System 370

IBM System 370 circuitry in 1975 used some System 360 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:

Mus.Cat. NEWUC:2005.75 Mnfctr: IBM Date: August 1972 Form No: G520-2633-0 Model: -
Comp: System 370 Facts Folder Height: 216 mm Width: 90 mm Depth: 3 mm Weight: 46 g

Provides a wealth of information.

Front view

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 ...

Rear view

and opening one of the panels we can see the cards plugged into a back panel. We can also see the (yellow) wiring to the control panel.

Card removed

This is one of the plug in circuit cards.

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

Card removed

This is a card removed and a close-up of ...

Top removed

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 transistor chip.
Mus.Cat. NEWUC:2003.22 Mnfctr: IBM Date: August 1974 Part No: 2572830 Model: -
Comp: Water Cooled Board Height: 239 mm Width: 191 mm Depth: 55 mm Weight: 1526 g

Water cooled

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.

Water cooled

The chilled water entered at one of the copper pipes at the bottom, and exited the other.

I am guessing it is a switched mode power supply but do not know. Anyone know?

Bill Taebel feedback