The original sources of MS-DOS 1.25, 2.0, and 4.0 for reference purposes

Official repository for 8086tiny: a tiny PC emulator/virtual machine

The development kit for over a hundred z80 family machines - c compiler, assembler, linker, libraries.

BIOS for Intel 8088 based computers

Microsoft BASIC for 6502 (Commodore, Apple, KIM-1, AIM-65, OSI, ...)

An open source sort-of CP/M 2.2 distribution.

Historical source code for Infocom's Z-machine interpreters

System Software for Z80/Z180/Z280 Computers

Official RC2014 repository for hardware schematics / software and more!

8-bit ATmega1284 retro computer

Minimal 68000-based single board computer

CP/M for the 6502

8088 PC XT Compatible

Atari ST ACSI to SD card converter with a STM32

Firmware to allow functional testing of ZX Spectrum hardware and related clones. See the wiki for full details.

ISA 8-Bit Ethernet Controller

An MPU-401 emulation TSR for DOS

Set of programs to test the implementation of the Zilog Z80 instruction set.

Diagnostics program for the Amstrad CPC.

Neo6502 Modern Retro Computer with W65C02S processor and RP2040 memory and peripherals emulator

"Anyone who has brought up CP/M on a homebuilt computer has felt this moment of elation. A myriad of connections are properly closed; bits are flying at lightning speeds over busses and through cir…

Re-make of the Soviet Ham Radio computer published in Radio Magazine in 1986

6502 learning platform in a familiar form factor

Official AGON QUARK Firmware: BASIC Interpreter

Retro Z80 CPU Board

LUnix Next Generation - a Little Unix operating system for C64/128/Atari and any 6502-based machine

6502 enhanced BASIC unmodified source

8 bits de poder ( 8 bits of power)

Z80 8085 MS BASIC Version 4.7 - (C) 1978 Microsoft

Modern version of CP/M written as a compatible OS to CP/M 2.2 written from scratch in z80 Assembly - Created in the same way DOS was.