The above simulation is configured for a clock speed of 4.77Mhz, with 256Kb of RAM and a CGA display, using the original IBM PC Model 5160 ROM BIOS and CGA font ROM.
This PC XT configuration also includes a 10Mb hard disk with Windows 1.01 pre-installed. This particular configuration will NOT save any changes when your browser exits, since it has been pre-configured to always start Windows 1.01 in the same state.
NOTE: The Windows 1.01 mouse pointer can be controlled with your mouse, but only when your mouse is within the "CGA Display" window. This is a restriction imposed by your web browser, not PCjs.
For more control over this machine, here's an alternate configuration with the Debugger and save/restore enabled.