System 370

IBM System 370 circuitry in 1975 used some SLT technology
but introduced monolithic processor storage and did not use core storage.
The monolithic storage was smaller, faster, and used less power.
The System 370 technology also introduced a high speed buffer store
between the CPU and the RAM, a cache, and overlapped instruction execution.
This latter feature allowed up to three instructions to be in process of execution

A System 370 Model 168 Facts Folder is in the museum:

Provides a wealth of information.

This is a photograph of a gate in a
3803 Magnetic Tape Control Unit.
To it was connected one to four tape drives
which shared this control circuitry.
Only one of the tape drives could be
in operation at any one time.

Our interest here, however, is the
packaging of the circuitry.
It was the same for the System 360 and 370 computers.

The gates held a number of back panels
that had additional (yellow) back wiring
connected by (white) ribbon cables

Often the gates had a control panel,
as here, to see what was going on
and in diagnostic mode to find out
what was wrong when there was a problem.

Looking at the rear of the gate ...

and opening one of the panels
we can see the cards plugged into a back panel.

this is one of the plug in circuit cards.

This is a photograph of a back panel
and its cards, out of a gate.

This is a card removed and a close-up of ...
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of one of its capsules with its cap removed.

Here you can see 16 conductors to a chip,
more than the just three to a 360 chip.

Interestingly the System 370 computer was water cooled.
Most computer manufactures would not mix water with electronics.

This is one of the water cooled boards from the 370 computer,
this a power supply component.

There is a mixture of technology here
four transistors, the round metal components
four SLT components, the 1/2inch square metal caps,
and an assortment of other components.

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Bill Taebel feedback

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