SMD (was Re: All things ESDI)

On 5/5/05, Liam Proven <lproven at gmail.com> wrote: SMD was another drive interface of 20-something years ago.... rather than a 34-pin digital controller cable and a 20-pin analog one-per-drive cable, it used a 60-pin digital cable and a 26-pin one-per-drive analog cable. Among the more famous SMD devices in DEC world were the CDC 9762, 9766, and Fujitsu Eagle and Super Eagle. SMD drives were routinely in the 14" to 8" range, going from dozens to hundreds of megabytes, with some later ones in the 5.25" size. I do not know if all of the 5.25" devices were SMD-E or not (newer version of the interface for faster drives). Perhaps someone could chime in about that. ISTR there were Qbus controllers for SMD-E as well as SMD. DEC didn't officially support SMD (there were some SMD-like interfaces embedded in some of DECs drive lines like the RB80 or the RM03, but they weren't entirely compatible with true SMD, and they weren't meant to be fiddled with by the end users), but there _were_ 3rd party true SMD disk controllers by Emulex, Dilog, and others. I have a few Systems Industries SI9900s that were SMD to the drives, and proprietary SI interface to an SI host card for Qbus or Massbus (perhaps Unibus, too; but I've never seen that interface). While they aren't the only drives in town, I have yet to see an S9900 that does not have a Fuji Eagle attached. They used to be a good value and quite robust (and around 400MB!) SMD drives were uncommon for PC-class hardware, but were quite common for minicomputers, especially in the PDP-11 and VAX worlds where people didn't want to pay DEC's prices for DEC's disks. -ethan