Reconstructing Data From A Corrupt Apple ][ Floppy Disk

January 27, 2021 by Maya Posch 47 Comments

Back in 1990 [Benjamin Zotto] wrote – while in elementary school – a dog racing game called Wonderland 2. The BASIC source code and images for the game were stored on a single ProDOS formatted, soft-sectored 5.25″ floppy disk. Fast-forward thirty years to today and [Benjamin] found to his dismay that ProDOS could no longer read the floppy, giving an I/O error. Not deterred, he set about to recover the data, as documented in this Twitter thread.

Applesauce visualization of the patterns on the corrupted disk, with soft-sectoring spiral arms.

The gist of the story is that the floppy disk’s surface could still be scanned with help from the aptly named Applesauce Floppy Drive Controller, which got the following visualization of the magnetic patterns on the disk surface:

This data could then be analyzed sector by sector, with the bad sectors and the cause for ProDOS flaking out with its reading attempts here marked in red.

Checking the data recovered so far confirmed that it was a ProDOS disk. It also confirmed that the sector containing the directory listing was shot. This required diving into the technical reference manual for ProDOS and its filesystem to figure out how to reconstruct the directory layout. This required figuring out the offsets and sizes of the files, assisted by knowing what was likely on the disk, and having some bits and pieces of the original volume listing still intact. This allowed for the directory volume to be rebuilt, one byte at a time.

Sectors on the disk, with bad sectors in red.

At the end of that arduous and highly educational journey success waited, and [Benjamin] was once again able to relive his memories of 1990s BASIC and hand-drawn bitmap graphics.

Homebrew Relay Computer Looks Like It Could Be A Commercial Product

January 19, 2021 by Dan Maloney 21 Comments

You may not have noticed, but we here at Hackaday really love our clicky stuff. Clicky mechanical keyboards, unnecessarily noisy flip-dot displays, and pretty much anything made with a lot of relays — they all grab our attention, in more ways than one. So it’s with no small surprise that we appear to have entirely missed perhaps the clickiest build of all: a fully operational 8-bit computer using nothing but relays.

What’s even more amazing about our failure to find and feature [Paul Law]’s excellent work is that he has been at it for the better part of a decade now. The first post on his very detailed and very well-crafted blog describing the build dates from 2013, when he was just testing LEDs in the arithmetic-logic unit (ALU). Since then, [Paul] has made incredible progress, building module after module, each containing a small portion of the computer’s functionality. The modules plug into card cages with backplanes to connect them, and the whole thing lives in an enclosure made from aluminum extrusion and glossy black panels for a truly sleek look. The computer is incredibly compact for something that uses 400+ DPDT relays to do its thinking.

In addition to the blog, [Paul] has a criminally undersubscribed YouTube channel with a quite recent series going over the computer in depth. We included the overall tour below, but you should really check out the rest of the videos to appreciate how much work went into this build. We’ve seen relay computers ranging in size from single-board to just plain ludicrous, but this one really takes the prize for fit and finish as well as functionality.

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TRS-80 Model 100 Gets 64-Bit CPU And A Very Wide LCD

January 17, 2021 by Tom Nardi 32 Comments

To say the TRS-80 Model 100 was ahead of its time would be something of an understatement. It had a high-quality mechanical keyboard, phenomenal battery life, plenty of I/O and expansion capabilities, and was actually small and light enough to easily carry around. While its layout might seem to be a bit dated to modern eyes, there’s little debate that it was one of the most successful and influential computers in history.

So it’s little surprise that [belsamber] thought the Model 100 might make an ideal platform for his mobile command line work. With a few modifications, naturally. While technically the nearly 40 year old portable could connect to a Linux computer as a simple serial terminal, its outdated and non-backlit LCD leaves a bit to be desired in 2021. But there’s little sense in upgrading the display if he’d still be saddled with the anemic Intel 80C85 motherboard, so he decided to clean house and replace everything.

Once stripped of the original hardware, the Model 100’s enclosure offered up plenty of room for a Pine A64 LTS single-board computer, four 18650 cells, and a 1920×480 ultra-wide LCD. While not a perfect match for the dimensions of the original panel, the new screen is an exceptionally close fit. The keyboard has been left intact, but rather than adding a QMK-compatible microcontroller to the mix, [belsamber] wired the matrix directly into the GPIO of the A64.

While we know some retro aficionados might shed a tear to see an iconic computer get gutted, [belsamber] mentions that nothing will go to waste; the parts he pulled from this machine will serve as spares for a second Model 100 he has in his collection. Besides, given the immense popularity of these machines, they aren’t exactly rare to begin with.

As an aside, we recently saw this same unique display used in a 3D printed desktop computer with distinctively retro-futuristic styling. We didn’t have miniature 4:1 ratio displays on our list of 2021 hardware predictions, but it seems they’re already making a strong showing.

RISC-V Comes To The BeagleBoard Ecosystem With Upcoming Beagle V SBC

January 14, 2021 by Jenny List 54 Comments

The Beagle V, a RISC-V-based single board computer from a collaboration between BeagleBoard and Seeed Studios aims to be “The First Affordable RISC-V Computer Designed to Run Linux”. RISC-V is the open-source processor architecture that everyone is interested in because it bypasses proprietary silicon of manufacturers such as Intel or AMD, allowing companies to roll their own silicon processors without licensing fees for the core.

