A repository of bug-fixed and patched software projects for DEC PDP-11 systems, targeting real hardware, SimH, and PiDP-11 emulators running RT-11 and RSX-11M-PLUS. The two main projects are FIG-FORTH v1.4, which corrects garbled terminal output and a corrupted screen file, and FOCAL-11 V11-01C, which fixes an infinite recursion crash in the FEXP function.
- FIG-FORTH originally marked dictionary names with a high bit that modern terminals rendered as a literal "?" character; the patch strips it before display without affecting the dictionary
- The FORTH.DAT file was distributed with a VARIABLE RMS record format, embedding 2-byte length headers every 512 bytes that appeared as stray characters in screens
- FOCAL-11's XFEXP computed e^x by recursively halving the exponent until it fell below -8, but zero's exponent never decreases, so the recursion ran the stack into memory; all other math functions already had a depth guard
- FOCAL is a BASIC-like language from the late 1960s; Lunar Lander was originally written in it
- FIG-FORTH originally marked dictionary names with a high bit that modern terminals rendered as a literal "?" character; the patch strips it before display without affecting the dictionary
- The FORTH.DAT file was distributed with a VARIABLE RMS record format, embedding 2-byte length headers every 512 bytes that appeared as stray characters in screens
- FOCAL-11's XFEXP computed e^x by recursively halving the exponent until it fell below -8, but zero's exponent never decreases, so the recursion ran the stack into memory; all other math functions already had a depth guard
- FOCAL is a BASIC-like language from the late 1960s; Lunar Lander was originally written in it
Jeff Shrager's repository introduces "executable archaeology" — the practice of recovering, transcribing, and running the original historical source of early computing programs so that the surviving artifact itself, rather than a modern rewrite, can serve as experimental evidence. The main project here is an IPL-V reimplementation of Victor Yngve's 1959–61 MIT sentence generator, run under Herbert A. Simon's account on 25 June 1962, whose surviving printout preserves the program, its phrase-structure grammar, execution traces, and handwritten corrections by Simon and his daughter Katherine.
- The repository also points to separate repos reconstructing the Logic Theorist in two historically distinct forms (LT1 in IPL-I and LT5 in IPL-V) and a full CTSS/IBM 7094 reanimation of Weizenbaum's original ELIZA
- A 2026 arXiv paper by Shrager and a 2025 IEEE Annals paper by Lane et al. provide the formal background
- Six stated principles govern the work, including distinguishing original behavior from behavior introduced by the reconstruction
- The repository also points to separate repos reconstructing the Logic Theorist in two historically distinct forms (LT1 in IPL-I and LT5 in IPL-V) and a full CTSS/IBM 7094 reanimation of Weizenbaum's original ELIZA
- A 2026 arXiv paper by Shrager and a 2025 IEEE Annals paper by Lane et al. provide the formal background
- Six stated principles govern the work, including distinguishing original behavior from behavior introduced by the reconstruction
Pascal Costanza traces the historical evolution of programming advice, starting from Oliver Selfridge's 1958 concept of "demons" to its implementation in various Lisp systems like PILOT, Flavors, and LOOPS. This lineage eventually led to the development of the Common Lisp Object System (CLOS) and influenced modern paradigms such as Aspect-Oriented Programming (AOP) and Context-oriented Programming.
- The concept originated with Oliver Selfridge's "demons" which recognize patterns in events.
- Howard Cannon's Flavors introduced methods based on macros, acting as a precursor to around methods.
- CommonLoops was an essential component alongside Flavors that helped form the basis of CLOS.
- Aspect-oriented programming (AOP) evolved from metaobject protocols by moving toward pointcuts and compile-time approaches.
- The concept originated with Oliver Selfridge's "demons" which recognize patterns in events.
- Howard Cannon's Flavors introduced methods based on macros, acting as a precursor to around methods.
- CommonLoops was an essential component alongside Flavors that helped form the basis of CLOS.
- Aspect-oriented programming (AOP) evolved from metaobject protocols by moving toward pointcuts and compile-time approaches.
Paul Kimpel writes about a web-based emulator and operating environment designed for the IBM 1620 Model-2 computer system, which was a transistorized, decimal computing system from the 1960s. The project aims to provide a browser-based emulation of the Model 2 variant while recovering as much legacy software as possible.
- Features include support for memory sizes ranging from 20,000 to 60,000 digits.
- Includes an emulator written primarily in JavaScript and Scheme.
- The project documentation mentions various peripherals like the 1311 disk drive and 1443 line printer.
- Features include support for memory sizes ranging from 20,000 to 60,000 digits.
- Includes an emulator written primarily in JavaScript and Scheme.
