computer hacks

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computer hacks

A NOR Gate For An ALU?

April 5, 2023 by 18 Comments

If you know anything about he design of a CPU, you’ll probably be able to identify that a critical component of all CPUs is the Arithmetic Logic Unit, or ALU. This is a collection of gates that can do a selection of binary operations, and which depending on the capabilities of the computer, can be a complex component. It’s a surprise then to find that a working CPU can be made with just a single NOR gate — which is what is at the heart of [Dennis Kuschel]’s My4th single board discrete logic computer. It’s the latest in a series of machines from him using the NOR ALU technique, and it replaces hardware complexity with extra software to perform complex operations.

Aside from a refreshingly simple and understandable circuit, it has 32k of RAM and a 32k EPROM, of which about 9k is microcode and the rest program. It’s called My4th because it has a Forth interpreter on board, and it has I2C and digital I/O as well as a serial port for its console.

This will never be a fast computer, but the fact that it computes at all is ts charm. In 2023 there are very few machines about that can be understood in their entirety, so this one is rather special even if it’s not the first 1-bit ALU we’ve seen.

Thanks [Ken Boak] for the tip.

Picture of the PCIce card with a fan attached

Server Network Cards Made Extra Cool

April 3, 2023 by 25 Comments

Using cheap and powerful server expansion cards in your desktop builds is a tempting option for many hackers. Of course, they don’t always fit mechanically or work perfectly; for instance, some server-purpose cards are designed for intense amounts of cooling that servers come with, and will overheat inside a relatively calm desktop case. Having encountered such a network card, [Chris] has developed and brought us the PCIce – a PCIe card that’s a holder and a controller for a 80mm fan.

The card gets fan 12V from the PCIe slot, and there’s an ATTiny to control the fan’s speed, letting you cycle through speeds with a single button press and displaying the current speed through LEDs. There’s a great amount of polish put into this card – from making it mechanically feature-complete with all the fancy fasteners, to longevity-oriented firmware that even makes sure to notice if the EEPROM-stored settings ever get corrupted. At the moment, the schematics and the ATTiny firmware are open-source, [Chris] has promised to publish hardware files after polishing them, and has also manufactured a batch of PCIce cards for sale.

When it comes to making use of cheap server-purpose cards, a cooling solution is good to see – we’ve generally seen adapters from proprietary form-factors, like this FlexLOM adapter from [TobleMiner] to make use of cheap high-throughput network cards with slightly differing mechanical dimensions and pinouts. Every batch of decommissioned server cards has some potential with only a slight hitch or two, and it’s reassuring to see hackers make their eBay finds really work for them.

8086 Multiply Algorithm Gets Reverse Engineered

March 16, 2023 by 10 Comments

The 8086 has been around since 1978, so it’s pretty well understood. As the namesake of the prevalent x86 architecture, it’s often studied by those looking to learn more about microprocessors in general. To this end, [Ken Shirriff] set about reverse engineering the 8086’s multiplication algorithm.

[Ken]’s efforts were achieved by using die photos of the 8086 chip. Taken under a microscope, they can be used to map out the various functional blocks of the microprocessor. The multiplication algorithm can be nutted out by looking at the arithmetic/logic unit, or ALU. However, it’s also important to understand the role that microcode plays, too. Even as far back as 1978, designers were using microcode to simplify the control logic used in microprocessors.

[Ken] breaks down his investigation into manageable chunks, exploring how the chip achieves both 8-bit and 16-bit multiplication in detail. He covers how the numbers make their way through various instructions and registers to come out with the right result in the end.

It’s a fun look at what’s going on at the ground level in a chip that’s been around since before the personal computer revolution. For any budding chip designers, it’s a great academic exercise to follow along at home. If you’ve been doing your own digging deep into CPU architectures, don’t hesitate to drop us a line!

Wooden ITX PC Case Smacks Of Sophistication

March 16, 2023 by 15 Comments

Computer cases have come a long way from the ugly beige boxes of the early 2000s. Still, if it was going to sit on his desk, [MXC Builds] wanted something with a little more class. His custom Ironbark ITX PC seems to fit the aesthetic nicely.

