The 5363 was a "hybrid" machine -- IBM was starting to use some technology (like the ISA bus, memory cards, etc.) in these machines, to make them smaller and more cost-efficient. The 5363 was the last model of System/36 prouced -- it actually came out after the 5364 "Baby/36" model. The System/36 family was developed and produced by "GSD" (General Systems Division) -- the same folks who produced the IBM PC. All of the System/36 machine did use an IOP (what were called "channels" on System/34) -- to off-load the work of managing I/O from the main CPU ... that would explain the 286 processor to "manage" the I/O queue ... and the memory for I/O buffers, etc. This card was not running anything like PC-DOS -- it would have an embedded control program in ROM on-board for the IOP software. Hope that helps.