@gloriouscow.bsky.social
Developer of MartyPC - a cycle-accurate IBM PC/XT Emulator
https://github.com/dbalsom/martypc
and fluxfox - a PC floppy disk image library
https://github.com/dbalsom/fluxfox
Retro enthusiast and shameless computer geek
https://github.com/dbalsom/martypc
and fluxfox - a PC floppy disk image library
https://github.com/dbalsom/fluxfox
Retro enthusiast and shameless computer geek
more flux cats?
November 10, 2025 at 10:17 PM
more flux cats?
i had an interesting way of getting my drawings into deluxe paint without a scanner - i would sketch stuff on a very thin vellum type paper and tape it to the monitor, and i could follow the lines with the mouse cursor and paint underneath them to trace the artwork onto the screen
November 10, 2025 at 9:57 PM
i had an interesting way of getting my drawings into deluxe paint without a scanner - i would sketch stuff on a very thin vellum type paper and tape it to the monitor, and i could follow the lines with the mouse cursor and paint underneath them to trace the artwork onto the screen
I did work on a few angles of Scar sprites to replace the spider mastermind, he was going to have been behind it all
November 10, 2025 at 9:53 PM
I did work on a few angles of Scar sprites to replace the spider mastermind, he was going to have been behind it all
i wanted to do the wildebeest stampede as a stepped canyon style map that would release a horde of pinkies which I sped up with DeHackEd but the complexity of it with the unmodified DOOM engine meant that I kept getting HOM everywhere and I didn't know how to fix it.
November 10, 2025 at 9:53 PM
i wanted to do the wildebeest stampede as a stepped canyon style map that would release a horde of pinkies which I sped up with DeHackEd but the complexity of it with the unmodified DOOM engine meant that I kept getting HOM everywhere and I didn't know how to fix it.
I had an idea for like the demons invading the pridelands. So it would start out with a map all lush and green with pride rock and then the demons would invade and the next level would be all barren and such.
November 10, 2025 at 9:53 PM
I had an idea for like the demons invading the pridelands. So it would start out with a map all lush and green with pride rock and then the demons would invade and the next level would be all barren and such.
we will put a cute puppy in jail in your place then
November 10, 2025 at 7:39 PM
we will put a cute puppy in jail in your place then
straight to jail
November 10, 2025 at 7:08 PM
straight to jail
nice phong rendering
November 10, 2025 at 2:48 AM
nice phong rendering
It's my hope that this proves to be a valuable resource for the emulation development community.
Someday, I might even have a 386 emulator I can use these to test!
Someday, I might even have a 386 emulator I can use these to test!
November 4, 2025 at 8:21 PM
It's my hope that this proves to be a valuable resource for the emulation development community.
Someday, I might even have a 386 emulator I can use these to test!
Someday, I might even have a 386 emulator I can use these to test!
I've poured easily hundreds of hours into this from developing PCBs, writing the test generator, researching the operation of the 80386, writing my own 386 instruction disassembler, expanding my custom binary test format, debugging, debugging, and debugging more.
(did i mention debugging?)
(did i mention debugging?)
November 4, 2025 at 8:21 PM
I've poured easily hundreds of hours into this from developing PCBs, writing the test generator, researching the operation of the 80386, writing my own 386 instruction disassembler, expanding my custom binary test format, debugging, debugging, and debugging more.
(did i mention debugging?)
(did i mention debugging?)
The test suite includes 941 test files (406 opcodes plus operand size and address size prefix combinations) comprising 1,758,700 individual, heuristically-generated instruction tests, all of them containing cycle exact captures of the execution of a real 386 CPU under the control of an Arduino Giga.
November 4, 2025 at 8:16 PM
The test suite includes 941 test files (406 opcodes plus operand size and address size prefix combinations) comprising 1,758,700 individual, heuristically-generated instruction tests, all of them containing cycle exact captures of the execution of a real 386 CPU under the control of an Arduino Giga.
base VGA supported 350, 400 or 480 lines of resolution. The VGA card told the monitor which was in use by the polarity of the hsync and vsync pulses.
what about 240 you might ask? the 320x200 and 320x240 modes are actually 640x400 and 640x480, just doubled
what about 240 you might ask? the 320x200 and 320x240 modes are actually 640x400 and 640x480, just doubled
November 3, 2025 at 1:13 AM
base VGA supported 350, 400 or 480 lines of resolution. The VGA card told the monitor which was in use by the polarity of the hsync and vsync pulses.
what about 240 you might ask? the 320x200 and 320x240 modes are actually 640x400 and 640x480, just doubled
what about 240 you might ask? the 320x200 and 320x240 modes are actually 640x400 and 640x480, just doubled
i still have these, but they're not sticky anymore
November 3, 2025 at 12:57 AM
i still have these, but they're not sticky anymore
So its interesting to consider, perhaps Psygnosis was in talks with Vault - if not, perhaps they discovered Vault's patent, US4785361A, and realized the technique was patent-encumbered.
