Plessey 6742/0

S/N 322

 This Plessey system contains a DEC M8186 11/23 CPU board but all of the remaining boards are manufactured by Plessey Microsystems of Irvine California. The disk is an 8" Memorex with a capacity of about 80 MB. The Plessey disk controller makes the single Memorex disk look like three RK07 disks. It also contains a QIC 1/4" tape drive. The backplane is Q-bus but is hex-wide instead of the normal quad-wide. The backplane has a proprietary memory bus and the system has a mapper board. The mapper board makes this system a 6700 series instead of a 6600 series. RSTS-E 7.2-04 with an install date of 1984 is on the disk.