Rewritable ROM for the Mac Plus

The Macintosh Classic – a small all-in-one computer with a 9″ monochrome screen –  was one of the more interesting machines ever released by Apple. It was the company’s first venture into a cost-reduced computer, and the first Macintosh to sell for less than $1000. Released in 1990, its list of features were nearly identical to the Macintosh Plus, released four years earlier. The Classic also had an interesting feature not found in any other Mac. It could boot a full OS, in this case System 6.0.3, by holding down a series of keys during boot. This made it an exceptional diskless workstation. It was cheap, and all you really needed was a word processor or spreadsheet program on a 1.44 MB floppy to do real work.

[Steve] over at Big Mess O’ Wires had the same idea as the Apple engineers back in the late 80s. Take a Macintosh Plus, give it a bit more ROM, and put an OS in there. [Steve] is going a bit farther than those Apple engineers could have dreamed. He’s built a rewritable ROM disk for the Mac Plus, turning this ancient computer into a completely configurable diskless workstation.

The build replaces the two stock ROM chips with an adapter board filled with 29F040B Flash chips. They’re exactly what you would expect – huge, old PDIPs loaded up with Flash instead of the slightly more difficult to reprogram EEPROM. Because of the additional space, two additional wires needed to connected to the CPU.  The result is a full Megabyte of Flash available to the Macintosh at boot, in a computer where the normal removable disk drive capacity was only 800kB.

The hardware adapter for stuffing these flash chips inside a Mac Plus was made by [Rob Braun], while the software part of this build came from [Rob] and [Doug Brown]. They studied how the Macintosh Classic’s ROM disk driver worked, and [Rob Braun] developed a stand-alone ROM disk driver with a new pirate-themed startup icon. [Steve] then dug in and created an old-school Mac app in Metrowerks Codewarrior to write new values to the ROM. Anything from Shufflepuck to Glider, to a copy of System 7.1  can be placed on this ROM disk.

This isn’t the first time we’ve seen ROM boot disks for old Macs. There was a lot of spare address space floating around in the old Mac II-series computers, and [Doug Brown] found a good use for it. Some of these old computers had optional ROM SIMM. You can put up to 8 Megabytes  in the address space reserved for the ROM, and using a similar ROM disk driver, [Doug] can put an entire system in ROM, or make the startup chime exceptionally long.

ZX81 Emulated on an mbed

This is a wonderful example of the phenomenon of “feature creep”. [Gert] was working on getting a VGA output running on an mbed platform without using (hardly) any discrete components. Using only a few resistors, the mbed was connected to a VGA display running at 640×480. But what could he do with something with VGA out? He decided to emulate an entire Sinclair ZX81 computer, of course.

With more than 1.5 million units sold, the Sinclair ZX81 was a fairly popular computer in the early ’80s. It was [Gert]’s first computer, so it was a natural choice for him to try to emulate. Another reason for the choice was that his mbed-VGA device could only output monochrome color, which was another characteristic of the ZX81.

[Gert] started by modifying a very lean Z80 emulator to make the compiled code run as efficiently as possible on the mbed. Then he went about getting a picture to display on the screen, then he interfaced an SD card and a keyboard to his new machine. To be true to the original, he built everything into an original ZX81 case.

This isn’t the first time we’ve seen a ZX81, but it is one of the better implementations of an emulated version of this system we’ve seen.

Thanks to [Jeroen] for the tip!

The Heathkit Mystery

Heathkit is a company that requires no introduction. From the mid-40s until the 90s, Heathkit was the brand for electronic kits ranging from test equipment, HiFis, amateur radio equipment, computers, to freakin’ robots. Their departure was a tragic loss for generations of engineers, electronic tinkerers and hobbyists who grew up with these excellent and useful kits.

Although Heathkit is dead, 2013 brought an announcement that Heathkit was back in the biz. A Facebook page was launched, a Reddit AMA was held, and the news was that Heathkit would rise from the dead in the first half of 2014. It’s now Christmas, 2014, and there’s no sign of Heathkit anywhere. Adafruit has been keeping a watchful eye on the on the (lack of) developments, and the only surprising thing to report is that there is nothing to report. There has been no new announcement, there are no new products, the “official” Heathkit website hasn’t been updated in a year, and no one knows what’s going on.

Adafruit has decided to dig into the matter, and while they’ve come up with a few items of note, there’s not much to report. A trademark for ‘HEATHKIT’ was filed October 27, 2014 – two months ago. An email was sent to the attorney of record and there has been no response.

This trademark was granted to Heathkit Company, Inc., incorporated in Delaware. Searching for any companies in Delaware using the Heathkit name returns exactly two results: Heathkit Company, Inc., and Heathkit Holdings, Inc.. Adafruit is probably going to pay the $20 to the Delaware Department of State to get the detailed information that includes Heathkit’s tax assessment and tax filing history.

The last bit of information comes from a whois on the domain. The relevant contacts have been emailed, and there are no further details. The Heathkit virtual museum was contacted for information, as was the news editor for Nobody knows anything, or at least nobody is telling anybody anything.

To date, the only physical evidence of Heathkit’s rebirth is a geocache that was left at Brooklyn Bridge Park, announced during the Reddit AMA. This geocache was recovered by reddit user IFoundTheHeathKit, a throwaway account that had no posts before or since finding the cache. We have no idea what was in that geocache, what the ‘secret passphrase’ or set of instructions was, or if anything ever came of the promise to send one of the first new kits.

