An 80386 Upgrade Deal And Intel 486 Competitor: The Cyrix Cx486DLC

September 15, 2024 by Maya Posch 12 Comments

The x86 CPU landscape of the 1980s and 1990s was competitive in a way that probably seems rather alien to anyone used to the duopoly that exists today between AMD and Intel. At one point in time, Cyrix was a major player, who mostly sought to provide a good deal that would undercut Intel. One such attempt was the Cx486DLC and the related Tx486DLC by Texas Instruments. These are interesting because they fit in a standard 386DX mainboard, are faster than a 386 CPU and add i486 instructions. Check your mainboard though, as these parts require a mainboard that supports them.

This is something that [Bits und Bolts] over at YouTube discovered as well when poking at a TX486DLC (TI486DLC) CPU. The Ti version of the Cyrix Cx486DLC CPU increases the 1 kB L1 cache to 8 kB but is otherwise essentially the same. He found the CPU and the mainboard in the trash and decided to adopt it. After removing the very dead battery from the Jamicon KMC-40A Baby AT mainboard, the mainboard was found to be in good working order. The system fired right up with the Ti CPU, some RAM, and a video card installed.

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Taking Back The Internet With The Tildeverse

September 14, 2024 by Dave Rowntree 24 Comments

For many of us of a particular vintage, the internet blossomed in the ’90s with the invention of the Web and just a few years of development. Back then, we had the convenience of expression on the WWW and the backup of mature services such as IRC for all that other stuff we used to get up to. Some of us still hang out there. Then something happened. Something terrible. Big-commerce took over, and it ballooned into this enormously complex mess with people tracking you every few seconds and constantly trying to bombard you with marketing messages. Enough now. Many people have had enough and have come together to create the Tildeverse, a minimalist community-driven internet experience.

A collaborative Minecraft server hosted on a Tilde site

Tilde, literally ‘ ~ ‘, is your home on the internet. You can work on your ideas on a shared server or run your own. Tilde emphasises the retro aesthetic by being minimal and text-orientated. Those unfamiliar with a command line may start getting uncomfortable, but don’t worry—help is at hand. The number of activities is too many to list, but there are a few projects, such as a collaborative Sci-Fi story, a radio station, and even a private VoIP server. Gamers are catered for as long as you like Minecraft, but we think that’s how it should go.

The Tildeverse also supports Gopher and the new Gemini protocol, giving some people a few more options with which to tinker. The usual method to gain access is to first sign up on a server, then SSH into it; you’re then taken to your little piece of the internet, ready to start your minimalist journey into the Tildeverse.

A couple of videos after the break go into much more detail about the whys and hows of the Tildeverse and are worth a chunk of your time.

We’ve talked about the ‘small web’ before. Here’s our guide to Gemini.

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IBM’s 1969 Educational Computing

September 11, 2024 by Alexander Rowsell 8 Comments

IBM got their PCs and PS/2 computers into schools in the 1980s and 1990s. We fondly remember educational games like Super Solvers: Treasure Mountain. However, IBM had been trying to get into the educational market long before the PC. In 1969, the IBM Schools Computer System Unit was developed. Though it never reached commercial release, ten were made, and they were deployed to pilot schools. One remained in use for almost a decade! And now, there’s a new one — well, a replica of IBM’s experimental school computer by [Menadue], at least. You can check it out in the video below.

The internals were based somewhat on the IBM System/360’s technology. Interestingly, it used a touch-sensitive keypad instead of a traditional keyboard. From what we’ve read, it seems this system had a lot of firsts: the first system to use a domestic TV as an output device, the first system to use a cassette deck as a storage medium, and the first purpose-built educational computer. It was developed at IBM Hursley in the UK and used magnetic core memory. It used BCD for numerical display instead of hexadecimal or octal, with floating point numbers as a basic type. It also used 32-bit registers, though they stored BCD digits and not binary. In short, this thing was way ahead of its time.

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PC Floppy Copy Protection: Softguard Superlok

September 9, 2024 by Maya Posch 15 Comments

Many have sought the holy grail of making commercial media both readable and copy-proof, especially once everyone began to copy those floppies. One of these attempts to make floppies copy-proof was Softguard’s Superlok. This in-depth look at this copy protection system by [GloriousCow] comes on the heels of a part one that covers Formaster’s Copy-Lock. Interestingly, Sierra switched from Copy-Lock to Superlok for their DOS version of games like King’s Quest, following the industry’s quest in search of this holy grail.

The way that Superlok works is that it loads a (hidden) executable called CPC.COM which proceeds to read the 128 byte key that is stored on a special track 6. With this key the game’s executable is decoded and fun can commence. Without a valid ‘Play’ disk containing the special track and CPC.COM executable all one is instead left with is a request by the game to ‘insert your ORIGINAL disk 1’.

As one can see in the Norton Commander screenshot of a Sierra game disk, the hidden file is easily uncovered in any application that supports showing hidden files. However, CPC.COM couldn’t be executed directly; it needs to be executed from a memory buffer and passed the correct stack parameters. Sierra likely put in very little effort when implementing Softguard’s solution in their products, as Superlok supports changing the encryption key offset and other ways to make life hard for crackers.

