PC-XT Emulator On ESP8266

Do you remember the simpler times when you had a DOS command line, a handful of commands, and you talked to the hardware through a few BIOS and DOS interrupts? Okay, maybe it was a little limited, but nostalgia doesn’t care. Now [mcuhacker] is working on bringing some of those memories back by getting a PC-XT emulator running on an ESP8266.

For the x86 CPU emulator, he ported Fake86 which is written in C, and created an Arduino IDE environment for it. The MS-DOS 3.3 bootdisk image is stored in flash and is accessed as the A: drive. There’s no keyboard yet but he has 640×200 CGA working with 80×25 characters on a 3.5″ TFT display with the help of a low pass filter circuit. In the video below he shows it booting to the point where it asks for the date.

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The IBM PC That Broke IBM

It was the dawn of the personal computer age, a time when Apple IIs, Tandy TRS-80s, Commodore PETs, the Atari 400 and 800, and others had made significant inroads into schools and people’s homes. But IBM, whose name was synonymous with computers, was nowhere to be seen. And yet within a few years, the IBM PC would be the dominant player.

Those of us who were around at the time cherished one of those early non-IBM computers, and as the IBM PC came out, either respected it, looked down on it, or did both. But now, unless your desktop machine is a Mac, you probably own a computer that owes its basic design to the first IBM PC.

The Slow Moving Elephant

IBM System/360 Model 30 mainframe
IBM System/360 Model 30 mainframe by Dave Ross CC BY 2.0

In the 1960s and 1970s, the room-filling mainframe was the leading computing platform and the IBM System/360 held a strong position in that field. But sales in 1979 in the personal computer market were $150 million and were projected to increase 40% in 1980. That was enough for IBM to take notice. And they’d have to come up with something fast.

Fast, however, wasn’t something people felt IBM could do. Decisions were made through committees, resulting in such a slow decision process that one employee observed, “that it would take at least nine months to ship an empty box.” And one analyst famously said, “IBM bringing out a personal computer would be like teaching an elephant to tap dance.”

And yet, in just a few short years, IBM PCs dominated the personal computer market and the majority of today’s desktops can trace their design back to the first IBM PC. With even more built-in barriers which we cover below, how did the slow-moving elephant make this happen?

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The Oldest Known Surviving PC Operating System

You’ll all be familiar with the PC, the ubiquitous x86-powered workhorse of desktop and portable computing. All modern PCs are descendants of the original from IBM, the model 5150 which made its debut in August 1981. This 8088-CPU-driven machine was expensive and arguably not as accomplished as its competitors, yet became an instant commercial success.

The genesis of its principal operating system is famous in providing the foundation of Microsoft’s huge success. They had bought Seattle Computer Products’ 86-DOS, which they then fashioned into the first release version of IBM’s PC-DOS. And for those interested in these early PC operating systems there is a new insight to be found, in the form of a pre-release version of PC-DOS 1.0 that has found its way into the hands of OS/2 Museum.

Sadly they don’t show us the diskette itself, but we are told it is the single-sided 160K 5.25″ variety that would have been the standard on these early PCs. We say “the standard” rather than “standard” because a floppy drive was an optional extra on a 5150, the most basic model would have used cassette tape as a storage medium.

The disk is bootable, and indeed we can all have a play with its contents due to the magic of emulation. The dates on the files reveal a date of June 1981, so this is definitely a pre-release version and several months older than the previous oldest known PC-DOS version. They detail an array of differences between this disk and the DOS we might recognise, perhaps the most surprising of which is that even at this late stage it lacks support for .EXE executables.

You will probably never choose to run this DOS version on your PC, but it is an extremely interesting and important missing link between surviving 86-DOS and PC-DOS versions. It also has the interesting feature of being the oldest so-far-found operating system created specifically for the PC.

If you are interested in early PC hardware, take a look at this project using an AVR processor to emulate a PC’s 8088.

Header image: (CC BY-SA 3.0 DE).

Boy Off The Grid For Years Writes GUI for DOS

In a hacker version of Jumanji, when [fiberbundle]’s parents divorced, his thrice-fugitive new stepfather took him to a remote location in Australia without any access to technology or the outside world. With him he brought an old 486, a gift from his real dad. Lest the police discover them, [fiberbundle] was forbidden contact from most of society and even restricted in the books he was allowed to read.

The boy spent years trying to get the most he could out of his two-generations-old PC. Using only two textbooks from a decade and a half earlier, DOS 6.0, and QBasic he managed to write his own shell dubbed OSCI (pronounced “Aussie”), a ray-caster 3d engine and lots more. No mentors, no Internet. The computers at school were even more outdated Power Macs.

