The 6502-family CPUs in Commodore 8-bit computers famously used 64K of RAM at a time. But in 1985, Commodore introduced a cartridge that added up to 512K of RAM to the 128. Commodore followed up soon after with a 256K cartridge for the 64. How did Commodore RAM expansion units work?

David Farquhar is a computer security professional, entrepreneur, and author. He has written professionally about computers since 1991, so he was writing about retro computers when they were still new. He has been working in IT professionally since 1994 and has specialized in vulnerability management since 2013. He holds Security+ and CISSP certifications. Today he blogs five times a week, mostly about retro computers and retro gaming covering the time period from 1975 to 2000.

