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Using Greaseweazle to make bootable DOS disks

Using Greaseweazle to make bootable DOS disks

Have written previously about my experiments with the very excellent Greaseweazle; but that was reading things like my old Kings Quest 5.25″ floppy disks from my modern 12th Gen Intel PC running Windows 10.

Recently I acquired some old pc hardware and put together a retro 486-DX pc. To that end, I needed to create a DOS boot disk for this old system. That meant I needed to write a 1.2mb DOS boot disk.

Previously I used some boot disk images to create an old DOS virtual machine running Windows 1.0. For that, I used a bunch of archived boot disks images from WinWorld archive.

But how do I write these little beasts?

I floundered around with greaseweezle’s command line but this guide from Tech Tangents really helped out. There’s clearly a lot more I need to learn, but this got me a bootable 5.25″ 1.2mb floppy disk. I was able to test it on 2 different drives, and both worked. So, that’s pretty sweet!

Greaseweezle command line samples

How to write DOS 6.22 image to a 5.25″ 1.2m floppy drive attached to the ribbon cable right before the cable twist:

gw write --drive b --format ibm.1200 Dos6.22-5.25.img

To write a DOS 3.30 image to a 5.25″ 360k floppy drive attached to the ribbon cable right before the twist:

gw write --drive b --format ibm.360 DOS330-360k.img
Realtime Human ‘tele-operation’

Realtime Human ‘tele-operation’

Carnegie Mellon researchers have developed a real-time human tele-operation system. Using a simple camera, it is able to read the actions of a human person and then translate that into real-time full-body control of a robot.

Individuals can now seamlessly teleoperate full-sized humanoids to execute a myriad of actions. According to researchers, they can perform simple tasks like picking and placing objects to dynamic movements like walking, kicking, and even boxing.

Read the paper here:

There’s lots of possibilities for this kind of remotely operated humanoid robotic system. Remotely controlled humanoid robots could save countless lives operating in dangerous environments.

They could be used to go in and shut down equipment after dangerous chemical or industrial accidents. Search dangerous buildings for survivors after earthquakes. They could perform dangerous police or urban warfare operations without loss of life. Stop terrorist by defusing bombs. Another such place would be effecting repairs, shutdowns, and cleanup in highly radiated areas like Chernobyl, Fukushima, or when there are nuclear accidents. In the future, we may never need the horrors of Chernobyl’s biorobots to deal with such disasters.


Blue-screen Windows on purpose

Blue-screen Windows on purpose

I wrote awhile back on how to crash Linux/cause a Linux kernel panic in order to test how your program can handle a crash – but can you cause a Windows blue-screen programmatically?

Raymond Chen of the New Old Thing describes a variety of methods to crash Windows purposefully. He also cautions against ad-hoc methods like killing winlogin.

Methods you can use to cause a Windows Blue-screen:

  1. Windows allows you to configure a specific keyboard combination to cause a crash. You set some registry keys and then can crash a system by holding right CTRL then pressing scroll lock key twice. You can also customize the key sequence via registering custom keyboard scan codes. If you have a kernel debugger attached it will trigger the kernel debugger after the crash dump is written.
  2. The best way to trigger an artificial kernel crash is to use NotMyFault, which is part of the Microsoft Windows SysInternals tools.
nVidia’s CPU stacks up respectably against the AMD Threadripper 7980X

nVidia’s CPU stacks up respectably against the AMD Threadripper 7980X

More eyes are nVidia’s GH200 Grace Superchip. The GH200 Superchip is the combination of a Grace CPU and a Hopper-based H200 GPU. While the results aren’t definitive, they should raise eyebrows.

In 39 individual Linux-based benchmark tests, Grace (the CPU side) beat the AMD Threadripper 7980X in 17 tests and the 7995WX in 15. It even stacks up well against Intel Sapphire Rapids.

Sapphire Rapids and Threadripper enjoy many advantages. Far more apps are optimized for x86 than for Arm. Threadripper has much more aggressive clock speeds than the efficiency-focused Grace chip and far more L3 cache (7980X has more than double, and the 7995WX more than triple).

