Recovering Data From Floppies With Errors

June 3, 2019 by Jenny List 36 Comments

Those of us of advancing years will remember the era of the floppy disc. Maybe not that of the 8-inch drive, but probably its 5.25-inch and certainly its 3.5-inch cousins. Some will remember the floppy disc fondly, while for others there will be recollections of slow and unreliable media with inadequate capacity, whose ability to hold data for any length of time was severely questionable. Add three decades to the time a disc has spent in storage, and those data errors become frequent. The life of a retrocomputing enthusiast hoping to preserve aged software is made extremely difficult by them, and [Michael Steil] has a few tips to help with recovery.

It’s written with specific reference to Commodore 5.25-inch floppies, but aside from some of the specific software, the techniques could be applied to any discs. Most interesting is his explanation of the mechanisms that lead to bad discs or bad sectors, before he looks at some of the mitigations that might be employed. Cleaning the disc or the drive head with alcohol is explored, then taking a dump of the raw data for detailed inspection and disassembly in search of checksum errors. If in your youth a floppy disc was just something you put in a drive and you never investigated further, perhaps this piece will fill in some of the gaps.

If the thought of a stack of Commodore 64 floppies fills you with dread, how about using an emulator?

Header image: PrixeH [CC BY-SA 3.0].

This Commodore 16 Is An NTSC One… No, Wait, It’s A PAL One!

June 1, 2019 by Jenny List 7 Comments

We’re used to our computers being powerful enough in both peripheral and processing terms to be almost infinitely configurable under the control of software, but there was a time when that was not the case. The 8-bit generation of home computers were working towards the limits of their capability just to place an image on a TV screen, and every component would have been set up to do just the job it was intended for. Thus when different countries had different TV standards such as the mostly-European PAL and the mostly-American NTSC, there would have been different models of the same machine for each market. The Commodore 16 was just such a machine, and [Adrian Black] has modified his NTSC model with a custom ROM, an Arduino and an Si5351 clock generator to be switchable between the two.

The differences between a PAL and NTSC C16 are two-fold. The clock for the video chip is of a different frequency, and the ROM contents differ too. [Adrian]’s machine therefore has a larger ROM containing both versions which are switchable via one of the upper address lines. A couple of tracks cut in the crystal oscillator circuit allow him to inject a new clock from the Si5351 module, and and Arduino controls everything. The appropriate ROM and clock are selected via a very simple interface, the reset button is captured and while a short press still resets the computer a long one switches the mode.

Despite having its principal engineer, [Bil Herd] as a colleague here at Hackaday, it’s sad that we don’t see as many Commodore 16s as we should. A recent feature showed a 64k C16, but didn’t make it into a C64.

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AI-Enabled Teletype Live Streams Nearly Coherent Conversations

May 23, 2019 by Dan Maloney 17 Comments

If you’ve got a working Model 33 Teletype, every project starts to look like an excuse to use it. While the hammering, whirring symphony of a teleprinter going full tilt brings to mind a simpler time of room-sized computers and 300 baud connections, it turns out that a Teletype makes a decent AI conversationalist, within the limits of AI, of course.

The Teletype machine that [Hugh Pyle] used for this interesting project, a Model 33 ASR with the paper tape reader, is a nostalgia piece that figures prominently in many of his projects. As such, [Hugh] has access to tons of Teletype documentation, so when OpenAI released their GPT-2 text generation language model, he decided to use the docs as a training set for the model, and then use the Teletype to print out text generated by the model. Initial results were about as weird as you’d expect for something trained on technical docs from the 1960s. The next step was obvious: make a chat-bot out of it and stream the results live. The teletype can be seen clattering away in the recorded stream below, using the chat history as a prompt for generating text responses, sometimes coherent, sometimes disturbing, and sometimes just plain weird.

Alas, the chat-bot and stream are only active a couple of times a week, so you’ll have to wait a bit to try it out. But it looks like a fun project, and we appreciate the mash-up of retro tech and AI. We’ve seen teleprinters revived for modern use before, both for texting and Tweeting, but this one almost has a mind of its own.

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Zork And The Z-Machine: Bringing The Mainframe To 8-bit Home Computers

May 22, 2019 by Maya Posch 30 Comments

Computer games have been around about as long as computers have. And though it may be hard to believe, Zork, a text-based adventure game, was the Fortnite of its time. But Zork is more than that. For portability and size reasons, Zork itself is written in Zork Implementation Language (ZIL), makes heavy use of the brand-new concept of object-oriented programming, and runs on a virtual machine. All this back in 1979. They used every trick in the book to pack as much of the Underground Empire into computers that had only 32 kB of RAM. But more even more than a technological tour de force, Zork is an unmissable milestone in the history of computer gaming. But it didn’t spring up out of nowhere.

The computer revolution had just taken a fierce hold during the second World War, and showed no sign of subsiding during the 1950s and 1960s. More affordable computer systems were becoming available for purchase by businesses as well as universities. MIT’s Laboratory for Computer Science (LCS) was fortunate to have ties to ARPA, which gave MIT’s LCS and AI labs (formerly part of Project MAC) access to considerable computing resources, mostly in the form of DEC PDP systems.

The result: students at the MIT Dynamic Modeling Group (part of LCS) having access to a PDP-10 KA10 mainframe — heavy iron at the time. Though this PDP-10 was the original 1968 model with discrete transistor Flip Chip modules and wire-wrapping, it had been heavily modified, adding virtual memory and paging support to expand the original 1,152 kB of core memory. Running the MIT-developed Incompatible Timesharing System (ITS) OS, it was a highly capable multi-user system.

Naturally, it got mostly used for playing games.
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How Hard Can It Be To Buy A Computer In Germany And Get It Back Home To The UK?

May 21, 2019 by Jenny List 40 Comments

Some of the best adventures in the world of hardware hacking start in the pub. For three volunteers at the National Museum Of Computing in the UK, [Adam Bradley], [Chris Blackburn], and [Peter Vaughan], theirs started over a pint with an eBay listing for an old computer in Germany. No problem you might think, we’re well used to international parcel shipping. This computer wasn’t a crusty old Commodore 64 though, instead it was a room-sized IBM System/360 Model 20 from the 1960s, complete with the full array of peripherals and what seemed to be a lot of documentation and software media. It would need a Mercedes Sprinter, a large van, to shift it, but that seemed feasible. With a bit of frantic bidding they secured the auction, and set off for Germany to view their purchase.

Arriving at the machine’s location they found a little bit more than they had expected. In an abandoned building on a side street in Nuremburg there was an intact machine room full of the IBM computer cabinets over a false floor with all the machine cabling in place, and the only usable access was through a street door which hadn’t been opened in decades and which was obstructed by the false floor itself. To cap it all they found they’d bought not one but two System/360s, and also unexpectedly a 1970s System/370 Model 125. Clearly this was more than a job for a quick in-and-out with a Sprinter.

What followed became a lengthy saga of repeated trips, van hire, constructing ramps, and moving heavy computer parts to a hastily rented storage unit. Decabling a computer of this size is no easy task at the best of times, and these cables had spent many decades in a neglected machine room. It’s a fascinating read, and a very well-documented one with plenty of photos. The machines now sit in their storage units awaiting a return to the UK, and the trio are soliciting any help they can find to make that happen. So if you happen to own a European haulage company with spare capacity on your Germany — UK route or if you can help them in any way, donate or get in touch with them. We think this project has much more to offer, so we’ll be following their progress with interest.

These three intrepid computer hunters were brought together at The National Museum Of Computing at Bletchley, UK. If you find yourself within range it is an essential place to visit, we did so in 2016.

A Trash-Steam-Machine-80

May 18, 2019 by Jenny List 24 Comments

Sometimes for a retrocomputing enthusiast it can be challenging to see a surviving machine gutted and used for another purpose. But in the case of [Tom Pick]’s Radio Shack TRS-80 based Steam Machine PC we can forgive him, because it began with a very unpromising machine that had most definitely seen better days.

The TRS-80 in question is a Model III, the all-in-one console device with a numerical keypad, CRT monitor, and dual 5.25″ floppy drives built in. This provided plenty of space for the components of a modern PC with a 12″ LCD monitor. The PC itself is a run-of-the mill 2.6 GHz Pentium and nothing exceptional, but its input devices are of note. The keyboard is a Red Dragon mechanical item which has been made to look the part in place of the old Radio Shack item with a set of custom colour-coded keycaps, while the pointing device in a particularly neat touch is a modern Radio Shack-branded mouse. The boot screen is the proper Radio Shack logo from the TRS-80’s heyday, meaning that if you didn’t know any differently you might think this was meant to be. Sadly the two floppy drives are unconnected, though we’re sure it would be possible to make a modern PC see them for a bit of 360k storage goodness.

We don’t see as many projects featuring the TRS-80 series as we should, and the model III is a particular rarity. Far more common in these pages is the portable Model 100, most recently gaining a cellular connection.

Retrotechtacular: History Of Sony Mini Doc Bursts With 1970s Style

May 10, 2019 by Drew Littrell 16 Comments

The 1970s, it was a time when cameras needed film, phones had cords, and televisions masqueraded as furniture. A time where hi-fi systems were judged by the volume knob feel, and thanks to YouTube user [nefesh22] we have a behind-the-scenes glimpse of what the era was like from the Sony corporate perspective in this mini documentary of the company’s history below. The film was originally created for internal use at Sony’s US manufacturing facilities in San Diego, however, now it now can be watched by anyone with an internet connection.

Sony’s corporate ethos of allowing its engineers to drive business innovation is on full display here. For instance how in 1950 Sony introduced the first magnetic tape recorder, the G-Type, in Japan and followed that up with the first portable television, the TV8-301, a decade later. Throughout the 1970s Sony became an innovator in the video space. In fact, the Sony Trinitron brand of color TVs garnered so much notoriety in the television industry that the company was awarded an Emmy in 1973. Though the most telling feature is the documentary’s focus on the 3/4-inch U-Matic videocassette format, a precursor to VHS and Sony’s own Betamax videotapes. Highlighting the “superiority” of those VTR systems of the day really does date the film as those hulking decks failed to penetrate the market beyond early adopters and media companies.

It’s interesting to see how hands-on quality assurance testing used to be. Whether it’s glancing at NPN transistors under a microscope, dialing in the focus on a Super 8 camera, or a quick wave of the degaussing wand before a tube leaves the line, each of the QA tasks were carried out by individual employees rather than the automated methods of today. On an unrelated note, the brief overview of the Sony’s on-site “fiefdom” for its young workforce is a reminder that some ideas may be better left in the past… Google’s Mountain View campus anyone? If anything is to be gleaned from this retrotechtacular retrospective is that we could all use a little more wood-grain in our electronics these days.

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