Retrotechtacular: Transputer

April 19, 2019 by Jenny List 103 Comments

Back in 2016, Hackaday published a review of The National Museum of Computing, at Bletchley Park. It mentions among the fascinating array of computer artifacts on display a single box that could be found in the corner of a room alongside their Cray-1 supercomputer. This was a Transputer development system, and though its architecture is almost forgotten today there was a time when this British-developed microprocessor family had a real prospect of representing the future of computing. So what on earth was the Transputer, why was it special, and why don’t we have one on every desk in 2019?

An Inmos RAMDAC (the 28-pin DIP) on the motherboard of a 1989 IBM PS/55. Darklanlan [CC BY 4.0]

Inmos, based in Bristol, were a — no, make that the — British semiconductor company, in the days when governments saw such things as a home-grown semiconductor manufacturing capability to be of strategic importance. They made microcomputer peripheral chips, RAM chips, and video chips (the workaday silicon of 1980s computing) but their exciting project was the Transputer.

This microprocessor family addressed the speed bottlenecks inherent to conventional processors of the day by being built from the ground up to be massively multiprocessor. A network of Transputer processors would share a web of serial interconnects arranged in a crosspoint formation, allowing multiple of them to connect with each other independently and without collisions. It was the first to feature such an architecture, and at the time was seen as the Next Big Thing. All computers were going to use Transputers by the end of the 1990s, so electronic engineering students were taught all about them and encountered them in their group projects. I remember my year of third-year EE class would split into groups, each of tasked with a part of a greater project that would communicate through the crosspoint switch at the heart of one of the Transputer systems, though my recollection is that none of the groups went so far as to get anything to work. Still how this machine was designed is fun to look back on in modern times. Let’s dig in!

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All You Need To Know About I2S

April 18, 2019 by Jenny List 24 Comments

Last month we marked the 40th birthday of the CD, and it was as much an obituary as a celebration because those polycarbonate discs are fast becoming a rarity. There is one piece of technology from the CD age that is very much still with us though, and it lives on in the standard for sending serial digital audio between chips. The protocol is called I²S and comes as a hardware peripheral on many microcontrollers. It’s a surprisingly simple interface that’s quite easy to work with and thus quite hackable, so it’s worth a bit of further investigation.

It’s A Simple Enough Interface

Don’t confuse this with the other Philips Semiconductor protocol: I²C. Inter-Integrated Circuit protocol has the initials IIC, and the double letter was shortened to come up with the “eye-squared-see” nomenclature we’ve come to love from I²C. Brought to life in 1982, this predated I²S by four years which explains the somewhat strange abbreviation for “Inter-Integrated Circuit Sound”.

The protocol has stuck around because it’s very handy for dealing with the firehose of serial data associated with high-quality digital audio. It’s so handy that you’ve likely heard of it being used for other purposes than audio, which I’ll get to in a little bit. But first, what does I²S actually do?

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Bone Conducting Headphones Built Into Eye Glasses

April 18, 2019 by Jenny List 21 Comments

There are times when being seen to listen to music through headphones might get you into trouble. For these moments, reach for a handy solution: bone conduction speakers that discreetly pipe the music to your eardrums through the bone of your skull. [Samuel] wanted just such a covert music listening device, so created his own in a set of 3D-printed glasses.

He first tried using an Adafruit bone-conducting transducer but found that to be too bulky. What you see here is a smaller module that [Samuel] found on AliExpress (search for bone conduction module). The GD-02 is much smaller and thus more suitable for hiding in the arm of a pair of glasses. For the rest of the electronics he used a PCB and battery from a donated set of broken Bluetooth headphones, a space for which he was able to conceal easily in the 3D-printed frame of the glasses. The battery is in one arm and the board in the other, and he says the wiring was extremely fiddly.

The result is a surprisingly svelte set of specs that you might not immediately think concealed some electronics. His choice of bright yellow filament might give the game away, but overall he’s done a great job. This certainly isn’t the first bone conduction project we’ve shown you, some of the others have used motors instead of bone conduction transducers.

Rooting Your Ride: Jailbreaking A Subaru QNX

April 16, 2019 by Jenny List 18 Comments

A modern car still drives in the same way as the one you would have bought thirty years ago, it still has a steering wheel and all the other controls. What has changed in the cabin lies mostly beneath the dash, where enough computing power to launch several Moon shots takes care of everything from air-conditioning to entertainment. As you might expect these systems attract the curiosity of security researchers, and through their work we gain an insight into their operation.

[Scott Gayou] has a Subaru, a car that has an all-in-one entertainment system head unit that is typical of what you’d find across a host of manufacturers. His account of jailbreaking it is a lengthy essay and a fascinating read for anyone. He starts with a serial port, then an SSH prompt for a root password, and a bit of searching to find it was made by Harman and that it runs the closed-source realtime OS QNX. From there he finds an official Subaru update, from which he can slowly peel away the layers and deduce the security mechanism. The write-up lays bare his techniques, for example at one point isolating the ARM assembler for a particular function and transplanting it bodily into his own code for investigation.

