A company I used to work for produced a VME expansion chassis, serial ports, parallel ports, T1, MIL-STD-1553, a real-time clock, and did some initial work on IEEE-488. I was the only device driver guy, and I supported most of these (exceptions being VME (supported by DEC) and IEEE-488 (DEC did a device driver, but I was too busy to document and package it; had I not been too busy, _I_ would have written the driver to begin with) under Ultrix, OSF/1, Alpha/VMS, and VAX/VMS. I did a device driver for one of the modules under MIPS/OSF/1, but that never went anywhere because DEC pulled the plug on that OS (I do have tapes somewhere, though). I did some work with another company's TC QBus expansion chassis and I designed the TC adapter for the VAXstation 4000/60 and /90. I'm aware of other TC VMEbus expansion chassis (DEC had one, as did Bit3), other serial and parallel ports (Magma), and several other options. TURBOchannel was very easy to interface to; the bus interface on most of our options consisted of a rank of registered bus transceivers and a PAL22V10. I once built a bus torture device from a rank of registered bus transceivers and an AM29CPL154; with only those five parts, I could exercise the entire bus protocol, including determining the maximum DMA burst length. PCI, on the other hand, requires some pretty complex state machines. Roger Ivie ivie(a)cc.usu.edu