it more fun, the device has LEDs and a set of speakers at the bottom to treat the disk to a more complete car wash-esque experience.

Cotton swabs and a cleaning solution are all you really need to do the job by hand, but if you have a lot of floppies, that can get tedious quickly. [Smith] compares his machine’s performance to doing it by hand with both IPA and a dish soap solution showing that his machine does indeed clean the disks and usually makes them more readable than they were before. He cautions that it might be best to make multiple copies of the disk during the cleaning process as it isn’t always constructive though.

Thinking about archiving that stack of floppies under your workbench? While Linux doesn’t support the drives anymore, we’ve covered a couple different methods in the past and the importance of reading the flux.

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Tiny Tapeout 4: A PWM Clone Of Covox Speech Thing

June 21, 2024 by Dave Rowntree 4 Comments

Tiny Tapout is an interesting project, leveraging the power of cloud computing and collaborative purchasing to make the mysterious art of IC design more accessible for hardware hackers. [Yeo Kheng Meng] is one such hacker, and they have produced their very first custom IC for use with their retrocomputing efforts. As they lament, they left it a little late for the shuttle run submission deadline, so they came up with a very simple project with the equivalent behaviour of the Covox Speech Thing, which is just a basic R-2R ladder DAC hanging from a PC parallel port.

The computed gate-level routing of the ASIC layout

The plan was to capture an 8-bit input bus and compare it against a free-running counter. If the input value is larger than the counter, the output goes high; otherwise, it goes low. This produces a PWM waveform representing the input value. Following the digital output with an RC low-pass filter will generate an analogue representation. It’s all very simple stuff. A few details to contend with are specific to Tiny Tapout, such as taking note of the enable and global resets. These are passed down from the chip-level wrapper to indicate when your design has control of the physical IOs and is selected for operation. [Yeo] noticed that the GitHub post-synthesis simulation failed due to not taking note of the reset condition and initialising those pesky flip-flops.

After throwing the design down onto a Mimas A7 Artix 7 FPGA board for a quick test, data sent from a parallel port-connected PC popped out as a PWM waveform as expected, and some test audio could be played. Whilst it may be true that you don’t have to prototype on an FPGA, and some would argue that it’s a lot of extra effort for many cases, without a good quality graphical simulation and robust testbench, you’re practically working blind. And that’s not how working chips get made.

If you want to read into Tiny Tapeout some more, then we’ve a quick guide for that. Or, perhaps hear it direct from the team instead?

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Shipping Your Illicit Software On Launch Hardware

June 13, 2024 by Navarre Bartz 17 Comments

In the course of a career, you may run up against projects that get cancelled, especially those that are interesting, but deemed unprofitable in the eyes of the corporate overlords. Most people would move, but [Ron Avitzur] just couldn’t let it go.

In 1993, in the midst of the transition to PowerPC, [Avitzur]’s employer let him go as the project they were contracted to perform for Apple was canceled. He had been working on a graphing calculator to show off the capabilities of the new system. Finding his badge still allowed him access to the building, he “just kept showing up.”

[Avitzur] continued working until Apple Facilities caught onto his use of an abandoned office with another former contractor, [Greg Robbins], and their badges were removed from the system. Not the type to give up, they tailgated other engineers into the building to a different empty office to continue their work. (If you’ve read Kevin Mitnick‘s Ghost in the Wires, you’ll remember this is one of the most effective ways to gain unauthorized access to a building.)

We’ll let [Avitzur] tell you the rest, but suffice it to say, this story has a number of twists and turns to it. We suspect it certainly isn’t the typical way a piece of software gets included on the device from the factory.

Looking for more computing history? How about a short documentary on the Aiken computers, or a Hack Chat on how to preserve that history?

[Thanks to Stephen for the tip via the Retrocomputing Forum!]

Making Intel Mad, Retrocomputing Edition

June 9, 2024 by Bryan Cockfield 20 Comments

Intel has had a deathgrip on the PC world since the standardization around the software and hardware available on IBM boxes in the 90s. And if you think you’re free of them because you have an AMD chip, that’s just Intel’s instruction set with a different badge on the silicon. At least AMD licenses it, though — in the 80s there was another game in town that didn’t exactly ask for permission before implementing, and improving upon, the Intel chips available at the time.

