Remembering Memory: EMS, And TSRs

You often hear that Bill Gates once proclaimed, “640 kB is enough for anyone,” but, apparently, that’s a myth — he never said it. On the other hand, early PCs did have that limit, and, at first, that limit was mostly theoretical.

After all, earlier computers often topped out at 64 kB or less, or — if you had some fancy bank switching — maybe 128 kB. It was hard to justify the cost, though. Before long, though, 640 kB became a limit, and the industry found workarounds. Mercifully, the need for these eventually evaporated, but for a number of years, they were a part of configuring and using a PC.

Why 640 kB?

The original IBM PC sported an Intel 8088 processor. This was essentially an 8086 16-bit processor with an 8-bit external data bus. This allowed for cheaper computers, but both chips had a strange memory addressing scheme and could access up to 1 MB of memory.

In fact, the 8088 instructions could only address 64 kB, very much like the old 8080 and Z80 computers. What made things different is that they included a number of 16-bit segment registers. This was almost like bank switching. The 1 MB space could be used 64 kB at a time on 16-byte boundaries.

So a full address was a 16-bit segment and a 16-bit offset. Segment 0x600D, offset 0xF00D would be written as 600D:F00D. Because each segment started 16-bytes after the previous one, 0000:0020, 0001:0010, and 0002:0000 were all the same memory location. Confused? Yeah, you aren’t the only one.

Continue reading “Remembering Memory: EMS, And TSRs”

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The MingKwai Typewriter

Sometimes, a little goes a long way. I believe that’s the case with this tiny media control bar from [likeablob] that uses an ESP32-C3 Super Mini.

An in-line media control bar with four purple-capped key switch buttons and a knob.
Image by [likeablob] via Hackaday.IO
From left to right you’ve got a meta key that allows double functions for all the other keys. The base functions are play/pause, previous track, and next track while the knob handles volume.

And because it uses this Wi-Fi-enabled microcontroller, it can seamlessly integrate with Home Assistant via ESPHome.

What else is under the hood? Four low-profile Cherry MX Browns and a rotary encoder underneath that nicely-printed knob.

If you want to build one of these for yourself, all the files are available on GitHub including the customizable enclosure which [likeablob] designed with OpenSCAD. Continue reading “Keebin’ With Kristina: The One With The MingKwai Typewriter”

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Hackaday Links: May 11, 2025

Did artificial intelligence just jump the shark? Maybe so, and it came from the legal world of all places, with this report of an AI-generated victim impact statement. In an apparent first, the family of an Arizona man killed in a road rage incident in 2021 used AI to bring the victim back to life to testify during the sentencing phase of his killer’s trial. The video was created by the sister and brother-in-law of the 37-year-old victim using old photos and videos, and was quite well done, despite the normal uncanny valley stuff around lip-syncing that seems to be the fatal flaw for every deep-fake video we’ve seen so far. The victim’s beard is also strangely immobile, which we found off-putting.

Continue reading “Hackaday Links: May 11, 2025”

“Man And Machine” Vs “Man Vs Machine”

Every time we end up talking about 3D printers, Al Williams starts off on how bad he is in a machine shop. I’m absolutely sure that he’s exaggerating, but the gist is that he’s much happier to work on stuff in CAD and let the machine take care of the precision and fine physical details. I’m like that too, but with me, it’s the artwork.

I can’t draw to save my life, but once I get it into digital form, I’m pretty good at manipulating images. And then I couldn’t copy that out into the real world, but that’s what the laser cutter is for, right? So the gameplan for this year’s Mother’s Day gift (reminder!) is three-way. I do the physical design, my son does the artwork, we combine them in FreeCAD and then hand it off to the machine. Everyone is playing to their strengths.

So why does it feel a little like cheating to just laser-cut out a present? I’m not honestly sure. My grandfather was a trained architectural draftsman before he let his artistic side run wild and went off to design jewellery. He could draw a nearly perfect circle with nothing more than a pencil, but he also used a French curve set, a pantograph, and a rolling architect’s ruler when they were called for. He had his tools too, and I bet he’d see the equivalence in mine.

People have used tools since the stone age, and the people who master their tools transcend them, and produce work where the “human” shines through despite having traced a curve or having passed the Gcode off to the cutter. If you doubt this, I’ll remind you of the technological feat that is the piano, with which people nonetheless produce music that doesn’t make you think of the hammers or of the tremendous cast metal frame. The tech disappears into the creation.

I’m sure there’s a parable here for our modern use of AI too, but I’ve got a Mother’s Day present to finish.

Supercon 2024: An Immersive Motion Rehabilitation Device

When you’ve had some kind of injury, rehabilitation can be challenging. You often need to be careful about how you’re using the affected parts of your body, as well as pursue careful exercises for repair and restoration of function. It can be tedious and tiring work, for patients and treating practitioners alike.

Juan Diego Zambrano, Abdelrahman Farag, and Ivan Hernandez have been working on new technology to aid those going through this challenging process. Their talk at the 2024 Hackaday Supercon covers an innovative motion monitoring device intended to aid rehabilitation goals in a medical context.

Continue reading “Supercon 2024: An Immersive Motion Rehabilitation Device”

Hackaday Podcast Episode 320: A Lot Of Cool 3D Printing, DIY Penicillin, And An Optical Twofer

This week, Hackaday’s Elliot Williams and Kristina Panos met up across the universe to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous week.

In Hackaday news, the 2025 Pet Hacks Contest rolls on. You have until June 10th to show us what you’ve got, so head over to Hackaday.IO and get started today!

On What’s That Sound, Kristina actually got it this time, although she couldn’t quite muster the correct name for it, however at Hackaday we’ll be calling it the “glassophone” from now on. Congratulations to [disaster_recovered] who fared better and wins a limited edition Hackaday Podcast t-shirt!

After that, it’s on to the hacks and such, beginning with a complete and completely-documented wireless USB autopsy. We take a look at a lovely 3D-printed downspout, some DIY penicillin, and a jellybean iMac that’s hiding a modern PC. Finally, we explore a really cool 3D printing technology, and ask what happened to typing ‘www.’.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Download in DRM-free MP3 and savor at your leisure.

Continue reading “Hackaday Podcast Episode 320: A Lot Of Cool 3D Printing, DIY Penicillin, And An Optical Twofer”

This Week In Security: Encrypted Messaging, NSO’s Judgement, And AI CVE DDoS

Cryptographic messaging has been in the news a lot recently. Like the formal audit of WhatsApp (the actual PDF). And the results are good. There are some minor potential problems that the audit highlights, but they are of questionable real-world impact. The most consequential is how easy it is to add additional members to a group chat. Or to put it another way, there are no cryptographic guarantees associated with adding a new user to a group.

The good news is that WhatsApp groups don’t allow new members to read previous messages. So a user getting added to a group doesn’t reveal historic messages. But a user added without being noticed can snoop on future messages. There’s an obvious question, as to how this is a weakness. Isn’t it redundant, since anyone with the permission to add someone to a group, can already read the messages from that group?

That’s where the lack of cryptography comes in. To put it simply, the WhatsApp servers could add users to groups, even if none of the existing users actually requested the addition. It’s not a vulnerability per se, but definitely a design choice to keep in mind. Keep an eye on the members in your groups, just in case. Continue reading “This Week In Security: Encrypted Messaging, NSO’s Judgement, And AI CVE DDoS”