 The directory consists of an array of entries, one per file or unallocated space.Each directory entry is 8 (or more) 16-bit words, though a sysgen option allowed extra application-specific storage.Many RT11 programs (those that did not need specialized peripherals or direct access to the hardware) could be directly executed using the RT11 RTS (Run-time system) of the RSTS/E timesharing system or under RTEM (RT Emulator) on various releases of both RSX-11 and VMS.