Retrocomputing

1495 Articles

ATABoy Is An Open Source USB Bridge For Old IDE Drives

February 23, 2026 by 27 Comments

You can get an IDE to USB bridge from all the usual sources, but you may find those fail on the older drives in your collection– apparently they require drives using logical block addressing, which did not become standard until the mid-1990s. Some while some older drives got in on the LBA game early, you were more likely to see Cylinder-Head-Sector (CHS) addressing. That’s why [JJ Dasher], a.k.a [redruM0381] created ATABoy, an open-source IDE bridge that can handle the oldest drives that fit on the bus.

The heart of the build is an RP2350, which serves as both IDE and USB host controller. To computer, after a little bit of setup, the drive attached to ATABoy shows up as a regular USB mass storage device. A little bit of setup is to be expected with drives of this vintage, you may remember. Luckily [JJ] included a handy BIOS-themed configuration utility that can be accessed through any serial console. He says you’ll usually be able to get away with “Auto Detect & Set Geometry,” but if you need to plug in the CHS values yourself, well, it’ll feel just like old times. Seeing is believing, so check it out in the demo video embedded below.

Though the custom PCB has a USB-C connector, and the USB-C standard could provide enough power for ye olde spinning rust drives, [JJ] didn’t include any power delivery with ATABoy. If you’re using it with a desktop, you can use the PSU in the box; MOLEX hasn’t changed. If you’re on a laptop, you’ll need another power supply– perhaps this USB-C powered benchtop unit.

If you’re using a Raspberry Pi or similar SBC, go ahead and skip USB entirely–the GIPO can do PATA IDE. Continue reading “ATABoy Is An Open Source USB Bridge For Old IDE Drives” →

How The Intel 8087 FPU Knows Which Instructions To Execute

February 21, 2026 by 4 Comments

An interesting detail about the Intel 8087 floating point processor (FPU) is that it’s a co-processor that shares a bus with the 8086 or 8088 CPU and system memory, which means that somehow both the CPU and FPU need to know which instructions are intended for the FPU. Key to this are eight so-called ESCAPE opcodes that are assigned to the co-processor, as explained in a recent article by [Ken Shirriff].

The 8087 thus waits to see whether it sees these opcodes, but since it doesn’t have access to the CPU’s registers, sharing data has to occur via system memory. The address for this is calculated by the CPU and read from by the CPU, with this address registered by the FPU and stores for later use in its BIU register. From there the instruction can be fully decoded and executed.

This decoding is mostly done by the microcode engine, with conditional instructions like cos featuring circuitry that sprawls all over the IC. Explained in the article is how the microcode engine even knows how to begin this decoding process, considering the complexity of these instructions. The biggest limitation at the time was that even a 2 kB ROM was already quite large, which resulted in the 8087 using only 22 microcode entry points, using a combination of logic gates and PLAs to fully implement the entire ROM.

Only some instructions are directly implemented in hardware at the bus interface (BIU), which means that a lot depends on this microcode engine and the ROM for things to work half-way efficiently. This need to solve problems like e.g. fetching constants resulted in a similarly complex-but-transistor-saving approach for such cases.

Even if the 8087 architecture is convoluted and the ISA not well-regarded today, you absolutely have to respect the sheer engineering skills and out-of-the-box thinking of the 8087 project’s engineers.

Retrotechtacular: Bleeding-Edge Memory Devices Of 1959

February 21, 2026 by 6 Comments

Although digital computers are – much like their human computer counterparts – about performing calculations, another crucial element is that of memory. After all, you need to fetch values from somewhere and store them afterwards. Sometimes values need to be stored for long periods of time, making memory one of the most important elements, yet also one of the most difficult ones. Back in the 1950s the storage options were especially limited, with a 1959 Bell Labs film reel that [Connections Museum] digitized running through the bleeding edge of 1950s storage technology.

After running through the basics of binary representation and the difference between sequential and random access methods, we’re first taking a look at punch cards, which can be read at a blistering 200 cards/minute, before moving onto punched tape, which comes in a variety of shapes to fit different applications.

Electromechanical storage in the form of relays are popular in e.g. telephone exchanges, as they’re very fast. These use two-out-of-five code to represent the phone numbers and corresponding five relay packs, allowing the crossbar switch to be properly configured.

