Retrocomputing

1169 Articles

An Amiga 500 with a blue case and blue accessories

Restored Amiga 500 Is Blue – And Glows In The Dark

July 21, 2023 by 5 Comments

Few things are as satisfying to watch as a good retrocomputer restoration project – we’re always happy to see someone bring a rusty old Commodore, Apple or Atari back to life. The goal is typically to get the machine as close to its original state as possible, except for perhaps a few non-intrusive mods like memory upgrades. [Drygol] however, had already done this so many times that he thought it was time to take a different route for once, and apply some creativity to an old Amiga 500 case. Originalists may shudder, but we quite like his funky blue-and-yellow A500 mod.

An Amiga 500 with a poor blue-and-yellow paint job
Missing keys, random stickers and an ugly paint job: the A500 wasn’t looking great at the beginning

To be fair, [Drygol] wasn’t the first one to modify this specific Amiga’s case: one of its previous owners had already applied a rather shoddy blue paint job and defaced it with some stickers. [Drygol] decided to stick with the basic idea, but do it right this time. First he removed the old paint using concentrated lye, then gave it a fresh coat of blue. He also applied glow-in-the-dark paint to the Amiga logo embossed in the case and added a fluorescent yellow laser-cut circuit board ornament. It took a bit of experimenting to get all these elements just right, but the end result definitely looks the part.

The insides of the Amiga also needed some TLC: [Drygol] competely cleaned and lubricated the floppy drive, gave the motherboard a good ultrasonic scrub, and replaced dodgy capacitors all over. He expanded the RAM from 512 kB to 1 MB and added a Gotek floppy emulator, which can work in parallel with the original disk drive. To make the Gotek easy to operate, [Drygol] placed its OLED screen and a pair of touch-sensitive buttons in a cutout on the front of the case.

A matching blue mouse and gamepad, both connected through the MouSTer adapter, complete the setup. The result is a good-looking A500 with some modern conveniences that’s perfect for exploring the Amiga’s extensive software library. If custom colors aren’t your thing, you’ll be happy to know that the original shade of grey or beige might be available for your retro console, too.

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Old Style 1802 Computer Has MMU

July 21, 2023 by 8 Comments

When you think of an MMU — a memory management unit — you probably think of a modern 32-bit computer. But [Jeff Truck] has a surprise. His new RCA 1802 computer has bank switching, allowing the plucky little processor to address 256K of RAM. This isn’t just the usual bank-switching design, either.

The machine has several unique features. For example, an Arduino onboard can control the CPU so that you can remotely control the bus. It does not, apparently, stand in for any of the microprocessor support chips. It also doesn’t add additional memory or control its access.

The 256K of memory is under the control of the MMU board. This board generates two extra address bits by snooping the executing instruction and figures out what register is involved in any memory access. Memory in the MMU stores a table that lets you set different memory pages for each register. This works even if the register is not explicit and also for the machine’s DMA and instruction fetch cycles. If you know about the RCA “standard call and return technique,” which also needed a little patching for the MMU. [Jeff] covers that at the end of the video below.

This is a very simple version of a modern MMU and is an impressive trick for a 50-something-year-old CPU. We were surprised to hear — no offense to [Jeff] — that the design worked the first time. Impressive! There’s also some 3D printing and other tips to pick up along the way. But we were super impressed with the MMU. You might never have to do this yourself (although you could), but you can still marvel that it can be done at all.

We have a soft spot for the 1802s, real or emulated. The original ELF was great, but 256K is a lot better than the original 256 bytes!

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An Easy Z80 And VGA Upgrade For The Apple II

July 20, 2023 by 15 Comments

The Apple II was at the forefront of the home computer revolution when it came out in 1977. In its era, nobody really cared about hooking up the Apple II to a VGA monitor, but these days, it’s far easier than sourcing an original monitor. The V2 Analog is a useful tool that will let you do just that, plus some other neat tricks, besides.

As demonstrated on Youtube by [Adrian’s Digital Basement], The V2 Analog is basically a slot-in video card for the Apple II, II+, and IIe. It’s based upon the AppleII-VGA, which uses a Raspberry Pi Pico to snoop the 6502 CPU bus and copy the video memory. It then outputs a high-quality VGA signal that is far nicer than the usual composite output options.

As a bonus, the V2 Analog can be reconfigured to run as an emulated AppliCard Z80 expansion card instead. This card was originally intended to allow Apple II users to run CP/M applications. The V2 Analog does a great job in this role, though it bears noting it can’t handle VGA output and Z80 emulation at the same time.

Project files are available on Github for the curious. The Apple II may be long out of production, but it’s certainly not forgotten. Video after the break.

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TV Typewriter Remembered

July 20, 2023 by 22 Comments

With the recent passing of Don Lancaster, I took a minute to reflect on how far things have come in a pretty short period of time. If you somehow acquired a computer in the early 1970s, it was probably some discarded DEC, HP, or Data General machine. A few people built their own, but that was a stout project with no microprocessor chips readily available. When machines like the Mark-8 and, more famously, the Altair appeared, the number of people with a “home computer” swelled — relatively speaking — and it left a major problem: What kind of input/output device could you use?

An ad from Kilobaud offered you a ready-to-go, surely refurbished, ASR33 for $840

At work, you might have TeleType. Most of those were leased, and the price tag of a new one was somewhere around $1,000. Remember, too, that $1,000 in 1975 was a small fortune. Really lucky people had video terminals, but those were often well over $1,500, although Lear Siegler introduced one at the $1,000 price, and it became wildly successful. Snagging a used terminal was not very likely, and surplus TeleType equipment was likely of the 5-bit Baudot variety — not unusable, but not the terminal you really wanted.

A lot of the cost of a video terminal was the screen. Yet nearly everyone had a TV, and used TVs have always been fairly cheap, too. That’s where Don Lancaster came in. His TV Typewriter Cookbook was the bible for homebrew video displays. The design influenced the Apple 1 computer and spawned a successful kit for a company known as Southwest Technical Products. For around $300 or so, you could have a terminal that uses your TV for output. Continue reading “TV Typewriter Remembered” →

PCjr WebServer Hits 2500 Hours Uptime

July 20, 2023 by 23 Comments

When [Mike] fired up his PCjr webserver back in March, he probably wasn’t expecting it to go viral. 2640 hours later, here we are! Not only has his machine run continuously for over 110 days, it also is surviving a global hug of death. All of this is thanks to some very special software.

We see lots of old machines here on Hackaday. We also see lots of minimal web servers. But we don’t see many that can run for thousands of hours, offering up to 8 simultaneous connections. Curious if jr is still up? Check brutmanlabs.org. The whole website is hosted on the 40-year-old machine. If you want to be a bit more kind, here’s a direct link to the text-only status page. While many of those hours were idle, currently lots of folks are hitting that little V20 CPU, so please give it a few seconds to respond.

The PCjr has a few upgrades — the aforementioned V20 CPU upgrade, a jrIDE sidecar, and a memory upgrade to 736 kB to name a few.  Ethernet connectivity is via a Xircom parallel port adapter – which is circa 1993.  The operating system is IBM PC DOS 5.02. One thing to note is that all these upgrades were possible back in the mid-1980’s when the PCjr was still current.  [Mike] could run the system with an MFM hard drive, an ISA ethernet card (via an adapter), and use the original CRT monitor. Older DOS versions would work too — though partition sizes would be limited. The “modern” conveniences are just to keep from wearing out vintage hardware which is quickly becoming rare.

The real glue that holds this all together is [Mike’s] own software: mTCP. mTCP is a full set of tools for running internet applications on systems running MS-DOS or a compatible OS. We’ve seen quite a few mTCP projects over the years.  [Mike] has worked tirelessly testing the software, ensuring that it is stable and reliable.

Software is never perfect though – one thing [Mike] didn’t implement is a log roller. Since he has logging turned on, the PCjr was slowly filling up its hard drive. Once the drive was full, mTCP would perform an orderly shutdown — but the uptime will be reset.  [Mike] was able to go in and switch off logging with  DOS’s DEBUG command. A live patch is not the way one would normally update software – but the fact that he was able to do it shows how deep [Mike’s] knowledge of the software goes.

