It was popular with govt because it came with an HDLC network build-in, server/client depended on the OS you booted. This saved you a network administrator.

The kernel was in Intel ASM86 but the rest of the OS was written in PLM86. When I joined it was 2MB of code on a 128K 8086 cpu. By the time I left it was 9MB of code running on an 80386.