November 1, 2025 at 11:08 PM
So its interesting to consider, perhaps Psygnosis was in talks with Vault - if not, perhaps they discovered Vault's patent, US4785361A, and realized the technique was patent-encumbered.
Here's a YouTube video that references it as well.
www.youtube.com/watch?v=K0Xi...
At one point Vault was in talks with 3M to manufacture Prolok disks on a large scale. That ultimately fell through. Prolok disks cost a lot more than what duplicators would charge, so it was an expensive scheme.
www.youtube.com/watch?v=K0Xi...
At one point Vault was in talks with 3M to manufacture Prolok disks on a large scale. That ultimately fell through. Prolok disks cost a lot more than what duplicators would charge, so it was an expensive scheme.
How a Laser-Shot Disk Defeats Hackers & Pirates
YouTube video by Coding Secrets
www.youtube.com
November 1, 2025 at 10:42 PM
Here's a YouTube video that references it as well.
www.youtube.com/watch?v=K0Xi...
At one point Vault was in talks with 3M to manufacture Prolok disks on a large scale. That ultimately fell through. Prolok disks cost a lot more than what duplicators would charge, so it was an expensive scheme.
www.youtube.com/watch?v=K0Xi...
At one point Vault was in talks with 3M to manufacture Prolok disks on a large scale. That ultimately fell through. Prolok disks cost a lot more than what duplicators would charge, so it was an expensive scheme.
Wikipedia references this tweet
web.archive.org/web/20190822...
web.archive.org/web/20190822...
Jon Burton on Twitter
“@mcbpete I think they’re right. I checked and couldn’t find one. It was what I was told was being used by our publisher, Psygnosis, but I guess they swapped approaches. I know for sure it was on the ...
web.archive.org
November 1, 2025 at 10:14 PM
Wikipedia references this tweet
web.archive.org/web/20190822...
web.archive.org/web/20190822...
Makes you wonder if any of the developers of such utilities ever inadvertently blew up their monitor during development.
November 1, 2025 at 9:45 PM
Makes you wonder if any of the developers of such utilities ever inadvertently blew up their monitor during development.
Interestingly, there was a whole ecosystem of CGA card emulators for Hercules graphics cards, and some of them took advantage of this to tweak the 5151's horizontal timings to squeeze out a bit more resolution.
I ran into this developing my emulator and had to allow for a bit of slop in hsync.
I ran into this developing my emulator and had to allow for a bit of slop in hsync.
November 1, 2025 at 9:44 PM
Interestingly, there was a whole ecosystem of CGA card emulators for Hercules graphics cards, and some of them took advantage of this to tweak the 5151's horizontal timings to squeeze out a bit more resolution.
I ran into this developing my emulator and had to allow for a bit of slop in hsync.
I ran into this developing my emulator and had to allow for a bit of slop in hsync.
Technically feasible with certain monitors. The IBM 5151 monitor lacked a horizontal PLL, if you programmed it wildly out of spec, folklore says you could permanently damage it.
Not sure anyone wants to test this out on a surviving example, but it would certainly make an interesting video...
Not sure anyone wants to test this out on a surviving example, but it would certainly make an interesting video...
November 1, 2025 at 9:37 PM
Technically feasible with certain monitors. The IBM 5151 monitor lacked a horizontal PLL, if you programmed it wildly out of spec, folklore says you could permanently damage it.
Not sure anyone wants to test this out on a surviving example, but it would certainly make an interesting video...
Not sure anyone wants to test this out on a surviving example, but it would certainly make an interesting video...
Here's a super closeup zoom of two PROLOK holes on a 5.25" diskette:
This is from a later version of PROLOK, v5 - apparently they decided the solution to the problem of PROLOK getting cracked was MOAR HOLES.
This is from a later version of PROLOK, v5 - apparently they decided the solution to the problem of PROLOK getting cracked was MOAR HOLES.
November 1, 2025 at 9:06 PM
Here's a super closeup zoom of two PROLOK holes on a 5.25" diskette:
This is from a later version of PROLOK, v5 - apparently they decided the solution to the problem of PROLOK getting cracked was MOAR HOLES.
This is from a later version of PROLOK, v5 - apparently they decided the solution to the problem of PROLOK getting cracked was MOAR HOLES.