But raw performance may not be the only consideration. There is speculation that Grace Hopper is more energy efficient – but there is no real data on TDP outside the whole package requirement of 500w. Also, for tasks that are more GPU bound than CPU bound, the combination may provide higher effective processing power than a faster CPU paired with a discrete GPU. Time will tell.

It shows that nVidia’s Grace entry is not to be ignored. Paired with the Hopper GPUs, it might offer a very viable alternative to x86 stacks – if your software can run on Arm.


Reconstructing a binary GameBoy game just from the sound of it dying

Reconstructing a binary GameBoy game just from the sound of it dying

ZZAZZGlitch has successfully reverse-engineered a Game Boy Advance game’s data solely from the sound made when a GBA game experiences a hard crash. The per-game crash ‘songs’ that happen when a GBA game crashes actually contains the entire cartridge’s ROM data and every sound in the game played back in raw audio in sequential order. In theory, with the correct tools and know-how, any GBA game should be recoverable from recording that audio.

ZZAZZGlitch shows us how in his video. Wow. He even made the source code is available on his personal site, labeled “”. It still took a LOT of hacking and manual fix-ups; but he got a bootable game in the end.

Reminds me of the guy that tried to reconstruct the Yars Revenge source from the explosions shown onscreen.

Demo scenes are not dead

Demo scenes are not dead

Massive in the 90’s, Demoscenes are not dead. Revision 2024 demo party just took place March 29th to April 1st in Saarbrücken Germany.

There was music, seminars, videos, livestreams, a 5k run, and of course – amazing code demos. This included some competing 256-byte demos here. One of the best was a post-apocalyptic black-and-white city created with just 256 bytes of Gopher code running on DOS.

Don’t pay for a VPN, make your own

Don’t pay for a VPN, make your own

There’s been some trouble lately in which free VPN services have been collecting and selling your data. Others have had major leaks or hacks (such as the new TunnelVision attack). So why not set up your own VPN and avoid those issues?

A few important reminders. VPN’s do not make you anonymous. They only create a secure pipe between you and that server. From that point on, your traffic can be collected and used – and many free VPN services do exactly that. Anonymity comes only if you use things like the TOR network.

But instead of paying a VPN service fee or potentially having your data collected and sold, you might set up your own VPN server on a Rasberry Pi.

  1. Create an account on a cloud hosting provider like DigitalOcean
  2. Download Algo VPN on your local computer, unzip it
  3. Install the dependencies with the command lines on this page
  4. Run the installation wizard
  5. Double click on the configuration profiles in the configs directory

It’s important to note that there are some limitations. This setup is good if you need a secure connection from where you are to the location of the server (ex: You’re in China and need access to US services that are blocked). Again, this doesn’t make you anonymous as your data exits the VPN and becomes public again.

Paid VPN services also often offer servers in different countries so you can spoof being in specific countries. This will not do that unless you have paid for hosting in those countries.


DREM – MFM/RLL hard drive and Floppy emulators

DREM – MFM/RLL hard drive and Floppy emulators

Connecting old floppy disk drives to modern hardware is not easy. Resurrecting old MFM and RLL hard drives is even harder. The primary method would simply be to get an old PC with the legacy hardware to read the hard drives. But now there’s a few soltuions.


DREM is based on the high performance FPGA platform and does not require the use of a PC for any file encoding operations. DREM is equipped with an VGA output, PS/2 keyboard input and file manager software. A user can browse the SD card and insert DSK images into virtual drives.

DREM uses DSK disk image files, which contain the raw dump of a disk. The raw image consists of a sector-by-sector binary copy of the source medium.

If you’re just looking for floppy emulation, I recommend GreaseWeazle or other solutions.

MFM Board Emulator:

Also available, but doesn’t seem quite as well baked, is the pdp8online MFM board emulator.

Holodeck flooring

Holodeck flooring

Lanny Smoot is a Disney Research Fellow that is being inducted into the National Inventors Hall of Fame.

Here he is showing off his holo-tile floor that allows multiple people to walk on it in any direction and it automatically keeps you centered on the floor. Definitely something that could be used for VR.