Tesla’s Dojo Is An Interesting CPU Design

September 6, 2022 by Matthew Carlson 29 Comments

What do you get when you cross a modern super-scalar out-of-order CPU core with more traditional microcontroller aspects such as no virtual memory, no memory cache, and no DDR or PCIe controllers? You get the Tesla Dojo, which Chips and Cheese recently did a deep dive on.

It starts with a comparison to the IBM Cell processors. The Cell of the mid-2000s featured something called the SPE (Synergistic Processing Elements). They were smaller cores focused on vector processing or other specialized types of workloads. They didn’t access the main memory and had to be given tasks by the fully featured CPU. Dojo has 1.25MB of SRAM that it can use as working memory with five ports, but it has no cache or virtual memory. It uses DMA to get the information it needs via a mesh system. The front end pulls RISC-V-like (heavily MIPS-inspired) instructions into a small instruction cache and decodes eight instructions per cycle. Continue reading “Tesla’s Dojo Is An Interesting CPU Design” →

Magnetic Maniac Manages Mangled Memory

September 4, 2022 by Jonathan Bennett 29 Comments

Ahh, floppy disks. Few things carry nostalgia quite like a floppy — either 3 1⁄2 or 5 1⁄4, depending on which generation of hacker you happen to be. (And yes, we hear you grey-beards, 8-inch floppies were definitely a thing.) The real goodies aren’t the floppies themselves, but what they carried, like Wolfenstein 3d, Commander Keen, DOS, or any number of other classics from the past. Unfortunately a bunch of floppy disks these aren’t carrying anything anymore, as bit rot eventually catches up with them. Even worse, on some trashed floppies, a format operation fails, too. Surely, these floppies are destined for the trash, right?
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Coffee With Kernighan

August 24, 2022 by Chris Lott 29 Comments

There was an interesting tidbit buried in a Computerphile video released last week (below the break), featuring professors [David Brailsford] and [Brian Kernighan] having a chat over coffee. Among other topics, they discuss the history and current state of various text processing tools. We learn that [Kernighan] has taken on a summer project of updating the AWK text processing language to handle UTF-8 text, an omission he admits is embarrassing in this day and age. He is also working on a second edition of The AWK Programming Language book, which hasn’t been updated since being first released in 1988.

[Brian Kernighan] is a legend in the world of Unix and computing, working at Bell Labs during the 70s where Unix and C were developed. Among the many accomplishments in his career, he is well-known as the co-author with [Dennis Ritchie] of The C Programming Language, first published in 1972 and still being used decades later, AWK mentioned above, and major updates to troff. More recently, he co-authored The Go Programming Language book in 2015.

If an updated UTF-8-capable AWK interests you, keep an eye on the AWK GitHub repository where [Kernighan] anticipates an update, once he wraps his head around git a little better. We’re happy to see [Brian] so active at 80 years old. If you want to learn more about those early days at Bell Labs, we reviewed [kernighan]’s very interesting UNIX: A History and a Memoir a couple of years ago.

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Recreating DOOM On A Homebrew 8-Bit CPU

August 16, 2022 by Lewin Day 14 Comments

[James Sharman] has been working away on a 8-bit CPU of his own design. Naturally, with his computing device largely functional, the obvious question was asked: can it run DOOM? [James’] latest video explores this question, showing just how close he was able to get.

[James’] 8-bit pipelined CPU also has its own UART, VGA adapter, and sound adapter all built up on discrete components on various PCBs. There’s also a custom interface for a SNES controller as an input device. However, it’s fundamentally well below the specs that DOOM originally required at launch. His 8-bit CPU runs at just 4 MHz, with 64 KB of RAM. This compares poorly to the 32-bit, 33 MHz Intel 386 chips and 4 MB of RAM originally recommended to run the game.

In lieu of running the real thing, [James] demonstrated the limitations of his machine by coding his own demo, nicknamed Doomed. It’s able to average 19 fps video output at a resolution of 80×60, and consists of over 5,000 lines of hand-written assembly code. Fundamentally, it’s a basic 3D engine not dissimilar to Wolfenstein 3D, though without any actual gaming interactions involved.

[James] could have simply stated the machine won’t run DOOM. However, trying to get something similar up and running was a useful learning experience, and in his own words, highly satisfying. This attitude of pushing on in the face of adversity is what propels many other DOOM porting efforts.