The case’s outer shell is ironbark wood cut at 45 degrees and joined for a beautiful waterfall edge (the wood grain seems to flow uninterrupted). The power supply was heavily modified to take a thinner but larger fan, and a new cover and intake grill were 3D printed. As there were no mounting holes on the bottom of the power supply, he printed a bracket with spring clips to hold the PSU securely. Next, he routed a PCI riser cable to the other side of the internal panel so the GPU could mount on the back. He cut custom cables to match up the lengths needed for every run. Finally, rather than placing the power button on the front or top, it was on the side in a custom bracket.

It’s an absolutely gorgeous build that packs some respectable hardware in a tiny space (7.9 L or ~482 in3). The use of 3D printed parts and careful planning results in an incredibly tidy computer that most would proudly display on their desk. It is an open-air case, and if you’re looking for something a little more enclosed, perhaps this mid-century PC might whet your appetite.

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Raspberry Pi Adds Second Laptop Monitor

March 15, 2023 by 17 Comments

If you have a cheap laptop and you realize you can’t connect a second monitor to it, what do you do? Well, if you are [Pierre Couy], you grab a Raspberry Pi and put together a virtual screen solution.

Like all good projects, this one started with some goals and requirements:

  • Low latency
  • Redable text
  • At least 10 frames per second
  • Fast catch up if the remote screen falls behind
  • Low-bitrate encoding; no hardware acceleration
  • A DHCP server on the Pi to manage the network
  • Power control for the attached monitor

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Sixteen wires of various colors are attached in pairs to record the electrical activity of split gill fungi (Schizophyllum commune) on a mossy, wooden stick. photo by Irina Petrova Adamatzky

Unconventional Computing Laboratory Grows Its Own Electronics

March 15, 2023 by 6 Comments

While some might say we’re living in a cyberpunk future already, one technology that’s conspicuously absent is wetware. The Unconventional Computing Laboratory is working to change that.

Previous work with slime molds has shown useful for spatial and network optimization, but mycelial networks add the feature of electrical spikes similar to those found in neurons, opening up the possibility of digital computing applications. While the work is still in its early stages, the researchers have already shown how to create logic gates with these fantastic fungi.

Long-term, lead researcher [Andrew Adamatzky] says, “We can say I’m planning to make a brain from mushrooms.” That goal is quite awhile away, but using wetware to build low power, self-repairing fungi devices of lower complexity seems like it might not be too far away. We think this might be applicable to environmental sensing applications since biological systems are likely to be sensitive to many of the same contaminants we humans care about.

We’ve seen a other efforts in myceliotronics, including biodegradable PCB substrates and attempts to send sensor signals through a mycelial network.

Via Tom’s Hardware.

PCIe For Hackers: The Diffpair Prelude

March 14, 2023 by 35 Comments

PCIe, also known as PCI-Express, is a highly powerful interface. So let’s see what it takes to hack on something that powerful. PCIe is be a bit intimidating at first, however it is reasonably simple to start building PCIe stuff, and the interface is quite resilient for hobbyist-level technology. There will come a time when we want to use a PCIe chip in our designs, or perhaps, make use of the PCIe connection available on a certain Compute Module, and it’s good to make sure that we’re ready for that.

PCIe is everywhere now. Every modern computer has a bunch of PCIe devices performing crucial functions, and even iPhones use PCIe internally to connect the CPU with the flash and WiFi chips. You can get all kinds of PCIe devices: Ethernet controllers, high-throughput WiFi cards, graphics, and all the cheap NVMe drives that gladly provide you with heaps of storage when connected over PCIe. If you’re hacking on a laptop or a single-board computer and you’d like to add a PCIe device, you can get some PCIe from one of the PCIe-carrying sockets, or just tap into an existing PCIe link if there’s no socket to connect to. It’s been two decades since we’ve started getting PCIe devices – now, PCIe is on its 5.0 revision, and it’s clear that it’s here to stay.

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