PDP-8 RK05's are 16 sectors, PDP-11 RK05's are
12 sectors.
I don't know about the RK01, but the RK02 through RK05 (excluding
RK05F) all present the same geometry.
Actaully, the geometry of the RK05f is the same as the RK05, it just
appears as 2 drives. Each 'drive' has the same number of cylinders,
heads, and sectors as a normal RK05.
Was there ever a 16 sector version of the RK05f for the PDP8? I've only
ever seen 12 sector ones.
In non-DEC uses, I believe there were 8-sectored packs in common use.
Somewhere I have at least one manual on the RK01. I seem to remember that
was an 8 sector device, but I certainly wouldn't put any money on that :-)
-tony