Building the Tynemouth Mini PET
Ultimate Commodore Charset / PETSCII / Keyboard Reference
Another addition to the The Ultimate C64 Reference: We’re adding character sets, PETSCII codes and keyboard layouts – supporting eight different Commodore computers.
The Commodore IEEE-488 Cartridge for C64
Commodore 64 disk drives were usually connected through the slow serial bus. This article shows some hi-res photos of the Commodore “IEEE-488 cartridge”, which made the faster PET drives available for the C64.
Commodore Peripheral Bus: Part 1: IEEE-488
In the series about the variants of the Commodore Peripheral Bus family, this article covers the lowest two layers (electrical and byte transfer) of the IEEE-488 bus as found on the PET/CBM series.
Building the Original Commodore 64 KERNAL Source
Many reverse-engineered versions of “KERNAL”, the C64’s ROM operating system exist, and some of them even in a form that can be built into the original binary. But how about building the original C64 KERNAL source with the original tools?
Microsoft BASIC for 6502 Original Source Code 
This is the original 1978 source code of Microsoft BASIC for 6502 with all original comments, documentation and easter eggs: