Retrocomputing

1433 Articles

Supersized Calculator Brings The Whole Intel 4004 Gang Together

November 16, 2025 by 23 Comments

Though mobile devices and Apple Silicon have seen ARM-64 explode across the world, there’s still decent odds you’re reading this on a device with an x86 processor — the direct descendant of the world’s first civilian microprocessor, the Intel 4004. The 4004 wasn’t much good on its own, however, which is why [Klaus Scheffler] and [Lajos Kintli] have produced super-sized discrete chips of the 4001 ROM, 4002 RAM, and 4003 shift register to replicate a 1970s calculator at 10x the size and double the speed, all in time for the 4004’s 50th anniversary.

We featured this project a couple of years back, when it was just a lonely microprocessor. Adding the other MSC-4 series chips enabled the pair to faithfully reproduce the logic of a Busicom 141-PF calculator, the very first to market with Intel’s now-legendary microprocessor. Indeed, this calculator is the raison d’etre for the 4004: Busicom commissioned the whole Micro-Computer System 4-bit (MCS-4) set of chips specifically for this calculator. Only later, once they realized what they had made, did Intel buy the rights back from the Japanese calculator company, and the rest, as they say, is history.

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The Fastest (68k) Macintosh Might Not Be An Amiga Anymore

November 15, 2025 by 19 Comments

Amiga and Atari fans used to lord over their Apple-eating brethren the fact that Cupertino never moved to the most advanced 68k processors — so for a while, thanks to 68060 accelerator cards, the fastest thing running Macintosh software was an Amiga (or Atari). After all these years, the Macintosh community is finally getting the last laugh, as [zigzagjoe] demonstrates an actual Macintosh booting with a 68060 CPU for the first time in a thread on 68KMLA. Video or it didn’t happen? Check it out below.

The Mac in question is a Quadra 650, which is a good choice since it was about the last thing Apple sold before switching to PowerPC, and ran the 68040 processor. [Reinauer] had already produced a 68040-to-68060 socket adapter (the two chips not being pinout compatible), so the hardware part of the battle was already set. Software, however? That was a different story, and where [zigzagjoe] put in the effort.

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2025 Component Abuse Challenge: The VIA Makes Noise, Again

November 14, 2025 by 3 Comments

In the days of 8-bit home computing, the more fancy machines had sound chips containing complete synthesizers, while budget machines made do with simple output ports connected to a speaker — if they had anything at all. [Normal User] appears to be chasing the later route, making PCM sound by abusing the serial port on a 6522 VIA chip.

A serial port is when you think about it, a special case of a one-bit output port. It’s designed for byte data communication but it can also carry a PCM data stream. We’ve seen this used with microcontrollers and peripherals such as the I2S port plenty of times here at Hackaday, to produce such things as NTSC video. The 1970s-spec equivalent might not be as fast as its modern equivalent, but it’s capable of delivering audio at some level. The machine in question is a Ben Eater breadboard 6502 with a World’s Worst Video Card, and as you can hear in the video below the break, it’s not doing a bad job for the era,

If you think this hack sounds a little familiar then in a sense you’re right, because Ben Eater himself made noises with a 6522. However it differs from that in that he used the on-board timers instead. After all, the “V” in “VIA” stands for “versatile”.

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FPGA Brings Antique Processor To Life

November 14, 2025 by 12 Comments

For the retro gaming enthusiast, nothing beats original hardware. The feel of the controllers and the exact timing of the original, non-emulated software provide a certain experience that’s difficult or impossible to replicate otherwise. To that end, [bit-hack] wanted to play the original EGA, 16-color version of The Secret of Monkey Island in a way that faithfully recreated the original and came up with this FPGA-based PC with a real NEC V20 powering it all.

The early 90s-style build is based on a low-power version of the V20 called the V20HL which makes it much easier to interface with a modern 3.3 V FPGA compared to the original 5 V chip. It’s still an IBM XT compatible PC though, with the FPGA tying together the retro processor to a 1 MB RAM module, a micro SD slot that acts as a hard disk drive, a digital-to-analog audio converter, and of course the PS/2 keyboard and mouse and VGA port. The mouse was one of the bigger challenges for [bit-hack] as original XT PCs of this era would have used a serial port instead.

With a custom PCB housed in a acrylic case, [bit-hack] has a modern looking recreation of an XT PC running an original processor and capable of using all of the period-correct peripherals that would have been used to play Monkey Island when it was first released.

FPGAs enable a ton of retrocomputing projects across a wide swath of platforms, and if you’re looking to get started the MiSTer FPGA project is a great resource.

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A photo of some drives with their controller boards

Installing An 84MB Hard Drive Into A PDP-11/44

November 12, 2025 by 8 Comments

Over on YouTube [Usagi Electric] shows us how he installed an 84MB hard drive into his PDP-11/44.

In the beginning he purchased a bunch of RA70 and RA72 drives and board sets but none of them worked. As there are no schematics it’s very difficult to figure out how they’re broken and how to troubleshoot them.

Fortunately his friend sent him an “unhealthy” Memorex 214 84MB hard drive, also known as a Fujitsu 2312. The best thing about this hard drive is that it comes complete with a 400 page manual which includes the full theory of operation and a full set of schematics. Score!

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Resurrecting Conquer: A Game From The 1980s

November 11, 2025 by 15 Comments

[Juan] describes himself as a software engineer, a lover of absurd humor, and, among other things, a player of Nethack. We think he should add computer game archaeologist to that list. In the 1990s, he played a game that had first appeared on USENET in 1987. Initially called “Middle-earth multiplayer game,” it was soon rebranded with the catchier moniker, Conquer.

It may not seem like a big thing today, but writing multiplayer software and distributing it widely was pretty rare stuff in the late 1980s or early 1990s. In 2006, [Juan] realized that this game, an intellectual predecessor to so many later games, was in danger of being lost forever. The source code was scattered around different archives, and it wasn’t clear what rights anyone had to the source code.

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An Unnecessary (But Cool) Processor

November 10, 2025 by 18 Comments

[Bob] calls his custom 16-bit computer “Bob’s Unnecessary Retro Processor” or BURP for short. While we suppose it is technically unnecessary, we love the look of it, and we hope he just used it to get the quirky acronym.

When we build custom CPUs they look suspiciously like FPGA development boards, but not BURP. We immediately thought of the IMSAI and the H8 when we saw it, but [Bob] points out it also borrows from the PDP-11.

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