Robert van Engelen, PhD

I’ve written code with SWI-Prolog since 1994, so it’s certainly over 30 years. Jan came over to our Uni when I had invited him to give a talk. Glad he also added multi-precision integers later, like I added myself using the GNU MP lib, stored as atoms. The foreign interface was very useful.

SWI-Prolog is excellent. The author, Jan Wielemaker, keeps expanding it to a does-it-all Prolog platform.

The author admits in the article that numerical weather forecast models are still needed. Numerical models use physics (PDE math etc). But AI is a black box, trained with historical data to extrapolate a prediction. AI is not robust and will make mistakes when measurements do not align with history.

Inside the Best Weather-Forecasting AI in the World Autonomous weather balloons surf the winds to collect needed data

Weather balloons are largely unnecessary. We have excellent weather models that are fed land-based data and sea-based data. So I’m so disappointed in IEEE to publish this unscientific article claiming that AI and weather balloons are better. spectrum.ieee.org/amp/ai-weath...

💔

Naïve implementation that runs in quadratic time, so won’t scale. Instead of that, use a sliding window and update the sum incrementally (subtract outgoing, add incoming). Use C++ for speed.

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 😔

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

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.

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.

Addicted? Nah. Just always close to grab, like these on our counter right now.

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).

🎃 "Headless Slicer" cuts deep on Halloween nights 😱 Can you guess what it does? Some new retro wizardry Forthcoming! #retro #halloween #msx #forth #compiler #z80

Happy retro Halloween! 🎃

But does it connect to an Atari or Commodore 8-bit computer? Or maybe a 2-bit computer?

FujiNet - The Future of Retro Computing The Future of Retro Computing

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

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...

Philips MSX New Media System

🎉 ForthMSX is now available as open source on GitHub GitHub.com/Robert-van-E...

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.

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

-1 1 RSHIFT . since RSHIFT is a logical shift, not arithmetic, it shifts in a 0 so to get max positive value of a signed integer. Minor caveat: Assumes 2s complement, but which is universal these days.

#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".

Hope this helps: I wrote a Forth introduction and manual for newbies to Forth, for a 2012 standard Forth implementation which is more up to date than the vintage textbook introductions github.com/Robert-van-E...

Combinations of words are included for performance, such as 1+ 2* 2/ 0= to perform two sequential operations with one word, but there are also a few to perform two operations simultaneously like /MOD (div mod) to return two results. Because most vintage Forth do not optimize code, these are useful.

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.

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

Learnt Pascal on one of these at home. Swapping disks all the time, because editing, compiling/assembling and running all required swapping disks. Now that’s how you learn to write correct code the first time!

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

#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.

Maybe, if they made them not so ugly 😒

Curiously, Z-80 isn’t typically spelled that way. Nice find for your collection!

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...

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...