The 3138 was a follow on from the 3135. Maximum storage of 1 Megabyte and
reloadable control storage of 132K. The CPU cycle time was 275-1485 nanoseconds.
I/O again was connected similarly to the 3135 via integrated adapters or
channels. 2 Byte Multiplexer channels were now standard as well as many of what had been
features on the 3135.
Extended Control Program Support was standard on the 3138 this was a Hardware
Assist that reduced the CPU time needed to execute certain frequently used supervisor
functions in VM/370 and OS VS1 operating systems.
From an external view the major difference was the consul printer keyboard had
been replaced by a 3270 type VDU and Keyboard.
Again the 400Htz power was supplied by a 3046 Motor Generator.
Below you see the 3138 CPU and the 3278 Monitor in place of the 3210 printer
Keyboard.