The NEC V20 CPU was a chip that was a drop-in replacement for the Intel 8088 and made some performance improvements to it as well. Even though the 186 and 286 were available at the time of its release, this was an era before planned obsolescence as a business model was king so there were plenty of 8088 systems still working and relevant that could take advantage of this upgrade. In fact, the V20 was able to implement some of the improved instructions from these more modern chips. And this wasn’t an expensive upgrade either, with kits starting around $16 at the time which is about $50 today, adjusting for inflation.

This deep dive into the V20 isn’t limited to a history lesson and technological discussion, though. There’s also a project based on Arduino which makes use of the 8088 with some upgrades to support the NEC V20 and a test suite for a V20 emulator as well.

If you had an original IBM with one of these chips, though, things weren’t all smooth sailing for this straightforward upgrade at the time. A years-long legal battle ensued over the contents of the V20 microcode and whether or not it constituted copyright infringement. Intel was able to drag the process out long enough that by the time the lawsuit settled, the chips were relatively obsolete, leaving the NEC V20 to sit firmly in retrocomputing (and legal) history.

A System Board For The 8008

May 27, 2024 by Bryan Cockfield 27 Comments

Intel processors, at least for PCs, are ubiquitous and have been for decades. Even beyond the chips specifically built by Intel, other companies have used their instruction set to build chips, including AMD and VIA, for nearly as long. They’re so common the shorthand “x86” is used for most of these processors, after Intel’s convention of naming their processors with an “-86” suffix since the 1970s. Not all of their processors share this convention, though, but you’ll have to go even further back in time to find one. [Mark] has brought one into the modern age and is showing off his system board for this 8008 processor.

The 8008 predates any x86 processor by about six years and was among the first mass-produced 8-bit processors even before the well-known 8080. The expansion from four bits to eight was massive for the time and allowed a much wider range of applications for embedded systems and early personal computers. [Mark] goes into some of the details for programming these antique processors before demonstrating his system board. It gets power from a USB-C connection and uses a set of regulators and level shifters to make sure the voltages all match. Support for all the functions the 8008 needs is courtesy of an STM32. That includes the system memory.

For those looking to develop something like this, [Mark] has also added his development tools to a separate GitHub page. Although it’s always a good idea for those interested in computer science to take a look at old processors like these, it’s not always the easiest path to get original hardware like this, which also carries the risk of letting smoke out of delicate components. A much easier route is to spin up an emulator like an 8086 IBM PC emulator on an ESP32. Want to see inside this old chip? Have a look.

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Console Calculator Moves One Step Closer To Original Design

May 24, 2024 by Dan Maloney 14 Comments

With smartphone apps and spreadsheets being the main ways people crunch their numbers nowadays, there’s not much call for a desktop calculator. Or any other physical calculator, for that matter. Which is all the more reason to appreciate this Wang 300-series calculator console’s revival through a new electronic backend.

If you haven’t made the acquaintance of the Wang calculator series, [Bob Alexander]’s previous Wang project is a perfect introduction. Despite looking very much like an overbuilt early-70s desktop calculator, what you see in the video below is just a terminal, one of four that could connect to a shared “Electronics Package” where most of the actual computational work was done. The package was big and is currently hard to come by, at least at a reasonable price, but the consoles, with their Nixie displays and sturdy keypads, are relatively abundant.

[Bob]’s previous venture into reviving his console involved embedding a PIC32-based controller, turning it into the standalone desktop calculator it never was. To keep more with the original design philosophy, [Bob]’s second stab at the problem moves much of the same circuitry from inside the console into a dedicated outboard package, albeit one much smaller than the original. The replacement package extends and enhances the console functionality a bit, adding a real-time clock and a Nixie exercise routine to ward off the dreaded cathode poisoning. [Bob] also recreates the original Wang logarithmic method of multiplication and division, which is a nice touch with its distinctive flashing display.

Seeing the Wang console hooked up to a package through that thick cable and Centronics connector is oddly satisfying. We’d love to see [Bob] take this to the logical extent and support multiple consoles, but that might be pushing things a bit.

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