The IBM PS/1, sometimes called the IBM PS1, was a line of 1990s personal computer systems, not to be confused with the Sony Playstation video game console that’s also often called the PS1. The PS/1 was IBM’s second attempt at a mass market consumer PC, after the ill-fated PCjr.
You can neatly divide the PS/1 into two generations. While they ran the same software, they had major philosophical differences. Perhaps more than any other computer line, they represent IBM’s change of heart in the early 1990s as it tried to survive in an extremely competitive and crowded market.