Game Cartridges And The Technology To Make Data Last Forever

December 3, 2020 by Maya Posch 69 Comments

Game cartridges are perhaps the hardiest of all common storage schemes. Short of blunt traumatic force or application of electrical surges to the cartridge’s edge connectors, damaging a game cartridge is hard to do by accident. The same is also true for the data on them, whether one talks about an Atari 2006 cartridge from the late 1970s or a 1990s Nintendo 64 cartridge.

The secret sauce here are mask ROMs (MROM), which are read-only memory chips that literally have the software turned into a hardware memory device. A mask layer unique to each data set is used when metalizing the interconnects during chip fabrication. This means that the data stored on them is as durable as the processor in the game console itself. Yet this is not a technology that we can use in our own hobby projects, and it’s not available for personal long-term data storage due to the costs associated with manufacturing what is essentially a custom chip.

Despite its value as truly persistent storage, MROM has fallen out of favor over the decades. You may be surprised to find a lot of what’s currently used in the consumer market is prone to data corruption over time spans as short as one year to one decade depending on environmental conditions.

So what are we to do if we need to have read-only data that should remain readable for the coming decades?

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Hackaday Links: August 4, 2019

August 4, 2019 by Dan Maloney 22 Comments

Is the hacking community facing a HOPEless future? It may well be, if this report from 2600 Magazine is any indication. The biennial “Hackers On Planet Earth” conference is in serious financial jeopardy after the venue that’s hosted it for years, the Hotel Pennsylvania in Manhattan, announced a three-fold increase in price. Organizers are scrambling to save the conference and they’re asking for the community’s help in brainstorming solutions. Hackaday was at HOPE XI in 2016 and HOPE XII in 2018; let’s HOPE we get to see everyone again in 2020.

If you’ve ever been curious about how a 1970s PROM chip worked, Ken Shirriff has you covered. Or uncovered, as he popped the top off a ceramic MMI 5300 DIP to look at the die within. Closeups of the somewhat cockeyed die reveal its secrets – 1,024 tiny fusible links. Programming was a matter of overloading a particular fuse, turning a 1 into a 0 permanently. It’s a fascinating look at how it used to be done, with Ken’s usual attention to detail in the documentation department.

We had a great Hack Chat this week with Mihir Shah from Royal Circuits. Royal is one of the few quick-turn PCB fabs in the USA, and they specialize in lightning-fast turnaround on bare PCBs and assembled boards. He told us all about this fascinating business, and dropped a link to a side project of his. Called DebuggAR, it’s an augmented reality app that runs on a smartphone and overlays component locations, signal traces, pinouts, and more right over a live image of your board. He’s got a beta going now for iPhone users and would love feedback, so check it out.

With all the cool things you can do with LoRa radios, it’s no wonder that wireless hobbyists have taken to pushing the limits on what the technology can do. The world record distance for a LoRa link was an astonishing 702 km (436 miles). That stood for two years until it was topped, twice in the same day. On July 13th, the record was pushed to 741 km, and a mere five hours later to 766 km. All on a scant 25 mW of power.

Linux distro Manjaro made an unconventional choice regarding which office suite to include, and it’s making some users unhappy. It appears that they’ve dumped LibreOffice from the base install, opting instead to include the closed-source FreeOffice. Worse, FreeOffice doesn’t have support for saving .doc and OpenDocument files; potentially leaving LibreOffice users stranded. Paying for an upgrade to SoftMaker’s Office product can fix that, but that’s hardly free-as-in-beer free. It’s kind of like saying the beer is free, but the mug is an upgrade. UPDATE: It looks like the Manjaro team heard all the feedback and are working on a selector so you can install the office suite of your choice.

Tragic news out of New Hampshire, as amateur radio operator Joe Areyzaga (K1JGA) was killed while trying to dismantle an antenna tower. Local news has coverage with no substantial details, however the hams over on r/amateurradio seem to have the inside line on the cause. It appears the legs of the tower had filled with water over the years, rusting them from the inside out. The tower likely appeared solid to Joe and his friend Mike Rancourt (K1EEE) as they started to climb, but the tower buckled at the weak point and collapsed. K1EEE remains in critical condition after the 40′ (12 m) fall, but K1JGA is now a silent key. The tragedy serves as a reminder to everyone who works on towers to take nothing for granted before starting to climb.

And finally, just for fun, feast your eyes on this movie of the ESA’s Rosetta spacecraft as is makes its flyby of comet 67P/Churyumov–Gerasimenko. It’s stitched together from thousands of images and really makes 67P look like a place, not just a streak of light in the night sky.

