Robert van Engelen, PhD
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engelen.bsky.social
Robert van Engelen, PhD
@engelen.bsky.social
1.2K followers 730 following 150 posts
Possessed by math and coding since the 80s, vintage tech enthusiast, steam engines fanatic, CEO/CTO of Genivia, fmr Professor of Computer Science and Scientific Computing | NYC | 🇺🇸🇳🇱 | defend democracy | support 🇺🇦 | please be kind to animals🙏
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engelen.bsky.social
Yesterday’s chore: fighting back Entropy by recombining kids Lego pieces back into complete sets to save. But Lego fought back with some brittle brown pieces self-destructing in my hand 💥 So sad 😔
November 12, 2025 at 12:47 PM
engelen.bsky.social
Toshiba HX-10 AA checkup and cleaning. Mechanical Alps keyboard is rock solid and very nice to type on. Having great fun with this industrial-looking beauty. Good to have and use for my ForthMSX development and testing with MegaRam and PicoMSX+. #MSX #Forth
November 9, 2025 at 5:28 PM
engelen.bsky.social
Fixed! RGB output via Scart Looks amazing (compared to composite). A tiny bit of jailbars effect on the blue background, something to fix later perhaps. Likely some other caps that are out of spec.
Sony Hit Bit 75B startup with Sony MSX productivity software showing up on screen, with wedge-shaped MSX machine in front of it. Playing Galaga game with MegaRam cartridge.
November 6, 2025 at 5:27 PM
engelen.bsky.social
Fixing a Sony Hit Bit 75B 1983. Let’s see if this baby works. I suspect it was not turned on for decades, as the 240V UK power cord was cut off. Got that fixed. But before I power this thing on, I want to replace the two crusty filter caps at the 462 and 473 transistor boards above a huge heat sink.
November 5, 2025 at 3:49 AM
Reposted by Robert van Engelen, PhD
delaneykirk.bsky.social
November 2, 2025 at 5:17 PM
engelen.bsky.social
🎃 "Headless Slicer" cuts deep on Halloween nights 😱 Can you guess what it does? Some new retro wizardry Forthcoming! #retro #halloween #msx #forth #compiler #z80
Forth MAIN program to print Happy Halloween :-) show unused bytes free and loop 10 times Compiler with "slicing" optimization to create small headless binaries from Forth source code (without interpreter and with unused words sliced off). Only 1211 bytes binary remains with the Forth internals, runtime, and Forth words to run the compiled program for Halloween. On an MSX1 machine screen, shows the binary hallow.bin program being loaded and run with its output "Happy Halloween" and a smiley (no pumpkin Emoji on MSX alas).
October 31, 2025 at 7:46 PM
engelen.bsky.social
Happy retro Halloween! 🎃
October 31, 2025 at 11:36 AM
Reposted by Robert van Engelen, PhD
moorejh.bsky.social
But does it connect to an Atari or Commodore 8-bit computer? Or maybe a 2-bit computer?
sardonicus.eu Sardonicus @sardonicus.eu · Oct 11
Pantogram’s miniature binary typewriter
spoon-tamago.com/pantograph-i...
tiny typewriter with two keys 0 and 1 the paper in it is covered with 0's and 1's
October 28, 2025 at 2:26 PM
Reposted by Robert van Engelen, PhD
tschak909.bsky.social
I keep trying to tell people about #FujiNet.
That it is a WiFi adapter for your favorite #Atari8bit, #Apple2, #ColecoAdam, #TRS80CoCo, #Commodore, #Atari2600, #AtariLynx, and #MSDOS machines, with more to come.

But word isn't getting out.

