Andrew, somehow I feel you won't be offended by some gentle train-spotting. I came across your site by a circuitous route that doesn't really matter, and followed a thread from the Big Blue Room to the Big Red Switch.
I didn't start my DP (remember that's what we called it then?) career quite as early as you - I first cut my teeth on an IBM 370/125 - but I do recall that the big red switch was called an EPO. It means of course "Emergency Power Off" and while the earlier models may have had an Emergency Pull button it wasn't long before IBM invented a TLA for everything.
I only once saw the EPO button pulled - when the water cooling system on a 4300 series mainframe conked out and it was getting pretty hot. The IBM Systems Engineer (Glen McDonald if memory serves) came down from Queen Street in about 4 minutes flat, and spent the next 3 hours happily reconnecting all the EPO cables under the floor to the power switch of each device. Those were the days.
Big Red Switch
Andrew, somehow I feel you won't be offended by some gentle train-spotting. I came across your site by a circuitous route that doesn't really matter, and followed a thread from the Big Blue Room to the Big Red Switch.
I didn't start my DP (remember that's what we called it then?) career quite as early as you - I first cut my teeth on an IBM 370/125 - but I do recall that the big red switch was called an EPO. It means of course "Emergency Power Off" and while the earlier models may have had an Emergency Pull button it wasn't long before IBM invented a TLA for everything.
I only once saw the EPO button pulled - when the water cooling system on a 4300 series mainframe conked out and it was getting pretty hot. The IBM Systems Engineer (Glen McDonald if memory serves) came down from Queen Street in about 4 minutes flat, and spent the next 3 hours happily reconnecting all the EPO cables under the floor to the power switch of each device. Those were the days.