So there ‘ya go. A lot of words but no information. If you have any info, the Adafruit crew would like to have a word with you.


The person who found the Heathkit geocache has been found:










The full comment referred to below is,

Hey, person who found the Heathkit geocache here. The secret passcode was an Einstein quote about radio vs wired communication (invisible cats), and they said they’d send me something in early 2014. Never had any communication except through FB, and they haven’t replied to any of my recent messages.

IFoundTheHeathKit might want to email Adafruit with a copy of all the emails.

Meme Themed Pinball Machine – Much Flipping, Y U No Win?!

Summoning 4chans, 9gags, Reddits and other denizens of easily-digested content, Liberty Games stripped apart a dilapidated “Baby Doll” pinball arcade machine and turned it into this meme-spouting monstrosity. A complete redo of the vinyl and graphics to sport dozens of familiar internet tropes was first, then they had Shapeways create internal scenery and finally some electronics were added to spice things up.

We have seen PINMAME-based digital machines but this took a different path. Pinball machines this old pre-date common transistors so they rely on electro-mechanicals for everything. This made hacking the machine challenging so the team intercepted most of the signals and tied them into a Raspberry Pi with a Pi-face interface board. A videoscreen was added to the scoreboard, triggering all manner of memey videos and sounds according to actions performed and unlocked on the screen.

If you yearn for expired pranks of years gone by and are bad at pinball, you are in luck. Losing the game gets you Rickrolled – over and over again. On the plus side, Nyan Cat rockets away to bonuses and even the Admiral himself warns you of impending danger.

We resisted the urge to write this article as a chain of one meme to the next, you will get plenty of that from the well-documented project conversion and the following video. Someone in the comments will probably make a list of all memes.

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Boy Off The Grid For Years Writes GUI for DOS

In a hacker version of Jumanji, when [fiberbundle]’s parents divorced, his thrice-fugitive new stepfather took him to a remote location in Australia without any access to technology or the outside world. With him he brought an old 486, a gift from his real dad. Lest the police discover them, [fiberbundle] was forbidden contact from most of society and even restricted in the books he was allowed to read.

The boy spent years trying to get the most he could out of his two-generations-old PC. Using only two textbooks from a decade and a half earlier, DOS 6.0, and QBasic he managed to write his own shell dubbed OSCI (pronounced “Aussie”), a ray-caster 3d engine and lots more. No mentors, no Internet. The computers at school were even more outdated Power Macs.

Eventually life returned him to civilization to be mindblown by modern technology 1000x as powerful. He went from playing text-based adventures he had to write for himself, to seeing Crysis. From QBasic to C++. From ASCII art “shooters” to Half-Life 2. From a 486 to a 4-core CPU. From a rural library to Wikipedia.

Follow the link above to see screens of his projects over the years. As of yet no one has verified the story, but, even if only that it is worth a read.

Thanks [Gustavo] for the tip.

Meet Registroid – Mutant Cash Register Music Sequencer

73 years ago WWII was in full swing, the world’s first computer had not yet crunched atomic bomb physics and department store cash registers had to add up your purchases mechanically. Back then, each pull caused the device to whirl and kerchunk like a slot machine. [David] & [Scott] kidnapped one of those clunkers and forced it to sing a new tune. Thus the Registroid was born, a self-described “mutant vintage cash register that is a playable, interactive electro-house looping machine.” Why did no one else think of this yet?

Inside, the adding gears and tumbling counters were gutted to make room for the electronics, amp and speaker. Keys were converted to Arduino inputs that then feed to MAX/MSP which serves as a basic midi controller. On top, five “antennae” lamps with LEDs serve as a color organ where they pulse with the audio as split up by an MSGEQ7 equalizer chip. Each row of latching keys corresponds to a different instrument: drum beats, baselines, synths, and one-shots.

We have seen similar things done to a Game Boy and typewriter before, but a cash machine is new to us. Perhaps someday someone will flip the trend and type their twitter messages from an antique harpsichord.

The Registroid appears quite popular when on display at local events, including some wonder when a secret code opens the cash drawer.

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Home Computers Behind The Iron Curtain

I was born in 1973 in Czechoslovakia. It was a small country in the middle of Europe, unfortunately on the dark side of the Iron Curtain. We had never been a part of Soviet Union (as many think), but we were so-called “Soviet Satellite”, side by side with Poland, Hungary, and East Germany.

My hobbies were electronics and – in the middle of 80s – computers. The history of computers behind the Iron Curtain is very interesting, with a lot of unusual moments. For example – communists at first called cybernetics as “bourgeois’ pseudoscience” (as well as sociology or semiotics), “used to enslave a mankind by machines”. But later on they understood the importance of computers, primarily for science and army. So in 50s the Eastern Bloc started to build its own computers, separately and “in its own way.”

The biggest problem was a lack of modern technologies. There were a lot of skilled and clever people in eastern countries, but they had a lot of problems with the elementary technical things. Manufacturing of electronics parts was divided into diverse countries of Comecon – The Council for Mutual Economic Assistance. In reality, it led to an absurd situation: You could buy the eastern copy of Z80 (made in Eastern Germany as U880D), but you couldn’t buy 74LS00 at the same time. Yes, a lot of manufacturers made it, but “it is out of stock now; try to ask next year”. So “make a computer” meant 50 percent of electronics skills and 50 percent of unofficial social network and knowledge like “I know a guy who knows a guy and his neighbor works in a factory, where they maybe have a material for PCBs” at those times.

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