On 18 Apr 2005 at 11:54, David Comley wrote: 09134-90032, August 1983): "The 4-Volume configurations cause a 5 Mbyte drive to appear, to the host, as a four-unit 9895A flexible disc. [...] The controller also identifies itself to the host as a 9895A. "The Single-Volume configuration is similar to the 4-Volume in that they also use the 9895A Amigo protocol. With the Single-Volume, however, a drive does not appear to the host to be indentical [sic] to the 9895A." The four-volume configuration supplies "Identify" bytes 00H/81H (same as the 9895A?). The single-volume configuration supplies "Identify" bytes 01H/06H. According to the service manual, there were three controller boards used in the 9134A: * 09135-69515 for the standard configuration * 09135-69501 for option 010 * 09133-69514 for both standard and option 010 after S/N 2151A04165 Only the last had jumpers for one volume/four volume configuration. So if you had one of the earlier units, you'd apparently need a controller swap to effect the change. For the later unit, there's a "one volume" jumper that is installed for option 010, removed for standard. If your unit is not marked Option 010, then the best bet would be to open it up and see which controller is inside to confirm. -- Dave