Can u help?

fujinet.online
FujiNet - The Future of Retro Computing
The Future of Retro Computing
fujinet.online
October 18, 2025 at 7:17 PM
engelen.bsky.social
Made some progress! Got MSX VDP and VRAM access and control in ForthMSX now working. Playing around with a bit of Forth code to twinkle bitmapped stars live on screen in text mode (picture only below, sorry no GIF). Much faster than BASIC on my Sony MSX2. #MSX #Forth #Z80 github.com/Robert-van-E...
ForthMSX code with comments. >VDP sets a VDP register. VRAM sets the VRAM address in the VDP. >VRAM writes a block of data to the VRAM. VRAM> (not shown) reads a block of data from VRAM. The star word is an array of 4 bitmapped characters that the second loop cycles through to twinkle stars that were drawn by the first loop of random placements of 250 stars. Not animated here, but the live animated stars twinkle at a high frame rate. This is the emulator, because I can't capture my Sony MSX screen.
October 18, 2025 at 8:19 PM
engelen.bsky.social
🎉 ForthMSX is now available as open source on GitHub GitHub.com/Robert-van-E...
engelen.bsky.social Robert van Engelen, PhD @engelen.bsky.social · Sep 22
Having fun coding a new Forth interpreter/compiler in Z80 assembly for the MSX. Making it wicked fast, based on Forth850 that I wrote for the Sharp PC850. MSX Pico+ is a *fantastic* cartridge to get my files over wifi. No AI coding assistance needed, thank you. #MSX #forth
Forth coding and testing the screen editor, displayed on a small monitor using an original MSX2 machine, a Sony Hit Bit F1XD with the fantastic MSX Pico+ to receive my assembled Forth binary files over wifi from a file server I set up.
October 16, 2025 at 8:36 PM
engelen.bsky.social
More fun stuff this weekend with my new Forth system for the MSX. New Forth words for floats using the MSX built-in Math Pack and new Forth file system words using MSX-DOS1. Forth internals are mostly written in assembly for speed. Next up are graphics+sound for game dev. #MSX #Forth #z80 #assembly
MSX emu window showing FORTH loaded with 11K free. then loading "files.fth" to add the FILES word. Executing FILES lists the files on drive A: The ANEW command to load "files.fth" is mine (non standard), which reloads a file with Forth REQUIRE when already loaded and deletes its old definitions. That's useful when updating files to load and test. MSX emu window. Shows loading "primes.fth" with primer generator sieve of Eratosthenes written in Forth. The command line 50 sieve outputs primes up to 50. The line 1000 sieve outputs primes up to 1000 in about 3 seconds. MSX emu window. Loading big-pi.fth to output digits of pi up to 9864 digits. The anew big.pi.fth command loads the program. 152 big-pi outputs the first 152 digits of pi, taking about 50 seconds. 400 big-pi outputs the first 400 digits of pi taking much longer. MSX emu window. Loading Jupiter Ace program CALENDER.FTH to display calendars. The command 2025 October outputs the calendar for the month of October 2025. Likewise, 2025 December outputs the calendar for the month of December 2025. The Jupiter Ace was a Forth 8-bit home computer instead of a BASIC home computer. It was not a success. Jupiter Ace also supports editing and redefining Forth words, which is not a common feature of Forth. Its Forth implementation is not as fast though.
October 12, 2025 at 5:23 PM
Reposted by Robert van Engelen, PhD
sharpworks.bsky.social
#Sharptember A chance find amongst a bunch of tapes I won in an auction turned up something pretty interesting, a compilation tape of games written by Col Needham (the inventor of IMDb) and possibly his master tape from which he sold his mail order games. Here's his game "UFO Attack".
September 28, 2025 at 7:17 PM
engelen.bsky.social
Having fun coding a new Forth interpreter/compiler in Z80 assembly for the MSX. Making it wicked fast, based on Forth850 that I wrote for the Sharp PC850. MSX Pico+ is a *fantastic* cartridge to get my files over wifi. No AI coding assistance needed, thank you. #MSX #forth
Forth coding and testing the screen editor, displayed on a small monitor using an original MSX2 machine, a Sony Hit Bit F1XD with the fantastic MSX Pico+ to receive my assembled Forth binary files over wifi from a file server I set up.
September 22, 2025 at 6:58 PM
Reposted by Robert van Engelen, PhD
ps9714.bsky.social
#RIP Robert Redford.

➡️BREAKING: Robert #Redford, the actor and director who sailed to Hollywood stardom with turns in classics such as “Butch Cassidy and the Sundance Kid” and “All the President’s Men” died Tuesday morning at his home in Utah.

