The Commodore PET was one of the first true PCs. The entry model PET 2001 in 1977 came with 8K of RAM. My own PET 3016 from 1979 came with 16K, which I upgraded a while ago to 32K of RAM. This lets us run a lot of software, even interactive fiction games, for example Planetfall and Zork by Infocom. However we can do better! Using the SoftROM expansion we can add an additional 8K of SRAM to our system, that can be used by the Infocom interpreter, or any other software that knows about it and is changed accordingly.