The most apparent change when migrating from MPE V to MPE/iX
is the hardware configuration. The ATP/ADCC interface cards are
placed directly in the SPU of MPE V computers. Therefore, the RS-232/422
cabling for asynchronous devices connects directly into the system
cabinet. In comparison, MPE/iX computers use DTCs (Datacommunications
and Terminal Controllers) connected as nodes on a LAN. The interface
cards to which the cables of devices are connected reside in the
DTC. To communicate with asynchronous devices, the SPU must hold
only the interface card for the LAN.
Although the physical environment of the subsystem on MPE/iX
computers looks very different from that of MPE V computers, the
resultant functions and characteristics of the subsystem software
are very similar. In fact, as long as an asynchronous device is
supported on both systems, very little difference should exist between
using the device on an MPE V computer and using it on an MPE/iX
computer.
