DUCM/DYC Release 2b 10th December 1986 This set of programmes allows users to access large MSCP discs under TSX-plus. It has the following features: (1) [DUCM] 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) [DUCM/DYC] The handlers may be mapped under TSX-plus, saving low memory for additional jobs. (3) [DUCM+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) [DYC] is a mapped DY: RX03 (double sided RX02) handler for DILOG and SIGMA controllers. Anyone who would like to extend it for other controllers is welcome: the author would appreciate a copy (on RX03 of course...). If the handler is run as a programme it allows formatting of RX01/02/03 floppies, without requiring any privileges under TSX-plus. (5) A programme (TSMUNG) is included to get TSX to allow DU and/or DY handlers to be mapped. This version contains bug fixes and enhancements over previous versions, including the version on the 1986 Australian SIG tape.