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Brent Rector — retrocomputing obsessive, FPGA tinkerer, AI explorer.
Five decades in software and still finding new rabbit holes.
Research scientist. The subject is computers. The method is obsession.
Based in San Diego.

Deep dives into
machines that matter.

Technical explorations of retrocomputing, FPGA hardware, emulator design, and language implementation — written for people who want to understand how things actually work.

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Apple II6502FPGAEmulationSmalltalkVerilogCopy ProtectionRetrocomputing

Featured Projects

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Apple ][ + Microsoft Z-80 SoftCard + Videx Videoterm

Microsoft SoftCard CP/M on a Videx

Reverse-engineering why Microsoft SoftCard CP/M 2.20 won't boot on a Videx Videoterm 80-column card and 2.23 does. 11 bytes of 6502 code that read the Pascal 1.1 signature byte the Videx ROM has exposed since 1980 — a 1982 fix that's Videx-shaped but not Videx-specific.

apple-ii6502z80

.NET 9 / Windows

Smalltalk from Scratch

A complete Smalltalk-80 interpreter and modern runtime in C# — Blue Book bytecodes, a coldstart image loader, SDL2/SkiaSharp display, and a 884-test CI suite running headless on GitHub Actions.

smalltalkcompilervirtual-machine

Apple ][ + Microsoft Z-80 SoftCard

Building Microsoft SoftCard CP/M from Source

Annotated 6502 and Z-80 assembly sources for Microsoft SoftCard CP/M 2.20 and 2.23, with a build tool that packs them into a byte-identical .DSK. The deliverable that fell out of the cpm-videx investigation — a reproducible disk image, region by region.

apple-ii6502z80

Tang Nano 20K / GW2AR-18C

A2FPGA: Five Cards, One Board

A fork of the A2FPGA Multicard Core that adds Videx VideoTerm 80-column card emulation and ThunderClock Plus clock card emulation to a Tang Nano 20K FPGA board — alongside three upstream bus timing bug fixes that had gone unnoticed for two years.

apple-iifpgaemulation