- The project documentation mentions various peripherals like the 1311 disk drive and 1443 line printer.
This GitHub repository serves as a comprehensive collection of community-contributed resources for the Uxn virtual machine and its Uxntal programming language. It includes links to learning materials, documentation, emulators across various platforms (including desktop, web, and other hardware systems), creative applications, utilities, games, and specialized development tools like assemblers and disassemblers.
- Includes support for multiple languages targeting Uxn, such as C via chibicc-uxn and B via Crust.
- Features emulators for retro-style hardware including Game Boy Advance, Nintendo 64, and PlayStation Vita.
- Provides a list of community forums and IRC channels for discussion.
- Includes support for multiple languages targeting Uxn, such as C via chibicc-uxn and B via Crust.
- Features emulators for retro-style hardware including Game Boy Advance, Nintendo 64, and PlayStation Vita.
- Provides a list of community forums and IRC channels for discussion.
Fenix Guthrie writes that Chris Staecker restored a remarkably well-preserved Digi-Comp 1, the 1963 programmable educational toy computer introduced by E.S.R. The device uses mechanical logic gates programmed with soda-straw-like tubes on sliding rails and spring-loaded levers actuated by a clock switch to compute simple binary functions as a non-Turing-complete state machine reflective of early 1960s computing.
- E.S.R. originally intended to make actual computers before becoming a premier educational toy company in the 1960s
- Staecker'''s restoration used rubber bands and 3D-printed parts to return the toy to working condition
- The machine has 88 states, equivalent to 16,777,216 possible configurations
- Article references successor Digi-Comp II and other vintage ''"sort of''" computers like Geniac
- E.S.R. originally intended to make actual computers before becoming a premier educational toy company in the 1960s
- Staecker'''s restoration used rubber bands and 3D-printed parts to return the toy to working condition
- The machine has 88 states, equivalent to 16,777,216 possible configurations
- Article references successor Digi-Comp II and other vintage ''"sort of''" computers like Geniac
Zoe Skyforest writes about Kek, an emulator developed by vanheusden to bring the influential 16-bit PDP-11/70 minicomputer back to life on modern hardware. The software supports a variety of platforms including Linux, Windows, and microcontrollers like the ESP32 or Teensy 4.1.
- Emulates classic disk drives such as RK05, RL02, RP06, and RP07.
- Supports KW11-L line time clocks and DC-11 serial interfaces.
- Capable of running Unix versions from version 5 through version 7 in multi-user mode.
- Emulates classic disk drives such as RK05, RL02, RP06, and RP07.
- Supports KW11-L line time clocks and DC-11 serial interfaces.
- Capable of running Unix versions from version 5 through version 7 in multi-user mode.
Cabe Atwell writes that the Zilog Z80 is celebrating its 50th anniversary this July. Developed in 1976 by former Intel engineers, it became a dominant 8-bit processor largely due to its instruction compatibility with the existing Intel 8080 software ecosystem. This strategic design allowed manufacturers to adopt more advanced features like built-in DRAM refresh and improved interrupt systems without rewriting their entire codebases.
- Integrated into legendary hardware including Pac-Man arcade cabinets, ZX Spectrum, and TI graphing calculators.
- Launched at a competitive $25 price point to encourage mass market adoption.
- Community-driven silicon replacements are being developed following Littelfuse's cessation of Zilog orders in 2024.
- Integrated into legendary hardware including Pac-Man arcade cabinets, ZX Spectrum, and TI graphing calculators.
- Launched at a competitive $25 price point to encourage mass market adoption.
- Community-driven silicon replacements are being developed following Littelfuse's cessation of Zilog orders in 2024.
A software project that recreates the aesthetic of a 1980s cable community bulletin board for any display, with an emphasis on vintage CRT televisions. It provides a rotating broadcast including time and date, custom messages, fun facts, dad jokes, weather updates via Open-Meteo, and scrolling RSS news headlines in a retro ticker crawl.
Key features include:
A web-based control room for real-time customization of identity, timing, feeds, colors, and message rotation without needing to reload the screen.
Hardware optimization for Raspberry Pi users looking to feed video through HDMI-to-coax modulators or composite AV outputs into old TVs.
Integration with CheerLights to incorporate global color changes directly into the headline crawl.
Support for background music via local audio files and customizable overscan margins for vintage display compatibility.
Key features include:
A web-based control room for real-time customization of identity, timing, feeds, colors, and message rotation without needing to reload the screen.
Hardware optimization for Raspberry Pi users looking to feed video through HDMI-to-coax modulators or composite AV outputs into old TVs.
Integration with CheerLights to incorporate global color changes directly into the headline crawl.
Support for background music via local audio files and customizable overscan margins for vintage display compatibility.