Eventually life returned him to civilization to be mindblown by modern technology 1000x as powerful. He went from playing text-based adventures he had to write for himself, to seeing Crysis. From QBasic to C++. From ASCII art “shooters” to Half-Life 2. From a 486 to a 4-core CPU. From a rural library to Wikipedia.

Follow the link above to see screens of his projects over the years. As of yet no one has verified the story, but, even if only that it is worth a read.

Thanks [Gustavo] for the tip.

THP Hacker Bio: David Cook


[David Cook] has been on the front page with gnarly hacks many times. We’re happy to present his Hackaday Projects profile as this week’s Hacker Bio.

His entry for The Hackaday Prize is something of a one-wireless-pair-to-rule-them approach to connected devices which he calls LoFi. We were delighted by his first demo video which is exactly what we envisioned for preliminary entries; [David] explains the concept and how he plans to implement it using a few visual aids to drive the point home.

Join us after the break to find out more about [David]. Oh, if you’re wondering about the times he’s been featured on Hackaday, check out his capacitor/coin cell swap which is one of our favorites.

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Hackaday Links: January 26, 2014


The automotive industry is rolling more and more tech into their offerings. This is great for us because replacement or salvaged parts are great for projects. Here’s one component to look for. [MikesElectricStuff] tears apart the thermal imaging camera form an Audi. [via Hacked Gadgets]

Give your valentine an analog love note on the big day. [Tom’s] LED heart chaser design does it without any coding. It’s a 555 timer with CD4017 decade counter. The nice thing about the setup is a trimpot adjusts the chaser speed.

[Jan] is overclocking his Arduino to 32 MHz. For us that’s kind of an “eh” sort of thing. But his statement that you need to use a clock generator because the chip won’t work with an oscillator at that frequency raised an eyebrow. We saw an AVR chip running from a 32MHz crystal oscillator in the RetroWiz project from yesterday. So do we have it wrong or does [Jan]? Share your opinion in the comments.

Download a copy of the Apple II DOS source code… legally. Yay for releasing old code into the wild! The Computer History Museum has the DOS source code and a bunch of interesting history about it. [via Dangerous Prototypes]

While we were prowling around DP for the last link we came across [Ian’s] post on a new version of Bus Pirate cables. We’ve got the old rainbow cables which are pretty convenient. But if you’ve used them you’ll agree, hunting for the correct color for each connection isn’t anywhere near a fool-proof method. The new cable uses shrink tube printed with probe labels. They sound like a huge pain to manufacture. But this makes connections a lot easier. In our experience, when it doesn’t work its always a hardware problem! Hopefully this will mean fewer botched connections.

Make your tiny LiPo cells last longer. Not capacity wise, but physically. The delicate connections to the monitor PCB break easily, and the plug is really hard to connect and disconnect. [Sean] shows how he uses electrical tape for strain relief, and a bit of filing to loosen up the connector.

KerbalEdu: Kerbal Space Program for education. That’s right, you can play Kerbal as part of school now. Some may shake their heads at this, but school should be fun. And done right, we think gaming is a perfect way to educate. These initiatives must be the precursor to A Young Lady’s Illustrated Primer method of education. Right?

Repairing a mill that cost as much as a car


Years ago, someone at the bio-instrumentation lab at MIT needed to change a CMOS battery in the controller for a three axis mill. This reset the machine’s BIOS and was widely regarded as a bad move. The mill sat in the lab for a few years before  Prof. [Ian Hunter] donated it to MITERS – the student shop at MIT. And so the task of repairing a machine that cost as much as a car fell upon a plucky group of students.

The machine – a  Dyna-Myte 1007 has a 10″x7″x10″ work area, pneumatic tool changers and carousel, and the working for a fourth axis. It is. however, driven by an ancient Pentium computer running DOS with all the fun of ISA slots and IRQs that entails.

The MITERS began their repair by digging around in the software configuration, finding the axis drive is controlled via IRQ 3, which was currently occupied by COM 2. Changing that in the BIOS let the computer control the axes and, with a few solenoids and an air compressor, the tool carousel also worked.

With a bit of digging around, the MITERS also got the spindle working, giving them a very awesome and very expensive CNC milling machine for free. Even though the computer could be replaced with a $35 Raspberry Pi, we really have to admire the MITERS for fixing what they already had; it’s a cheaper and much, much faster way to get their new toy up and running.

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