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@gloriouscow.bsky.social

220 followers 77 following 650 posts

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

github.com

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gloriouscow.bsky.social @gloriouscow.bsky.social · 2d

I've made some progress decoding the NEC V20 microcode.
I'll be updating this thread on VCF:

forum.vcfed.org/index.php?th...

If you feel like helping out, check out the attached spreadsheet and see if you can identify any of the unidentified source/destination addresses. #retrocomputing #emulation

The NEC V20 Microcode ROM

I commissioned a decap and imaging of the NEC V20 at a sufficient resolution to extract the microcode ROM contents. This was performed by InfoSecDJ A convolutional neural network was used to extrac...

forum.vcfed.org

gloriouscow.bsky.social @gloriouscow.bsky.social · 4d

1000 of these squares were manually categorized as being either a 0 or a 1 bit. These categorized images were then used as a training set for a convolutional neural network, trained with pytorch, that was used to extract the entire bit array.

gloriouscow.bsky.social @gloriouscow.bsky.social · 4d

The image was segmented into individual bit regions using github.com/travisgoodsp... and the bit positions exported to JSON, which was fed into a python script that extracted each bit as a 42x42 pixel square.

GitHub - travisgoodspeed/maskromtool: A CAD tool for extracting bits from Mask ROM photographs.

A CAD tool for extracting bits from Mask ROM photographs. - travisgoodspeed/maskromtool

github.com

gloriouscow.bsky.social @gloriouscow.bsky.social · 4d

The individual bits are encoded via these structures - an opening encodes a 1, the lack of an opening represents a 0.

There are 29K bits in the microcode array.

A zoom of the NEC V20 microcode circuitry showing individually encoded bits

gloriouscow.bsky.social @gloriouscow.bsky.social · 4d

Here's the microcode ROM from the NEC V20.

Cycle accurate V20 emulation? If we can decode it...

#retrocomputing #emulation

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gloriouscow.bsky.social @gloriouscow.bsky.social · 4d

I'd like to shoutout @pcbwayofficial.bsky.social for sponsoring this run of my #ArduinoX86 V4 boards.

The FPU board is my first 4-layer board so I'm hoping I didn't make any fatal mistakes.

#retrocomputing #emulation

Two purple PCBs for the ArduinoX86 project - supporting a 386EX CPU and a 387SX FPU respectively. The boards are laying on a silicon mat on a workbench.

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gloriouscow.bsky.social @gloriouscow.bsky.social · 5d

My talk on #ArduinoX86 from VCF Midwest is up on YouTube!

www.youtube.com/watch?v=m_C7...

#retrocomputing #emulation

Controlling Intel CPUs with Microcontrollers | VCFMW 20 (2025)

YouTube video by VCF Midwest

www.youtube.com

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gloriouscow.bsky.social @gloriouscow.bsky.social · 6d

How about a trade for a functional ibm ps/2 display adapter (the first VGA card)

gloriouscow.bsky.social @gloriouscow.bsky.social · 6d

it's blocking that lovely base PCB you should sell it to me instead lol

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gloriouscow.bsky.social @gloriouscow.bsky.social · 6d

the EGA RAM expansion is pretty rare

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gloriouscow.bsky.social @gloriouscow.bsky.social · 6d

hey @hackadayofficial.bsky.social you have an active phishing campaign going on on hackaday.io

here's the phishing account:
hackaday.io/SupportAlert

Hackaday.io

Hackaday.io is the world's largest collaborative hardware development community.

hackaday.io

gloriouscow.bsky.social @gloriouscow.bsky.social · 6d

you didn't have to

Reposted

Ken Shirriff @righto.com · 7d

We fixed the vintage IBM printer at the Computer History Museum yesterday. Introduced in 1959, the IBM 1403 line printer provided fast, high-quality output, printing 132 character lines. Unfortunately, one column stopped printing, so we disassembled the printer to fix a bad hammer. Keep reading...

The IBM 1403 line printer is a large unit on a stand, printing on green-bar paper that feeds in at the bottom. The printer is dark gray with a clear plastic cover over the printer and a blue panel at the left with a few control buttons. Behind the printer, three 729 tape drives are visible, each about the size of a refrigerator. The IBM 1401 computer is partially visible at the right, about the size of two refrigerators. It has a control panel with lights, switches, and knobs.

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Reposted

Trixter @oldskool.org · 10d

One of the very best write-ups of any demoscene effect I've ever read: cobbpg.github.io/articles/nuf...

Bit-banged multiplexing taken to its extreme.

Patai Gergely

8 bits should be enough for everyone!

cobbpg.github.io

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gloriouscow.bsky.social @gloriouscow.bsky.social · 11d

applesaucefdc.com

applesauce – The Ultimate Floppy Disk Preservation and Analysis Toolkit

applesaucefdc.com

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gloriouscow.bsky.social @gloriouscow.bsky.social · 11d

any man who can hitch the length and breadth of the galaxy, rough it, slum it, struggle against terrible odds, win through, and still knows where his towel is is clearly a man to be reckoned with.

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gloriouscow.bsky.social @gloriouscow.bsky.social · 11d

is that your anti-static towel

gloriouscow.bsky.social @gloriouscow.bsky.social · 13d

I'm honored to have been able to contribute a new pixel-art logo for the excellent Macintosh emulator, Snow.

snowemu.com

#retrocomputing #emulation

The "About" window in the Macintosh emulator, Snow. A pixel-art original Macintosh computer is seen with a smiley face, sitting in a pile of snow.

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gloriouscow.bsky.social @gloriouscow.bsky.social · 15d

Should have called it the Koala Pad

gloriouscow.bsky.social @gloriouscow.bsky.social · 15d

it gives me Teenage Engineering vibes

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gloriouscow.bsky.social @gloriouscow.bsky.social · 16d

100 hours later: you have an instruction decoder

gloriouscow.bsky.social @gloriouscow.bsky.social · 16d

Thanks!

gloriouscow.bsky.social @gloriouscow.bsky.social · 16d

instead of the Rapture it would be more interesting if the Raptor occurred. That's when man eating dinosaurs descend from heaven

gloriouscow.bsky.social @gloriouscow.bsky.social · 16d

Great overview of the V20. A while back I did a technical deep dive into the V20's instruction set and performance vs the 8088.

martypc.blogspot.com/2024/05/expl...

Exploring the NEC V20 CPU

A V20 CPU, courtesy of Konstantin Lanzet ( CC ) The NEC V20 was a 16-bit CPU released in 1984. It is pin-compatible with the Intel 8088 , a...

martypc.blogspot.com

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gloriouscow.bsky.social @gloriouscow.bsky.social · 16d

you wouldn't download a wiener