IBMulator is a free/libre, open source emulator for the IBM PS/1, able to run with the original ROM. The goal is to create a faithful emulation of the machine, complete of the characteristic 4-quadrant graphical user interface.
Currently IBMulator emulates the PS/1 model 2011. Model 2121 support is under development and available in the latest beta release.
The program is in active development and still in a beta status.