Vintage Terminal Converted For Galactic Use In Time For May The Fourth

May 4, 2019 by Dan Maloney 12 Comments

“Not as clumsy or random as Windows. An elegant terminal, for a more civilized age.” [Ben Kenobi] might well have said that about the Hewlett-Packard 264x-series of serial terminals, in use starting at just about the time the original installment of the Star Wars franchise was released. With their wide-screen CRTs and toaster-oven aesthetic, they were oddballs in the terminal market, and [CuriousMarc] has gone and made one even odder by converting an H-P 2645A to display the Aurebesh character set from the movies.

A look under the hood of this lovely bit of retrocomputing history makes one think the designers almost foresaw the need to add support for a made-up language nearly half a century later. The terminal has a backplane and bus for pluggable cards, one of which carries the ROMs that [Marc] extracted and reprogrammed with the Aurebesh characters. He had a little trouble at first, needing to bodge the chip select and forgetting that he had made other “special modifications” to the terminal. The video below shows the results, along with some fatherly mortification of his daughters and a suitable tribute to the lately late [Peter Mayhew], he who donned the Wookiee suit and made a seven-foot space Sasquatch lovable.

Need more for you “May the Fourth” fix? How about a clumsy and random blaster, a cosplay speeder bike, or a fleet of droids?

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Blast From The Past With Space Station PROM Reader

November 9, 2017 by Lauren Faris 11 Comments

The Ursa Major Space Station SST282 is a dinosaur of a digital reverb. Okay, so maybe 1978 isn’t ancient yet, but it is getting to the point where one has to worry about the possibility of component failure. At least that’s what [Obsoletetechnology] thought when they created a backup of its memory contents.

As can be seen from some of Hackaday’s previous articles, a part does not have to be an older one to fail. However, there is no such thing as being too paranoid when it comes to older parts reaching their lifetime. Especially when there is valuable memory involved. Each bit of PROM memory is locked by a fuse on its location grid to store permanent data. To be able to read this and collect the respective data, a Raspberry Pi 3 PROM reader was created.

The SST282 uses 3 TTL-level 74xx series Schottky PROM memories on board that hold RAM lookup tables. In the case that these failed, all of the subsequent information would be lost since there are no surviving memory dumps online. Fortunately we are interested only in gathering their contents, so the PROM reader schematic is fairly rudimentary. The chip’s address and data buses connect to a Pi’s GPIO header, and the only other thing to note is a 74LS541 TTL level shifter that converts the Pi’s 3.3V output to the PROM’s 5V TTL level.

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Weird CPU

August 6, 2016 by Al Williams 24 Comments

How many instructions does [agp.cooper’s] computer have? Just one. How many strip boards does it use? Apparently, 41 five 41-track boards. While being one shy from the answer to life, it is still a lot of boards for a single instruction. The high board count is due to the use of 1970’s vintage ICs including TTL parts, 2114 RAM chips, and 74S571 PROMs.

There are several different architectures for single instruction computers and [agp’s] uses what is technically at TTA (transfer-triggered architecture). That is, the one instruction is a move and the destination or source of the move determines the operation. For example, the Wierd CPU (that’s the name of it) has a P and Q register. If you load those registers and then the ADD register will contain the sum of the two numbers.

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Dumping Old PROMs With New Hardware

July 11, 2015 by Brian Benchoff 34 Comments

[ijsf] recently came across a very old synthesizer from a defunct West German company. This was one of the first wavetable synths available, and it’s exceptionally rare. Being so rare, there isn’t much documentation on the machine. In an attempt at reverse engineering, [ijsf] decided to dump the EPROMs and take a peek at what made this synth work. There wasn’t an EPROM programmer around to dump the data, but [ijsf] did have a few ARM boards around. It turns out building a 27-series PROM dumper is pretty easy, giving [ijsf] an easy way to dig into the code on this machine.

The old EPROMs in this machine have 5v logic, so [ijsf] needed to find a board that had a ton of IOs and 5v tolerant inputs. He found the LPC2148, which has a nice USB system that can be programmed to dump the contents of a PROM over serial. Interfacing the PROM is as simple as connecting the power and ground, the address lines, data, and the signal lines. After that, it’s just a matter of stepping through every address according to the timing requirements of the PROM. All the data was dumped over a serial interface, and in just a few seconds, [ijsf] had 32768 bytes of ancient data that made this old synth tick.