Continue reading “Retrotechtacular: Bleeding-Edge Memory Devices Of 1959” →

An image of a magnetically-suspended Lemming

Mag-Lev Lemming Refuses To Fall

February 19, 2026 by 11 Comments

Are you ready to feel old? Lemmings just turned thirty-five. The famous puzzle game first came out in February of 1991 for the Commodore Amiga, before eventually being ported to just about everything else out there, from the ZX Spectrum to the FM Towns, and other systems so obscure they don’t have the class to start with two letters, like Macintosh and DOS. [RobSmithDev] decided he needed to commemorate the anniversary with a real floating lemming.

The umbrella-equipped lemming is certainly an iconic aspect of the game franchise, so it’s a good pick for a diorama. Some people would have just bought a figurine and hung it with some string, but that’s not going to get your project on Hackaday. [Rob] designed and 3D printed the whole tableau himself, and designed magnetic levitation system with some lemmings-themed effects.

The mag-lev is of the top-down type, where a magnet in the top of the umbrella is pulled against gravity by an electromagnetic coil. There are kits for this sort of thing, but they didn’t quite work for [Rob] so he rolled his own with an Arduino Nano. That allowed him to include luxuries you don’t always get from AliExpress like a thermal sensors.

Our favorite part of the build, though, has to be the sound effects. When the hall effect sensor detects the lemming statue — or, rather, the magnet in its umbrella — it plays the iconic “Let’s Go!” followed by the game’s sound track. If the figurine falls, or when you remove it, you get the “splat” sound, and if the lemming hits the magnet, it screams. [Rob] posted a demo video if you just want to see it in action, but there’s also a full build video that we’ve embedded below.

A commemorative mag-lev seems to be a theme for [Rob] — we featured his 40th anniversary Amiga lamp last year, but that’s hardly all he gets up to. We have also seen functional replicas, this one of a motion tracker from Aliens, and retrotech deep-dives like when he analyzed the magical-seeming tri-format floppy disk.

Continue reading “Mag-Lev Lemming Refuses To Fall” →

6502 based laptop

Retro Rover: LT6502 Laptop Packs 8-Bit Power On The Go

February 17, 2026 by 9 Comments

Making your own laptop can be a challenging project, but a doable one, especially given the large number of options available today for computing. Of course nothing says you need to use a modern component in your build, and in the LT6502 project by [TechPaula] they didn’t go with a modern RPi or the like, nope went right back to about 50 years ago to use a 6502 at the heart of this DIY laptop build.

The 6502 is an 8-bit microprocessor from the 1970s, found in the Commodore 64 and Apple II. This wasn’t their first venture into 8 MHz world of the 6502, prior to this laptop build there was a desktop build the PC6502 bringing this chip of old into a PC/104 form factor. The LT6502 adds in the things you’d expect with a laptop, a 9-inch foldable screen, a 10,000 mAh battery, several external ports for things such as serial console and USB-C charging. A custom keyboard adds in low-profile switches as well as including a HDSP-style 8-character display, a great addition for a modern take on this vintage chip. Onboard there is 46 KB of RAM and with the addition of the CompactFlash for storage the LT6502 runs EhBASIC which we’ve seen before in some other great projects.

The case is mainly 3D-printed safely enclosing the custom PCBs for both the keyboard and motherboard, and providing a satisfying glow with the built-in LEDs within. All of the files are up on the project’s site so be sure to swing by and check out both this and the desktop PC/104 predecessor to it. Great job [TechPaula], looking forward to seeing the future installments on the LT6502 such as implementing the included internal expansion slot.

Software Development On The Nintendo Famicom In Family BASIC

February 15, 2026 by 9 Comments

Back in the 1980s, your options for writing your own code and games were rather more limited than today. This also mostly depended on what home computer you could get your hands on, which was a market that — at least in Japan — Nintendo was very happy to slide into with their ‘Nintendo Family Computer’, or ‘Famicom’ for short. With the available peripherals, including a tape deck and keyboard, you could actually create a fairly decent home computer, as demonstrated by [Throaty Mumbo] in a recent video.

Continue reading “Software Development On The Nintendo Famicom In Family BASIC” →

Vintage Canadian Video Hardware Becomes Homebrew Computer

February 14, 2026 by 7 Comments

Are you in the mood for a retrocomputing deep dive into the Scriptovision Super Micro Script? It was a Canadian-made vintage video titler from the 80s, and [Cameron Kaiser] has written up a journey of repair and reverse-engineering for it. But his work is far more than just a refurbish job; [Cameron] transforms the device into something not unlike 8-bit homebrew computers of the era, able to upload and run custom programs with a limited blister keypad for input, and displaying output on a composite video monitor.

Continue reading “Vintage Canadian Video Hardware Becomes Homebrew Computer” →