[Mike] has even provided a live stream recording of the little PCjr handling requests from all over the globe.

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PCMCIA Flash Card Gives Up Its Secrets Thanks To Retro Gear

July 18, 2023 by 27 Comments

There are two ways to recover data from an obsolete storage medium. One way is to pull out all the tools in the hacker’s kit — with logic analyzers, oscilloscopes, and bit-banged software in a desperate attempt to reverse engineer the original protocol. The other way is to have a really, really deep junk bin that just happens to contain exactly the right pieces that would have been used decades ago.

For recovering data from a 25-year-old PCMCIA memory card, [Dave] from Vintage Apparatus chose the latter method. But to be fair, characterizing the stash of gear he had to select from as a “junk bin” is pretty insulting. It’s more like a museum of retro technology, which just so happened to hold  Toshiba Libretto, a subnotebook computer hailing from the late 1990s. The machine sports a pair of PCMCIA slots and was just the thing to read the data from the old 32 MB SanDisk flash card, which once lived in a backpack-mounted GPS system for surveyors.

If this hack sounds as easy as plugging things into an old computer, you’d be right — if you just happen to have a stack of floppies containing the Windows 98 drivers for said things. So [Dave]’s task became a game of finding the right combination of cards that already had the drivers installed and would provide the connectivity needed to get the data off the flash card. Between a suspiciously crunchy-sounding floppy drive and an Ethernet card dongle badly in need of some contact cleaner, cobbling together the right hardware was a bit of a chore. After that, a lot of the hack was [Dave] just remembering how we used to do things back in the day, with the eventual solution being transferring over the files to an FTP server on a Raspberry Pi.

The video below tells the whole saga, but the real treat might just be the Vintage Apparatus collection of gear. Incidentally, we really like [Dave]’s idea for storing associated bits and bobs.

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Do You Have An Old Hitachi Computer? You Might Just Have BeOS Without Realizing It

July 18, 2023 by 43 Comments

There was a moment in the years spanning the move from 16-bit platforms to 32-bit, during which it looked for a moment as though there might be a few new operating system contenders making a mark on the desktop.

A 1990s Hitachi Flora Prius PC, from the Hitachi press release.
Does this PC look familiar to you?

This was the period that gave rise to the “Year of Linux on the desktop” meme as the open source contender just wasn’t ready for the general public, but we all know what happened. The various commercial contenders slipped by the wayside or survived by the skin of their teeth as enthusiast or niche platforms, while Microsoft Windows steamrollered all before it except for the walled garden of Apple users.

One of the players was BeOS, a powerful multimedia OS that might have had a chance if it could have persuaded OEMs to ship it on some PCs, but in that endeavour it had no luck. Or so everyone thought, but [Thom Holwerda] reports on the fascinating tale of a PC that shipped with BeOS, but not in a way anyone could easily use.

It seems that even being seen to talk to the folks from Be was enough to ensure an OEM received a visit from Microsoft goons sales representatives so even though the rival OS was offered for free it received no PC takers. This was the received opinion, but it turns out that the one manufacturer which did include BeOS was Hitachi, in Japan. Their Flora Prius PC was a Pentium II equipped white box typical of late-90s multimedia hardware, and though it booted into Windows it also had a BeOS installation on board that probably very few owners would have even realised existed. It seems Hitachi did the deal with Be but didn’t install the required bootloader to use the Be partition. A Flora Prius owner could run the software if they were prepared to follow some instructions on the Be website and download a floppy image, but it seems very few did so.

All this leads to a fascinating challenge for today’s BeOS enthusiasts, to locate a surviving Flora Prius PC if any can still be found with an intact BeOS partition, and activate the only factory PC BeOS install. We know we have readers in Japan who almost certainly have an eye for an old computer, can any of you help them in this quest?

We’ve touched on BeOS in the past on its own BeBox platform and the elusive Sony eVilla internet appliance.