Retro Memory Hack Chat

November 1, 2021 by Dan Maloney 6 Comments

Join us on Wednesday, November 3 at noon Pacific for the Retro Memory Hack Chat with Andy Geppert!

With how cheap and easy-to-integrate modern memory chips have become, it’s easy to lose track of the fact that it wasn’t too long ago that memory was the limiting factor in most computer designs. Before the advent of silicon memory, engineers had to make do with all sorts of weird and wonderful technologies just to provide a few precious bytes of memory. Things like intricate webs of wires spangled with ferrite cores, strange acoustic delay lines, and even magnetic bubbles were all tried at one time or another. They worked, at least well enough to get us to the Moon, but none would prove viable in the face of advancements in silicon memory.

That doesn’t mean that retro memory technology doesn’t have a place anymore. Some hobbyists, like Andy Geppert, are keeping the retro memory flame alive. His Core 64 project puts a core memory module in the palm of your hand, and even lets you “draw” directly to memory with a magnet. Andy learned a few tricks along the way to that accomplishment, and wants us all to appreciate the anachronistic charm of retro memory technologies. Stop by the Hack Chat to talk about your memories of memory, or to just learn what it used to take to store a little bit of data.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, November 3 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

An Emulator For OBP, The Spaceflight Computer From The 1960s

November 1, 2021 by Donald Papp 9 Comments

[David Given] frequently dives into retrocomputing, and we don’t just mean he refurbishes old computers. We mean things like creating a simulator and assembler for the OBP spaceflight computer, which was used in the OAO-3 Copernicus space telescope, pictured above. Far from being a niche and forgotten piece of technology, the On-Board Processor (OBP) was used in several spacecraft and succeeded by the Advanced On-board Processor (AOP), which in turn led to the NASA Standard Spaceflight Computer (NSSC-1), used in the Hubble Space Telescope. The OBP was also created entirely from NOR gates, which is pretty neat.

One thing [David] learned in the process is that while this vintage piece of design has its idiosyncrasies, in general, the architecture has many useful features and is pleasant to work with. It is a bit slow, however. It runs at a mere 250 kHz and many instructions take several cycles to complete.

Sample of the natural-language-looking programming syntax for the assembler. (Example from page 68 of the instruction set manual for the OBP.)

One curious thing about the original assembler was documentation showing it was intended to be programmed in a natural-language-looking syntax, of which an example is shown here. To process this, the assembler simply mapped key phrases to specific assembly instructions. As [David] points out, this is an idea that seems to come and go (and indeed the OBP’s successor AOP makes no mention whatsoever of it, so clearly it “went”.) Since a programmer must adhere to a very rigid syntax and structure anyway to make anything work, one might as well just skip dealing with it and write assembly instructions directly, which at least have the benefit of being utterly unambiguous.

We’re not sure who’s up to this level of detail, but embedded below is a video of [David] coding the assembler and OBP emulator, just in case anyone has both an insatiable vintage thirst and a spare eight-and-a-half hours. If you’d prefer just the files, check out the project’s GitHub repository.

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The Pi Zero 2 W Is The Most Efficient Pi

November 1, 2021 by Elliot Williams 115 Comments

Last week we saw the announcement of the new Raspberry Pi Zero 2 W, which is basically an improved quad-core version of the Pi Zero — more comparable in speed to the Pi 3B+, but in the smaller Zero form factor. One remarkable aspect of the board is the Raspberry-designed RP3A0 system-in-package, which includes the four CPUs and 512 MB of RAM all on the same chip. While 512 MB of memory is not extravagant by today’s standards, it’s workable. But this custom chip has a secret: it lets the board run on reasonably low power.

When you’re using a Pi Zero, odds are that you’re making a small project, and maybe even one that’s going to run on batteries. The old Pi Zero was great for these self-contained, probably headless, embedded projects: sipping the milliamps slowly. But the cost was significantly slower computation than its bigger brothers. That’s the gap that the Pi Zero 2 W is trying to fill. Can it pull this trick off? Can it run faster, without burning up the batteries? Raspberry Pi sent Hackaday a review unit that I’ve been running through the paces all weekend. We’ll see some benchmarks, measure the power consumption, and find out how the new board does.

The answer turns out to be a qualified “yes”. If you look at mixed CPU-and-memory tasks, the extra efficiency of the RP3A0 lets the Pi Zero 2 W run faster per watt than any of the other Raspberry boards we tested. Most of the time, it runs almost like a Raspberry Pi 3B+, but uses significantly less power.

Along the way, we found some interesting patterns in Raspberry Pi power usage. Indeed, the clickbait title for this article could be “We Soldered a Resistor Inline with Raspberry Pis, and You Won’t Believe What Happened Next”, only that wouldn’t really be clickbait. How many milliamps do you think a Raspberry Pi 4B draws, when it’s shut down? You’re not going to believe it.

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DC UPS Keeps The Internet Up

November 1, 2021 by Al Williams 33 Comments

We occasionally get annoyed that so much gear takes the ubiquitous “wall wart” these days. But one advantage is that the devices operate on DC voltage. [TechRally] takes advantage of this to create an automatic DC UPS with dual outputs to power a router and modem in the event of a power outage. You can see two videos about the project below.

Some may say it would be better to use conventional UPS, but think about it. That UPS has a battery in it that gets converted to AC so the wall wart can convert it back to DC. Each conversion loses some energy, of course, and in the case of a cheap wall wart, you may even lose quite a bit.

The project contains eight 18650 batteries, an off-the-shelf charge controller, and power converters. Could you do a more efficient custom design? Maybe, but the use of these inexpensive and commonly available modules makes it quick and easy to pull something like this together.

No one would mistake this UPS for a commercial unit, but it does have a certain hacker aesthetic. We wouldn’t carry it through an airport, though. With those digital displays and all the wiring, it looks like a bad TV show’s bomb prop.

If you don’t care about the automatic switchover, we hear that 5V will power a lot of equipment these days and that makes battery operation as simple as stripping a USB cable. This could probably drive some other gear like a connected Raspberry Pi. Or, you could do that job with some supercaps.

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Hacking An Obsolete Yet Modern Calculator

November 1, 2021 by Bryan Cockfield 7 Comments

The gold standard for graphing calculators, at least in the US, are the Texas Instruments TI-84 series. Some black sheep may have other types, but largely due to standardized testing these calculators dominate the market. Also because of standardized testing, these calculators have remained essentially unchanged for decades. While this isn’t great for getting value for money, it does mean that generations of students have been able to hack on these calculators to do all kinds of interesting things as [George Hilliard] outlines.

Even before the creation of these graphing calculators, the z80 processor behind them was first produced over four decades ago and was ubiquitous in the computer scene at the time, which also lends to its hackability. There’s plenty to catch up on here, too, from custom TI games that trick the two-tone display into grayscale to Game Boy emulators that can play Zelda since the TI and Game Boy share the same processors. There are also several methods of running native code or otherwise “jailbreaking” these devices to run arbitrary code.

It looks like the world of TI hacking is alive and well now, and with several decades of projects to browse there’s always something new to find. As it stands, there may be more decades of these types of projects to come, since neither TI nor the various testing standardization companies and government agencies show any signs of changing any time soon.

Thanks to [Adrian] for the tip!