 Various configuration options could be set before launch, and returning to normal IBM compatible mode was a simple matter of running the same program again with a particular option switch.It is not clear whether this was purely a software trick using emulation or DOS drivers that provided a compatibility layer between DOS and the old PC186 programs, or something included in the machines' hardware at the BIOS level, but it did take over the computer completely enough that many MS-DOS programs, including Windows, cannot be run whilst in PC186 mode.RM Nimbus PCs were usually connected to local area network supplied by RM.