System/360 Model 40

IBM System/360 Model 40

IBM System/360 Model 40
Announced April 7, 1964 and
withdrawn October 7, 1977.

The IBM System/360 Model 40 had approximately three times the internal power of the Model 30 when performing a mix of computations. It was a powerful stand-alone system in the medium price range with communication facilities.

Typical arithmetic operations per second

Decimal add (5 + 5 digits) 24,600
Fixed point add (1 word + 1 word) (32 bits) 133,300
Fixed point multiply (1 word x 1 word) 12,000
Fixed point divide (2 words div. by 1 word) 5,400
Floating point multiply (1 word x 1 word) 13,100

Feeds & speeds

Speed Data width (bits)
Machine cycle time 625 nanosec.  
Logic circuits 30 nanosec. 8
Memory cycle time
    16K, 32K, 64K, 128K, 256K
2.5 microsec. 16
Registers
    16 general purpose
    4 floating point

1.25 microsec.
2.5 microsec.

32
64
Control
    Read only storage
    Special 1401 compatible feature

625 microsec.
 
Data rate
per channel
(Char. a Sec.)
Control units
per channel
I/O units
per channel
Channels:
    Selector
    (up to 2)

400,000

8

256 each
    Multiplexor
      Multiplex mode
      Burst mode

31,000
200,000

8

128