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IBM History

Forgotten Voice

Cliff Paffett
Customer Engineering
Croydon, Greenock, Hursley and North Harbour
Date Joined:
September 1974
Date Left:
September 2014
Tricky System/370 Operators

When I joined IBM Croydon Branch 02 in 1974 and before I did the Customer Engineer course (in those days was three months in Sudbury), I had to do loads of Preventative Maintenance (PM). This involved cleaning the filters in the mainframe and I/O devices, topping up the oil in printers and disk drives (they worked on hydraulics), and checking error logs. One of our customers was Philips and it was the first time I had arrived to do PM. I rang the bell to gain access to the machine room, the door had a glass panel in it so the operator could see who wanted to get in.

Philips had a 370 155, the front panel of which was at right angles to the door. The 155 front panel was about 3x4 feet completely filled with switches and bulbs showing the contents of various registers, CPU and storage. As I approached the operator, he said, "Glad you arrived we have a problem, the mainframe has just gone down." He was right, all the bulbs were off. We never admitted we didn't know what we were doing, so I opened the covers connected an oscilloscope to a random part of electronics and opened the manuals.

The 370 range of mainframes when powered up first ran internal diagnostics, I was just about to power the mainframe off and back on, when the operator stopped me. As I was new, when he let me in the machine room he flicked a switch which turned all the bulbs OFF (the other way put them all on so you could detect duff bulbs). In normal operation the bulbs would flash on and off. Had I been a bit quicker then the operator would have been in a bit of trouble and the laugh would have been on him rather than me.

All part of being the new guy.