Eventually he could penetrate the filesystem of the update, and from there he could find that while the root user had a password there were two other accounts that while heavily locked down, had none. The discovery came that files on USB drives plugged into the system were given user-level execute permissions, at which point under the locked-down user he could execute arbitrary code from USB drives. He could then create and modify copies of the device’s filesystem which he could flash onto it, and thus place a modified password validation function into it and gain root access.

Some Hackaday readers will be accomplished in security work such as this, but many of us are hardware specialists for whom it remains something of a dark art. A comprehensive and accessible write-up such as this one is therefore invaluable, because it gives us an insight into the techniques used and perhaps more importantly, into some of the security pitfalls a hardware engineer might unwittingly introduce into their creations.

QNX is a real-time operating system with a long history of appearances in industrial and automotive applications. Readers with long memories may recall their demo floppies from the 1990s which packed a fully functional GUI, Internet connectivity, and modern (for the time) web browser onto a single 1.44Mb floppy disk. We’ve talked about it in the past in a little detail, as when someone made a desktop OS using it.

Add A Host Of 8-Bit Processors To Your Arduino

April 14, 2019 by Jenny List 14 Comments

Normally when we bring you news of a retrocomputing design, it will centre around a single processor. At its heart will be a 6502, a Z80, or perhaps a 6809. There will be a host of support chips, some memory as RAM or ROM, and a bunch of interfaces. [Erturk Kocalar]’s RetroShield project for the Arduino Mega breaks all of those rules, because it supports all three of those classic processors, has no support chips, no memory, and no external interfaces beyond the shield connection to the Mega. What on earth is going on!

A closer look reveals that the project is a set of shields that use the Mega’s power to emulate all the support chips and peripherals you’d have seen on the original hardware. And while it would be impressive to have a single board with support for all three CPUs, in fact there is a PCB for each one. But that makes it no less interesting a project for those with an interest in 8-bit processors, because the focus becomes the software rather than a quest to find out-of-production silicon.

So far there is some limited demo software, and his website goes into some detail on the interfacing and code required. The Arduino can only clock the 8-bit CPU at 95kHz in software which may sound a bit low to those familiar with 1980s home computers, but it’s best to think of this as an experimentation platform and give up dreams of playing Elite. An exciting prospect comes in giving the 8-bit machine access to Arduino shields, if improbable hardware is your bag.

If this has captured your interest, you might also wish to take a look at the $4 Z80 single board computer which has a similar ethos.

Remanufacturing A Rotary Airplane Engine

April 13, 2019 by Jenny List 66 Comments

If someone tells you they have seen a rotary engine, the chances are that you will immediately think of a Wankel engine, as you might find in some of the more exotic Mazda sports cars. But there is another rotary engine that has a prior claim to the name, and it can be found as the power unit for many early-twentieth-century aircraft. In these rotary engines the cylinders are arranged radially around a stationary crankshaft, and it is the engine itself that rotates. They have the advantage of extreme simplicity, smooth power, and a low parts count, at the expense of total loss lubrication, a relatively large rotating mass, and some difficulty in controlling their power. These rotary engines were largely obsolete by the 1920s, but recent upsurge of interest in WW1-era aircraft has led to the creation of a small demand for them. New Zealand based Classic Aero Machining Service have stepped in to fill that gap and are remanufacturing the Gnome radial engine, the most numerous design of that era.

For anyone with an interest in internal combustion engines, the Gnome is a fascinating study. It’s a nine-cylinder design that runs a four-stroke Otto cycle, but instead of the two or more valves you might be familiar with from your motor vehicle it has only a single valve. The so-called Monosoupape design uses its valve for both fuel and exhaust, opening it on the inlet stroke as well as the exhaust stroke. The simplicity of a single valve and no carburetor is thus offset by a difficulty in varying its power , so rotary engines would frequently reduce the number of firing cylinders in lieu of throttling back.

The CAMS Gnome is a faithful copy of the original, but with modern metallurgy and the addition of an electronic ignition system. The original castor oil is still used — it seems classic aviation buffs like the smell — but becuase it is notorious for leaving sticky deposits in the engine they are evaluating modern alternatives. They have some technical details on their website, and there’s a good chance you my hear one of their engines one day at an air show near you.

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It’s (Almost) Two Keytars In One!

April 13, 2019 by Jenny List 4 Comments

All the best retro-1980s chiptune acts should possess a keytar. It’s the Law, or something. [Theremin Hero] has reminded us of this with a new video we’ve shown below featuring an instrument he had a part in creating alongside [Sam Wray] and [Siddharth Vadgama] a few years ago. The Blade is a 3D-printed keytar featuring two Guitar Hero necks and an integrated pair of Game Boys to provide the sound from the authentic silicon.

To describe it in those terms though is to miss a wealth of other components and featured. The keyboard itself is from a Rock Band keytar which feeds MIDI to a Raspberry Pi running PD Extended that handles all the button press mappings. An Arduino Mega performs the same task for the two Guitar Hero necks. Midi from the various sources is processed by an Arduino Boy which then feeds the Game Boys that make the sounds. Oh – and there’s a Leap Motion 3D motion controller in the mix as well, though that doesn’t seem to be used directly in the chiptune synth functionality.

We’ve had a few keytars here over the years, but this one makes us think of the Commodore 64 instrument created by [Jeri Ellsworth].

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