Fixing Bugs In A 37 Year Old Apple II Game

Emulators are a great way to reminisce about games and software from yesteryear. [Jorj Bauer] found himself doing just that back in 2002, when they decided to boot up Three Mile Island for the Apple II. It played well enough, but for some reason, crashed instantly if you happened to press the ‘7’ key. This was a problem — the game takes hours to play, and ‘7’ is the key for saving and restoring your progress. In 2002, [Jorj] was content to put up with this. But finally, enough was enough – [Jorj] set out to fix the bug in Three Mile Island once and for all.

The project is written up in three parts — the history of how [Jorj] came to play Three Mile Island and learn about Apple IIs in the first place, the problem with the game, and finally the approach to finding a solution. After first discovering the problem, [Jorj] searched online to see if it was just a bad disk image causing the problem. But every copy they found was the same. There was nothing left for it to be but problem in the binary.

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The BASIC Issue With Retro Computers

If you are interested in how a computer works at the hardware grass-roots level, past all the hardware and software abstractions intended to make them easier to use, you can sometimes find yourself frustrated in your investigations. Desktop and laptop computers are black boxes both physically and figuratively, and microcontrollers have retreated into their packages behind all the built-in peripherals that make them into systems-on-chips.
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FPGA-and-Pi Colossus Smashes Your Codes!

If it were sixty years ago, and you were trying to keep a secret, you’d be justifiably glad that [Ben North] hadn’t traveled back in time with his Raspberry-Pi-and-FPGA code-breaking machine.

We’ve seen a lot of Enigma builds here at Hackaday — the World War II era encryption machine captured our readers’ imaginations. But perhaps the more important machines to come out of cryptanalysis during that era were Turing’s electromechanical Bombe, because it cracked Enigma, and the vacuum-tube-based Colossus, because it is one of the first programmable electronic digital computers.

[Ben]’s build combines his explorations into old-school cryptanalysis with a practical learning project for FPGAs. If you’re interested in either of the above, give it a look. You can start out with his Python implementations of Colossus to get your foot in the door, and then move on to his GitHub repository for the FPGA nitty-gritty.

It’s also a cool example of a use for the XuLA2 FPGA board and its companion StickIt board that plug straight into a Raspberry Pi for programming and support. We haven’t seen many projects using these since we first heard about them in 2012. This VirtualBoy hack jumped out at us, however. It looks like a nice platform. Anyone else out there using one?

Retrocomputing on a Chip

New electrical components enable us to reconstruct old wiring more efficiently. Especially, the accessible and cheap FPGA kits which offer the possibility to put together wiring of many old computers as an “on-a-chip” solution.

When I managed to get a hold of an old bubble LED display and a pretty mechanical matrix keyboard, I decided to build a replica of an old single board computer. Logical options seemed to be to build either KIM-1 or Heathkit ET-3400. Replicas of KIM-1 already exist, even for Arduino, so my task would be reduced to connect the keyboard and display. But then I told myself that I would use the fact that my bubble display has 9 positions as an excuse to build the legendary Czechoslovak Single Board Computer PMI-80 which used the same display. My replica is an FPGA, or rather an FPGA emulator of this very computer.

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Streaming Video on an Apple IIc

Some of the projects we feature solve a problem. Others just demonstrate that they can be done. We’re guessing that it’s the latter that motivated [Joshua Bell] to write a VNC client for an Apple IIc. To fully appreciate how insane this is, have a look at the video below the break.

There’s more than one thing amazing about this hack. Somehow, [Joshua]’s VNC program runs entirely in the memory of an Apple IIc, as he demonstrates at the beginning of the video by downloading all of the code into the Apple over a serial cable. After the initial bootstrap, he runs the code and you see (in full four-color splendour!) a low-res Windows XP appear on the IIc.

2440964467_decb0daf10_oWhat’s more incredible, but is unfortunately not demonstrated in the video, is that he appears to have not just mirrored the PC’s screen on the Apple, but has actually managed to get a one-frame-per-second bi-directional VNC working at 115,200 baud. In this snapshot from his flickr gallery, he appears to be playing Karateka on the IIc and watching it on his laptop.

If you’ve got a IIc kicking around, and you want to show it yet more new tricks, don’t neglect this browser written for the Apple IIc. Or if you’ve only got an Apple IIc+ and you’re totally ticked off that the beep is different from that of the IIc, you can always go on an epic reverse-engineering quest to “repair” it.

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Vintage BBC Computer gets FPGA Buddies

The BBC Microcomputer System (or BBC Micro) was an innovative machine back in the early 1980’s. One feature that impressed reviewers was a “tube” interface that allowed the machine to become an I/O processor for an additional CPU. When the onboard 6502 became too slow, it could become a slave to a Z-80 or even an ARM processor. The bus was actually useful for any high-speed device, but its purpose was to add new processors, a feature Byte magazine called “innovative.”

[Hoglet67] has released a very interesting set of FPGA designs that allows a small board sporting a Xilinx Spartan 3 to add a 6502, a Z80, a 6809, or a PDP/11 to a BBC Micro via the tube interface. There’s something satisfying about a classic computer acting as an I/O slave to a fairly modern FPGA that implements an even older PDP/11.

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Really, Really Retro Computer On An FPGA

[Daniel Bailey] built himself a scaled-down clone of a very early computer in an FPGA. Specifically, he wrote some VHDL code to describe the machine in question, a scaled-down clone of the Manchester Small-Scale Experimental Machine with an 8-bit processor and a whopping 8 bytes of RAM, all of which are displayed on an LED screen. Too cool.

That he can get it to do anything at all with such constraints amazes us. Watch him program it and put it through its paces in the video below the break.

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