Hackaday Podcast Episode 321: Learn You Some 3DP, Let The Wookie Win, Or Design A Thinkpad Motherboard Anew

May 16, 2025 by Tom Nardi 3 Comments

Join Hackaday Editors Elliot Williams and Tom Nardi as they take a whirlwind tour of the best and brightest hacks of the last week. This episode starts off with an update about that Soviet Venus lander that’s been buzzing the planet, then moves on to best practices for designing 3D printed parts, giving Chrome OS devices a new lease on life, and a unique display technology that brings a Star Wars prop to life.

You’ll also hear about designing new motherboards for beloved old computers, why you might want to put your calipers on a flatbed scanner, and a NASA science satellite that’s putting in double duty as a wartime reporter. Finally, they’ll cover the interesting physics of meteor burst communications, and the latest developments in the ongoing libogc license kerfuffle.

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.

Continue reading “Hackaday Podcast Episode 321: Learn You Some 3DP, Let The Wookie Win, Or Design A Thinkpad Motherboard Anew” →

This Week In Security: Lingering Spectre, Deep Fakes, And CoreAudio

May 16, 2025 by Jonathan Bennett 5 Comments

Spectre lives. We’ve got two separate pieces of research, each finding new processor primitives that allow Spectre-style memory leaks. Before we dive into the details of the new techniques, let’s quickly remind ourselves what Spectre is. Modern CPUs use a variety of clever tricks to execute code faster, and one of the stumbling blocks is memory latency. When a program reaches a branch in execution, the program will proceed in one of two possible directions, and it’s often a value from memory that determines which branch is taken. Rather than wait for the memory to be fetched, modern CPUs will predict which branch execution will take, and speculatively execute the code down that branch. Once the memory is fetched and the branch is properly evaluated, the speculatively executed code is rewound if the guess was wrong, or made authoritative if the guess was correct. Spectre is the realization that incorrect branch prediction can change the contents of the CPU cache, and those changes can be detected through cache timing measurements. The end result is that arbitrary system memory can be leaked from a low privileged or even sandboxed user process.

In response to Spectre, OS developers and CPU designers have added domain isolation protections, that prevent branch prediction poisoning in an attack process from affecting the branch prediction in the kernel or another process. Training Solo is the clever idea from VUSec that branch prediction poisoning could just be done from within the kernel space, and avoid any domain switching at all. That can be done through cBPF, the classic Berkeley Packet Filter (BPF) kernel VM. By default, all users on a Linux system can run cBPF code, throwing the doors back open for Spectre shenanigans. There’s also an address collision attack where an unrelated branch can be used to train a target branch. Researchers also discovered a pair of CVEs in Intel’s CPUs, where prediction training was broken in specific cases, allowing for a wild 17 kB/sec memory leak.

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Remembering More Memory: XMS And A Real Hack

May 15, 2025 by Al Williams 28 Comments

Last time we talked about how the original PC has a limit of 640 kB for your programs and 1 MB in total. But of course those restrictions chafed. People demanded more memory, and there were workarounds to provide it.

However, the workarounds were made to primarily work with the old 8088 CPU. Expanded memory (EMS) swapped pages of memory into page frames that lived above the 640 kB line (but below 1 MB). The system would work with newer CPUs, but those newer CPUs could already address more memory. That led to new standards, workarounds, and even a classic hack.

XMS

If you had an 80286 or above, you might be better off using extended memory (XMS). This took advantage of the fact that the CPU could address more memory. You didn’t need a special board to load 4MB of RAM into an 80286-based PC. You just couldn’t get to with MSDOS. In particular, the memory above 1 MB was — in theory — inaccessible to real-mode programs like MSDOS.

Well, that’s not strictly true in two cases. One, you’ll see in a minute. The other case is because of the overlapping memory segments on an 8088, or in real mode on later processors. Address FFFF:000F was the top of the 1 MB range.

PCs with more than 20 bits of address space ran into problems since some programs “knew” that memory access above that would wrap around. That is FFFF:0010, on an 8088, is the same as 0000:0000. They would block A20, the 21st address bit, by default. However, you could turn that block off in software, although exactly how that worked varied by the type of motherboard — yet another complication.

XMS allowed MSDOS programs to allocate and free blocks of memory that were above the 1 MB line and map them into that special area above FFFF:0010, the so-called high memory area (HMA). Continue reading “Remembering More Memory: XMS And A Real Hack” →

Remembering Memory: EMS, And TSRs

May 13, 2025 by Al Williams 48 Comments

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

May 12, 2025 by Kristina Panos 4 Comments

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” →

Hackaday Links: May 11, 2025

May 11, 2025 by Dan Maloney 6 Comments

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”

May 10, 2025 by Elliot Williams 10 Comments

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.