Author: Al Williams

4502 Articles

Silicon Sleuthing: Finding A Ancient Bugfix On The 8086

November 28, 2022 by 31 Comments

Few CPUs have had the long-lasting influence that the 8086 did. It is hard to believe that when your modern desktop computer boots, it probably thinks it is an 8086 from 1978 until some software gooses it into a more modern state. When [Ken] was examining an 8086 die, however, he noticed that part of the die didn’t look like the rest. Turns out, Intel had a bug in the original version of the 8086. In those days you couldn’t patch the microcode. It was more like a PC board — you had to change the layout and make a new one to fix it.

The affected area is the Group Decode ROM. The area is responsible for categorizing instructions based on the type of decoding they require. While it is marked as a ROM, it is more of a programmable logic array. The bug was pretty intense. If an interrupt followed either a MOV SS or POP SS instruction, havoc ensues.

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Create A Compiler Step-By-Step

November 27, 2022 by 19 Comments

While JavaScript might not be the ideal language to write a production compiler, you might enjoy the “Create Your Own Compiler” tutorial that does an annotated walkthrough of “The Super Tiny Compiler” and teaches you the basics of writing a compiler from scratch.

The super tiny compiler itself is about 200 lines of code. The source code is well, over 1,000 but that’s because of the literate programming comments. The fancy title comments are about half as large as the actual compiler.

The compiler’s goal is to take Lisp-style functions and convert them to equivalent C-style function calls. For example: (add 5 (subtract 3 1) would become add(5,subtract(3,1)).

Of course, there are several shortcut methods you could use to do this pretty easily, but the compiler uses a structure like most full-blown modern compilers. There is a parser, an abstract representation phase, and code generation.

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Portable Commodore 64 Lives!

November 27, 2022 by 17 Comments

When you think of a luggable computer, you might think of the old Compaq or — if you are old enough — a Kaypro. But you don’t see as many Commodore SX-64 computers. [The 8-Bit Guy] has wanted one for a while and finally got one, but it wasn’t working. No problem! Just fix it!

The device actually looks sleek compared to some other portables of the era and had a color screen, but — probably due to the price — they didn’t sell very well. The outside of the device looked pretty clean other than some loose screws and clips. The space key was quite yellow but at least there was a keyboard cable which is nearly impossible to find anymore.

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Tesla Coil Makes Sodium Plasma

November 26, 2022 by 11 Comments

Looking for a neat trick to do with your Tesla coil? [The Action Lab] uses his coil to make a metal plasma — in particular, sodium. You can see the results in the video below.

To create a metal plasma, you need a metal vapor and sodium can create a vapor at a relatively low temperature, especially in a vacuum. The resulting glow is pretty to look at, but you will need a bit of lab gear to pull it off.

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Honey, We Shrunk The Nuclear Reactor

November 25, 2022 by 99 Comments

[Power Engineering] took a trip to the Westinghouse facility that provides maintenance for nuclear reactors. The research division there has a new microreactor called eVinci and — according to the company — it is a disruptor. Technically, the device is a heat pipe-based passive cooling design that can generate 5 MW of electricity or 13 MW of heat from a 15 MW heater core. You can see a video about the device below.

The company says its initial targets are remote areas like mines that usually depend on diesel generators. Hundreds of passive heat pipes inside a graphite core which contains TRISO (tristructural isotropic) fuel pellets. The heat pipes allow efficient transfer of thermal energy with no pumps.

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Electroplated 3D Printed Sword: Shiny!

November 24, 2022 by 13 Comments

We all want to 3D print metals, but the equipment to do that is still beyond most home workshops. However, [HEN3DRIK] takes resin 3D-printed items and electroplates them. Might not be as good as printing in metal, but it sure looks metallic. As you can see in the video below, the sword looks like it was crafted from highly-polished steel.

The sword comes out in four pieces. He repeats several times that sanding is the key because you must have flat surfaces. Using sandpaper and steel wool, he worked the parts to a fine finish. The parts assemble along an M8 threaded rod to form a whole. The next step was to electroplate with copper.

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Don’t Believe Everything You Read: The Great Electric Toaster Hoax

November 23, 2022 by 65 Comments

We’ve all looked up things on Wikipedia and, generally, it is usually correct information. However, the fact that anyone can edit it leads to abuse and makes it somewhat unreliable. Case in point? The BBC’s [Marco Silva] has the story of the great online toaster hoax which erroneously identified the inventor of the toaster with great impact.

You should read the original story, but in case you want a synopsis, here goes: Until recently, the Wikipedia entry for toasters stated that a Scottish man named Alan MacMasters invented the electric toaster in the 1800s. Sounds plausible. Even more so because several books had picked it up along with the Scottish government’s Brand Scottland website. At least one school had a day memorializing the inventor and a TV show also honored him with a special dessert named for Alan MacMasters, the supposed inventor. Continue reading “Don’t Believe Everything You Read: The Great Electric Toaster Hoax” →