Sierra was using version 2.3 of Superlok, but Softguard would also make a version 3.0. This is quite similar to 2.x, but has a gotcha in that it reads across the track index for the outer sector. This requires track wrapping to be implemented. Far from this kind of copy protection cracking being a recent thing, there was a thriving market for products that would circumvent these protections, all the way up to Central Point’s Copy II PC Option Board that would man-in-the-middle between the floppy disk drive and the CPU, intercepting data and render those copy protections pointless.

As for the fate of Softguard, by the end of the 1980s many of its customers were tiring of the cat-and-mouse game between crackers and Softguard, along with issues reported by legitimate users. Customers like Infographics Inc. dropped the Superlok protection by 1987 and by 1992 Softguard was out of business.

The Hidden Crystal Method

September 8, 2024 by Adam Fabio 25 Comments

Ever been working on a project and get stuck on one of those last little details? That’s what happened to [Empire of Scrap]. He’s building an Ohio Scientific (OSI) superboard II replica. He wants it to be accurate down to the dates on the chips. It is quite an impressive build. The problem is the crystal. OSI used large crystals, even by early 1980s standards. The crystal is in a large can with thick pins, like something you’d expect to find in old radio equipment. The problem is that this crystal package isn’t made anymore.

The crystal had to be exactly 3.932160 MHz, and while [Empire] has a huge collection of vintage crystals, he didn’t have the right one from the 70s. He did, however, have that value in a modern crystal.

The solution? Hide the new crystal in the can of an older one. The only problem is that crystals are sealed. The bottom appeared to be some sort of plastic or resin. Gong after it with a side cutter, [Empire] realized it was glass! Thankfully, none of it got in his eyes, though his hands may have taken a bit of a beating.

With the old crystal’s shell hollowed out, [Empire] installed the modern device and potted everything in resin. The transplant worked. Now, all that’s left is to fire up the OSI and start hacking.

Want to build a replica computer but don’t want to hunt down the parts? Check out [Taylor] and [Amy’s] build of this minipet. Regardless of the size of the case, crystals all work in the same way.

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Building A DIY MSX Mega Cartridge

September 7, 2024 by Dave Rowntree 9 Comments

[Mike] from Leaded Solder has a soft spot for old computers, and a chance encounter with a friend sent them deep down the deep hole that is the world of 80s and 90s-era Japanese home computers. Many people playing with these machines have all kinds of issues to deal with, such as rotting cartridges, failing components, and just dirt and mank in critical places. [Mike] decided that working on an MSX-standard custom programmable cartridge would be sensible, but then got stuck on how the MSX cartridge mapping works.

The Konami 128K scheme uses 4 to 4-of-8 mapping.

You may recall that the MSX platform is not a single computer but a standard to which many (mainly Japanese) manufacturers designed their products. This disconnected the software writers from the hardware makers and is essentially a mirror of the IBM-PC clone scene.

The MSX is based around the Z80, which has a 16-bit address bus, restricting it to 64K of ROM or RAM. The MSX has two cartridge slots, an ‘internal’ slot for the BIOS and RAM and a fourth for ‘misc’ use. Each of these is mapped internally into the physical address space. The cartridge slots have 64K of addressable space mapped into the Z80 physical space.

If this was not complicated enough, many MSX games and applications exceeded this restriction and added a layer of mapping inside the cartridge using bank switching. A register in the cartridge could change the upper bits of the address allowing ROMs larger than 64K.

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It’s Spreadsheets All The Way Down For This 80s Handheld

September 5, 2024 by Bryan Cockfield 9 Comments

Unlike the today’s consumer computer market, the 1980s were the wild west in comparison. There were all kinds of different, incompatible operating systems, hardware, and programs, all competing against one another, and with essentially no networking to tie everything together. Some of these products were incredibly niche as well, only running one program or having a limited use case to keep costs down. Such was the Convergent WorkSlate, a computer that ran only a spreadsheet with any programs also needing to be built into a spreadsheet.

Upon booting the device, the user is presented with a fairly recognizable blank spreadsheet, albeit with a now-dated LCD display (lacking a backlight) and a bespoke keyboard and cursor that wouldn’t have allowed for easy touch typing. The spreadsheet itself is quite usable though, complete with formatting tools and the capability to use formulas like a modern spreadsheet program would. It also hosted a tape deck for audio and data storage, a modem for communicating with other devices, and an optional plotter-style printer. The modem port is how [Old VCR] eventually interfaces with the machine, although as one can imagine is quite a task for a piece of small-batch technology from the 80s like this. After learning how to send and receive information, a small game is programmed into the machine and then a Gopher interface is built to give the device limited Internet connectivity.

The investigation that [Old VCR] goes into on this project to get this obsolete yet unique piece of hardware running and programmed to do other tasks is impressive, and worth taking a look at especially because spreadsheets like this aren’t Turing-complete, leading to a few interesting phenomenon that most of us wouldn’t come across in the modern computing world. Since only around 60,000 units were ever made it’s difficult to come across these machines, but if you want to take a look at the spreadsheet world of the 80s without original hardware you can still run Lotus 1-2-3 natively in Linux today.

Thanks to [Cameron] for the tip!