14" drives with the type of head in the photo (or similar) would have been from 2.5mb / side to 5mb / side of platter. CDC came out with the Hawk, I think (all their drives were birds then) and which was an 8" drive, and it had 20mb, 20mb on each side of a platter. I don't recall the name, but they also had a removable cartidge type drive with a single platter as well. An 8" drive which was not ANSI interfaced or SMD interface would have been unusual. I don't know if PDP8's ever had an interface to SMD other than maybe odd knockoff vendors. The 14" drive they used would have had RF from the heads on the interface cable, and a servo signal doing the seek, rather than the SMD drives later use of an address on the cable, and ANSI's attempt to get rid of both RF for the data, and going to a sort of protocol similar to scsi. Infomag sold positioners to Microdata, who had drives of both the type mentioned above, as well as a winchester design. There was also other Southern California drive makers who used them as well. I belive that Priam used them in their drives, as well as some up in the valley, such as Micropolis. It is interesting that the media coating on the platter seems to be silver in color, so the media may have been metal plated, rather than oxide coated. I could not tell much from the photo quality about that. some magna-see on the surface would be interesting, as you could then measure the track spacing Jim "A. G. Carrick" wrote: