Building MS-DOS From Scratch Like It’s 1983

Building a complete operating system by compiling its source code is not something for the faint-hearted; a modern Linux or BSD distribution contains thousands of packages with millions of lines of code, all of which need to be processed in the right order and the result stored in the proper place. For all but the most hardcore Gentoo devotees, it’s way easier to get pre-compiled binaries, but obviously someone must have run the entire compilation process at some point.

What’s true for modern OSes also holds for ancient software such as MS-DOS. When Microsoft released the source code for several DOS versions a couple of years ago, many people pored over the code to look for weird comments and undocumented features, but few actually tried to compile the whole package. But [Michal Necasek] over at the OS/2 Museum didn’t shy away from that challenge, and documented the entirely-not-straightforward process of compiling DOS 2.11 from source.

The first problem was figuring out which version had been made available: although the Computer History Museum labelled the package simply as “MS-DOS 2.0”, it actually contained a mix of OEM binaries from version 2.0, source code from version 2.11 and some other stuff left from the development process. The OEM binaries are mostly finished executables, but also contain basic source code for some system components, allowing computer manufacturers to tailor those components to their specific hardware platform.

Compiling the source code was not trivial either. [Michal] was determined to use period-correct tools and examined the behaviour of about a dozen versions of MASM, the assembler likely to have been used by Microsoft in the early 1980s. As it turned out, version 1.25 from 1983 produced code that most closely matched the object code found in existing binaries, and even then some pieces of source code required slight modifications to build correctly. [Michal]’s blog post also goes into extensive detail on the subtle differences between Microsoft-style and IBM-style DOS, which go deeper than just the names of system files (MSDOS.SYS versus IBMDOS.COM).

The end result of this exercise is a modified DOS 2.11 source package that actually compiles to a working set of binaries, unlike the original. And although this does not generate any new code, since binaries of DOS 2.11 have long been available, it does provide a fascinating look into software development practices in an age when even the basic components of the PC platform were not fully standardized. And don’t forget that even today some people still like to develop new DOS software.

Is Cloud Seeding Good, Bad, Or Ugly?

The Chinese Communist Party celebrated its centenary on the 1st of July, 2021. For such a celebration, clear skies and clean air would be ideal. For the capable nation-state, however, one needn’t hope against the whims of the weather. One can simply control it instead!

A recent paper released by Tsinghua University indicated that China had used cloud seeding in order to help create nicer conditions for its 100-year celebration. Weather modification techniques have been the source of some controversy, so let’s explore how they work and precisely what it was that China pulled off.

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An All In One Cube PC For A 1990s That Never Quite Happened

When a particular device or appliance is evoked, there comes with it a set of expectations over what it might look like. A toaster, a camera, a washing machine, or a PC, will all have their own accepted form factors, and it’s rare that a manufacturer is adventurous enough to venture outside them. In the world of PCs there was a brief flowering of this type of creativity through the 1990s, and it’s that time which [ikeji]’s cube PC squarely fits in. It’s a 3D printed PC with a built-in display, keyboard, and printer, and while some might categorize it as a cyberdeck we’d say it goes further, we could easily imagine a slightly more polished version being an object of desire back when a powerful machine carried an 80486.

Inside it’s no slouch, packing an AMD Ryzen 7 Pro on a Mini-ITX motherboard, and while the display is a mere 7-incher it fits neatly behind the fold-down keyboard. The thermal printer is maybe more of a toy, but it’s good to find that even a bleeding-edge motherboard still has a serial port on it somewhere that it can talk to.

While the build undoubtedly has a few home-built rough edges we like the idea, echoing as it does those all-in-ones from the CRT era. Unless you have a handy Minitel terminal you won’t find much like it.

A Particularly Festive Chip Decapping

As we approach the moment in the year at which websites enter a festive silly season of scrambling to find any story with a festive angle, we’re pleased to see the ever-reliable [Ken Shirriff] has brought his own take on Christmas tech to the table with a decapping of the UM66T melody chip that has graced so many musical greeting cards.

The surprise in this age of ubiquitous microcontrollers is that this is not a smart device; instead it’s a single-purpose logic chip whose purpose is to step through a small ROM containing note values and durations, driving a frequency generator to produce the notes themselves. The frequency generator isn’t the divider chain from the RC oscillator that we might expect, instead it’s a shift register arrangement which saves on the transistor count.

Although the UM66 is a three-pin device, there are a few other pins on the die. These are likely to be for testing. As a 30+ year old product its design may be outdated in 2021, but it’s one of those chips that has survived without being superseded because it does its task without the need for improvement. So when you open a card and hear the tinny tones of a piezo speaker this holiday season, spare a thought for the ingenuity of the design behind the chip that makes it all possible.

