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The 701 was formally announced on May 21, 1952. It was the unit of the overall 701
Data Processing System in which actual calculations were performed. That activity
involved
274 assemblies
executing all the system's
computing and control functions by means of electronic pulses emitted at speeds
ranging up to one million a second.
The 701 contained the arithmetic components, the input and output control circuitry,
and the stored program control circuitry. Also mounted on the 701 was the operator's
panel. The arithmetic section contained the memory register, accumulator register
and the multiplier-quotient register. Each register had a capacity of 35 bits and
sign. The accumulator register also had two extra positions called register overflow
positions.
The control section decoded the stored programs and directed the machine in automatically
performing its instructions. Instructions could only be entered into the control
section through electrostatic storage or manually from the operator's panel. The
entire machine could be manually controlled from the
operator's panel through
various buttons, keys, switches and signal lights. The operator could manually
control the insertion of information into electrostatic storage or the various
registers. The contents of the various registers could also be displayed in
neon lights for the operator to observe.
The operator's panel was used primarily when beginning an operation on the 701 and
when initially testing a program for a new operation.
Also included with the Analytical Control Unit were the
IBM 736 Power Frame #1,
741 Power Frame #2
and the
746 Power Distribution Unit.
Those three power units supplied the power for all units in the 701 system.
The functional machine cycle of the 701 was 12 microseconds; the time required
to execute an instruction or a sequence of instructions was an integral multiple
of this cycle or 456 microseconds were required for the execution of a multiply or
divide instruction. The 701 could execute 33 different operations.
In the above view of the 701, the computing and control section is open, revealing
part of its intricate wiring. At the immediate right of the operator's position is
the
IBM 711 Punched Card Reader
where the operator inserted punched cards carrying additional data or instructions.
The monthly rental for a 701 unit was approximately $8,100. The 701 was withdrawn
from marketing on October 1, 1954.
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