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Mac Mini Mini

August 15, 2022 by Matthew Carlson 28 Comments

The Mac Mini has been roughly the same size and shape for 12 years, as the current design was released in June 2010. However, despite being the same general form factor, the internals has shrunk over the years. [Snazzy Labs] took advantage of this to make a miniaturized Mac Mini.

With a donor Mac in hand, they cracked it open and found an oversized power supply, a diminutive logic board, and a good bit of space. Unfortunately, the logic board attaches to a wide IO shield. He removed that, and the fan attached to the heatsink (checking to ensure it still booted). Relocating the WiFi antennas was the trickiest part of the whole build. Given that he wanted to shrink the power supply and the Mac Mini accepts just 12 volts, he devised a clever solution to use MagSafe as a connector. However, Magsafe negotiates over a complex protocol when attached. So, rather than smarten his port up, he dumbed the charger down by replacing it with a Microsoft Surface power supply spliced into the MagSafe connector.

With his mini Mac Mini board ready to go, he began designing a case to fit what was now a single-board computer. A fan of the channel offered a design reminiscent of the 2019 Mac Pro. Unfortunately, FDM printing struggled with the cheese-grater pattern, so [Snazzy Labs] printed it in resin with some mica powder. As a result, the mini mini looks fantastic while taking up just 28% of the volume of the original.

They’ve posted the STL files online with detailed instructions and a parts list if you want to recreate it at home. Perhaps with the smaller motherboard, it might be worth revisiting the Mac Mini inside a PowerBook hack from a few years ago. Video after the break.
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A Portable Computer Living In 1988 But Also In The Future

August 11, 2022 by Matthew Carlson 35 Comments

Every once in a while, there will be a project that is light on details but inundated with glorious, drool-worthy pictures. [Nexaner7] recently showed off his cyberdeck he built over a year inside an old LCD-386. So what’s special about it? This isn’t just a Raspberry Pi or some SBC inside but a complete AMD Ryzen 5600, Nvidia RTX 3060, screen, and keyboard in a 19.5-liter space (0.68 cubic feet). Since there wouldn’t be enough space inside for decent airflow, he decided to water-cool everything, which added to the build.

While [Nexaner7] doesn’t have a video walkthrough, he does have a build log with dozens of pictures in two parts: part 1 and part 2. As you can imagine, there were copious amounts of 3d printing for brackets and holders, trying various screens and GPUs to see what fit and what didn’t. He tried to use the original keyboard, even with a 5-pin DIN to PS2 to USB adapter, but the keyboard was flakey, likely due to rust. He dropped in a CM Quickfire TK PCB with a few modifications as it was close to the same size. He swapped the display for a 1440p portable monitor with a thin ribbon HDMI cable to route from the GPU to the screen.

We’re happy to report that the parts inside were sold to someone who restores old PC, so a somewhat rare LCD-386 wasn’t destroyed. With a gorgeous build like this, perhaps he should enter the Cyberdeck contest. Eagle-eyed readers might notice that recently we covered an LCD-386 with its contents retrieved via a hacked-together serial bus.

PC Hardware Monitor Uses Tricorder-Derived Tech

August 8, 2022 by Tom Nardi 17 Comments

The visually striking hardware monitor that [Mangy_Dog] recently put together for his new custom PC build might look like something out of the Alien franchise, but the hardware he’s built it around actually comes from a very different science-fiction property: Star Trek. Or at least, from a very impressive line of Star Trek props, anyway.

Given the incredible amount of time and effort that [Mangy_Dog] has put into developing his Star Trek: Voyager tricorder, it’s no surprise that he would decide to reuse its graphics chip and microcontroller. But while the familiar hardware might have helped jump-start this build, this was no weekend project.

He’s steadily been working on it for several months now, and even entered it into the 2022 Sci-Fi Contest back in April. Obviously he wasn’t able to complete it before the Contest deadline, but looking at the final results, we’re happy to see he kept chugging away at it.

Of course, with a project like this, the hardware is only half the battle. In the video below, [Mangy_Dog] explains the challenges involved in creating not only the firmware that runs on the monitor, but the accompanying PC-side application. This included modifying existing libraries to add support for the device’s unique flash storage arrangement, and pulling the relevant system status information out of the operating system and into a series of customizable widgets.

As impressive as the project is, [Mangy_Dog] says he’s not done yet. A second revision of the hardware and software will address several issues and add new capabilities, and considering the high degree of polish we’ve come to expect from his creations, we’re not surprised

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