A wooden device with an LED display and speakers

The Inspirer Keeps Your Mood Up With Inspirational Quotes And Soothing Music

While some people enjoy the cold weather and long, dark nights in the Northern Hemisphere these days, others may find it hard to keep a positive mindset all through the winter. [Michael Wessel] decided he needed to do something about that and came up with The Inspirer, a desktop display that shows inspirational quotes and plays soothing music.

The design is deliberately bare-bones: a strip of wood, standing upright thanks to two metal brackets, onto which a bunch of components have been screwed, glued and taped. The actual display consists of a row of 14-segment LED modules that can show basic alphanumeric characters; these displays emit white light, but [Michael] added a red color filter in front to give them a more “retro” look.

This device is fully off-grid, so no Internet connection issues will disrupt your flow. A huge database of quotes and a selection of music tracks are stored on a pair of micro SD cards; an MP3 player module handles the music while an Arduino picks a quote, drives the display, and reads the buttons. You can select quotes based on a certain theme: examples include friendship, gardening, money, and love. But if you’re open to anything, you can just set it to “random” and get something from any of the 120 categories.

[Michael]’s simple and straightforward design should hopefully prove inspirational to many hardware enthusiasts. But if you’re looking for something more advanced, we featured a neat pomodoro timer that displays quotes a few weeks ago. Of course, this being Hackaday, we’ve also seen a clock based on literary quotes.

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Hackaday Links: December 19, 2021

Key fobs as a service? Have we really gotten to that point? It would seem so, at least for Toyota, which is now requiring a subscription to use the company’s Remote Connect function. To be fair to Toyota, the Remote Connect system seems to do a bit more than the average key fob, with things like remote start and smartphone or smartwatch integration. It doesn’t appear that using the key fob for more mundane uses, like opening the doors, will be nerfed by this change. But if you want to warm up your car on a cold winter’s morn while you’re still in your jammies, then be prepared to cough up $8 a month or $80 a year on select 2018 and above models. Whether Toyota and other manufacturers get away with this nickel-and-dime stuff is up to the buyers, of course; if enough people opt out, maybe they’ll think of some other way to pad their bottom line. But since we’ve already seen heated seats as a service (last item), we suspect this is the shape of things to come, and that it will spread well beyond the car industry.

Speaking of cars, if you thought the chip shortage was over just because car dealer lots are filling back up, think again. Steve over at Big Mess o’ Wires reports that he’s having trouble sourcing chips for his vintage computer accessories. He includes a screenshot from Digi-Key showing zero stock on ATmega1284s. He also reports that the Lattice FPGA he uses for his Yellowstone universal disc controller is now unobtainium, where it had previously been easily sourced for about $5. He also has a pointed warning about some suppliers making it look like they have stock, only to send a “whoopsie” email after charging your credit card, or worse, telling you the price has increased over 400%. We suppose this was inevitable; there’s only so much fab capacity in the world, so eventually the fabs will switch over to producing whatever they can get paid the most for. And since car manufacturers have a lot more clout with suppliers than just about anyone else, it’s only natural for the shortages to shift down-market like this.

Do we finally have a “go” on James Webb? Maybe. The launch of the space telescope was originally scheduled for December 18 — well, OK, originally it was supposed to be in space in 2007, but let’s not go there — but a problem with a clamp caused unexpected vibrations in the $10 billion space observatory, resulting in inspections that pushed the launch back to the 22nd. That lasted for about a week, until the fueled and packaged spacecraft stopped sending data to launch controllers. The problem ended up being entirely relatable — a bad data cable — but resulted in the loss of two more days. JWST is now set to launch on Christmas Eve at 7:20 AM Eastern Standard Time, pending a readiness review on Tuesday morning. Fingers crossed that the long-awaited observatory has a safe 30-day trip to Lagrange point L2.

And finally, breathless tech journalists couldn’t wait to report this week that the world’s first warp bubble had been created. The paper was published by Dr. Harold “Sonny” White et al from the Limitless Space Institute, and claims to have discovered a “micro/nano-scale structure” that “predicts negative energy density distribution that closely matches requirements for the Alcubierre metric.” That last bit, the one about the Alcubierre metric, refers to the Alcubierre drive, which proposed a way to warp space-time and drive a ship at arbitrarily high speeds. But did this team actually create a warp bubble? It doesn’t seem so, at least according to one article we read. There’s also the problem of Dr. White’s previous claims of breaking the laws of physics with a reactionless EM drive. Scientific quibbling aside, there’s a sure-fire way of telling that no warp bubble was created — if there had been one, this would have happened.