DUCM et alii Release 1 23rd September 1986 This set of programmes allows users to access large MSCP discs under TSX-plus. It has the following features: (1) The handlers are internally queueing, allowing up to 32 requests to be queued to an MSCP controller at a time. This speeds up multi-job RT-11 and TSX usage considerably. (2) The handlers may be mapped under TSX-plus, saving low memory for additional jobs. (3) [TSX] Any number of discs of any size may be accessed at the same time, without any need for SET commands which could compromise TSX-plus security. This requires a Q-bus system (4) A DY: handler is included for DILOG and SIGMA controllers. It is a mapped RX03 handler, but the only documentation for it is in the source file. Anyone who would like to extend it for other handlers is welcome: the author would appreciate a copy! (5) A programme (TSMUNG) is included to get TSX to allow DU (and optionally DY) handlers to be mapped.