He was 89.
BREAKING: Robert Redford, the actor and director who sailed to Hollywood stardom with turns in classics such as “Butch Cassidy and the Sundance Kid” and “All the President’s Men” and invigorated American independent cinema as one of the founders of the Sundance Film Festival, died Tuesday morning at his home in Utah, the New York Times reported. He was 89. 🔗 : https://nbcnews.to/4nwKBW7
September 16, 2025 at 12:28 PM
engelen.bsky.social
I’ve updated tinylisp in 99 lines of C. Adding color output to Lisp traces in the “extras” version. Also added backquoting/unquoting and some more examples. #lisp github.com/Robert-van-E...
GitHub - Robert-van-Engelen/tinylisp: Lisp in 99 lines of C and how to write one yourself. Includes 21 Lisp primitives, garbage collection and REPL. Includes tail-call optimized versions for speed and...
Lisp in 99 lines of C and how to write one yourself. Includes 21 Lisp primitives, garbage collection and REPL. Includes tail-call optimized versions for speed and reduced memory use. - Robert-van-E...
github.com
August 8, 2025 at 11:38 PM
engelen.bsky.social
Didn’t think it was possible, but Super Mario World runs on MSX2 (Sony HB-F1XD) with MSX Pico+ cartridge. Sound and music with SCC on the audio jack. Brilliant! #MSX
August 8, 2025 at 8:38 PM
Reposted by Robert van Engelen, PhD
instascience.bsky.social
Blue Ghost's view of the moon at 100km altitude.

-Credits: NASA
July 29, 2025 at 7:48 AM
Reposted by Robert van Engelen, PhD
moorejh.bsky.social
Open Circuits is a photographic exploration of the beautiful design inside everyday electronics. Its stunning cross-section photography unlocks a hidden world full of elegance, subtle complexity, and wonder. amzn.to/3H6M1H8 #electronics #photography
Open Circuits: The Inner Beauty of Electronic Components (Packaging may vary)
Open Circuits: The Inner Beauty of Electronic Components (Packaging may vary) [Oskay, Windell, Schlaepfer, Eric] on Amazon.com. *FREE* shipping on qualifying offers. Open Circuits: The Inner Beauty of Electronic Components (Packaging may vary)
amzn.to
July 24, 2025 at 6:48 PM
engelen.bsky.social
Tinylisp in 99 lines of C added an "extras" version with more user-friendly features and runtime optimizations explained in the accompanying article. #lisp github.com/Robert-van-E...
GitHub - Robert-van-Engelen/tinylisp: Lisp in 99 lines of C and how to write one yourself. Includes 21 Lisp primitives, garbage collection and REPL. Includes tail-call optimized versions for speed and...
Lisp in 99 lines of C and how to write one yourself. Includes 21 Lisp primitives, garbage collection and REPL. Includes tail-call optimized versions for speed and reduced memory use. - Robert-van-E...
github.com
July 23, 2025 at 12:43 PM
engelen.bsky.social
Got some lovely new MSX goodies ❤️
Sony Hit Bit F1XDmk2 MSX2 computer with original box. Mostly black with tan floppy drive unit integrated to the right of the machine. Toshiba HX-10AA MSX computer sold on Dutch and Belgium markets (1983 or about). With original box, blue Basic Reference Manual, green Owner’s Manual, cassette tape with 5 example programs. The computer case is black with gray keyboard underlay, off-white keys, and special keys in red, green, blue and dark grey.
July 22, 2025 at 7:37 PM
Reposted by Robert van Engelen, PhD
timeextension.com
Here's Your Third (And Probably Final) Chance To Own A ZX Spectrum Next. (Image: @ZXSpectrumNext) (Repost)
Here's Your Third (And Probably Final) Chance To Own A ZX Spectrum Next
"Mark the date, spread the word far and wide"
www.timeextension.com
June 25, 2025 at 4:50 PM
Reposted by Robert van Engelen, PhD
wonderofscience.bsky.social
Colored droplets in corn syrup seemingly blended together can be returned to their original state by reversing the direction of mixing, a form of laminar flow called "Stokes flow".

Credit: UNM Physics & Astronomy
July 14, 2025 at 11:54 PM
Reposted by Robert van Engelen, PhD
pattonoswalt.bsky.social
“Superman is too woke!”

Literally the first page of the first ever appearance of Superman:
July 11, 2025 at 1:58 PM