SMD disk specifications

Eric Smith spacewar at
Sun Dec 15 17:32:50 CST 2019

On Sun, Dec 15, 2019 at 3:05 AM jim stephens via cctalk <
cctalk at> wrote:

> I don't know that I recall SMD being a product as much as a reference to
> the interface they had though.

"SMD" was in fact a product name. The CDC976x, BK4XX, BK5XX, BK6XX, and
BK7XX series drives had the official name "CDC(R) Storage Module Drive",
from whence came the "SMD" name for the interface, starting with the 9760
in 1973.  MMD and CMD drives came along a few years later. AFAIK the MMD
drives weren't too popular in the early years, but gained traction in the
1980s. CMD drives, on the other hand, were an instant hit, starting with
the 9427 "Hawk" drive in 1977.

More information about the cctech mailing list