BeagleBoard has long been one of the major players in the Single-Board Computer arena so far dominated by the Raspberry Pi. The board, slightly larger than the company’s previous offerings, features a StarFive dual-core 64-bit RISC-V processor running at a 1.0 GHz clock speed. The spec sheet on their GitHub repo indicates 4 and 8 GB RAM options, built-in WiFi and Bluetooth, and hardware video support for decoding, two camera connectors, one DSI connector for an external display, as well as a full-sized HDMI port. Gigabit Ethernet, four USB-3 ports, an audio jack, and USB-C as the power supply are packed onto the edges of the board. GPIO is routed to a 2×20 pin header.

Seeed Studio pegs the cost of the board at $149 for the 8 GB RAM version, although currently you must apply and be selected to purchase a board in this early stage. It’s unclear if the price will remain unchanged after this first run; the product page notes a coupon code is necessary and the Seeed Studios article indicates this is an introductory price. However, the same article also lists the 4 GB RAM variant at $119. The BeagleBoard page shows a timeline of April 2021 for a “pilot run for community”.

It’s exciting to see RISC-V continue to make inroads. This is a powerful board based around the core, and if successful it will help further prove the viability of open source processing cores in increasingly mainstream products.

Making A Kid-Friendly Computer As A Present: Or How To Be The Cool Aunt At Christmas

January 13, 2021 by Erin Pinheiro 24 Comments

This article was meant to be finished up before Christmas, so it’ll be a little late whenever you’re reading it to go and prepare this for the holiday. Regardless, if, like me, should you ever be on the lookout for something to give a toddler nephew or relative, it could be worth it to look into your neglected old parts shelves. In my case, what caught my eye was a 9-year-old AMD laptop catching dust that could be better repurposed in the tiny hands of a kid eager to play video games.

The main issues here are finding a decent selection of appropriate games and streamling the whole experience so that it’s easy to use for a not-yet-hacker, all the while keeping the system secure and child-friendly. And doing it all on a budget.

This is a tall order, and requirements will be as individual as children are, of course, but I hope that my experience and considerations will help guide you if you’re in a similar boat.

Continue reading “Making A Kid-Friendly Computer As A Present: Or How To Be The Cool Aunt At Christmas” →

NVMe Blurs The Lines Between Memory And Storage

January 13, 2021 by Maya Posch 50 Comments

The history of storage devices is quite literally a race between the medium and the computing power as the bottleneck of preserving billions of ones and zeros stands in the way of computing nirvana. The most recent player is the Non-Volatile Memory Express (NVMe), something of a hybrid of what has come before.

The first generations of home computers used floppy disk and compact cassette-based storage, but gradually, larger and faster storage became important as personal computers grew in capabilities. By the 1990s hard drive-based storage had become commonplace, allowing many megabytes and ultimately gigabytes of data to be stored. This would drive up the need for a faster link between storage and the rest of the system, which up to that point had largely used the ATA interface in Programmed Input-Output (PIO) mode.

This led to the use of DMA-based transfers (UDMA interface, also called Ultra ATA and Parallel ATA), along with DMA-based SCSI interfaces over on the Apple and mostly server side of the computer fence. Ultimately Parallel ATA became Serial ATA (SATA) and Parallel SCSI became Serial Attached SCSI (SAS), with SATA being used primarily in laptops and desktop systems until the arrival of NVMe along with solid-state storage.

All of these interfaces were designed to keep up with the attached storage devices, yet NVMe is a bit of an odd duck considering the way it is integrated in the system. NVMe is also different for not being bound to a single interface or connector, which can be confusing. Who can keep M.2 and U.2 apart, let alone which protocol the interface speaks, be it SATA or NVMe?

Let’s take an in-depth look at the wonderful and wacky world of NVMe, shall we?

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3D Printed Pi Laptop Honors The Iconic GRiD Compass

January 11, 2021 by Tom Nardi 28 Comments

If you’re familiar with vintage portable computers, you know about the GRiD Compass. Even if you’re not into computers of yesteryear, there’s a good chance you’ve seen a Compass or two without realizing it. From battling xenomorphs in Aliens to making the trip to orbit aboard the Space Shuttle, the trendsetting clamshell computer seemed to be everywhere in the 1980s. While far too expensive for the average consumer to afford back then, its no-compromise design and sleek looks helped lay the groundwork for today’s ubiquitous laptops.

Getting your hands on a working GRiD Compass in 2021 isn’t a whole lot easier than it was in 1982, so [Mike] decided to do the next best thing and build his own. His GRIZ Sextant certainly isn’t a replica, but the family resemblance is strong enough to get the point across. The Raspberry Pi powered machine has a greatly reduced “trunk” section in the back as you might expect, but the overall layout is very similar. The Commodore 64 inspired color scheme is probably the biggest departure from the source material, but it’s hard to argue with the results.

It’s clear at a glance that a lot of thought was put into the external aesthetics of the Sextant, but a peek under the hood shows the internal details are equally impressive. [Mike] tells us he has a background in product design, and it shows. Rather than approaching this project as a one-off creation, he’s clearly taken great pains to ensure the design is as reproducible as possible.

All of the individual components of the 3D printed frame and enclosure have been carefully designed so they’ll fit within the build volume of the average desktop machine. Electronic components are screwed, not glued, to the internal framework; making future repairs and maintenance much easier. When combined with the ample internal volume available, this modular approach should make adding custom hardware a relatively painless process as well.

So when will you be able to build a GRIZ Sextant of your own? Hopefully, very soon. [Mike] says he still needs to work some kinks out of the power supply and finalize how the speakers will get mounted into the case. Once those last tweaks are locked in, he plans to release all the STL files and a complete Bill of Materials. For those who want to get a sneak peek before they start warming up the extruder, he’s also started documenting the assembly of the Sextant on his YouTube channel. Continue reading “3D Printed Pi Laptop Honors The Iconic GRiD Compass” →