True Story No17


Core blimey, what's going on!

When a computer went wrong some people blamed hardware and some software.

In fact the reason used to be about 50-50.

Programmers usually blamed the hardware and engineers usually blamed the software.

Hardware reliability and Windows 98 changed all that and now most, quite rightly, blame Windows 98.

Many years ago I was helping to commission a new computer.

The machine was to form part of a demonstration to the Australian Post Office.

Three of the computers were to be connected in a ring and handle simulated phone traffic without falling over.

The system was supposed to keep on working if any single computer or even two computers failed.

The timescale for the demonstration meant we had to work 24 hours a day (in two shifts) to finish the hardware and software development.

I was one of two engineers on the engineering shift and we worked our 12 hours testing hardware.

If anything needed sorting out on the software front we had a programmer to help us. I recall that he used a software language called "Minicoral". It seems funny now, but it didn't seem odd at the time; if he needed to do any major recompiling he used to go 200 odd miles to West Drayton and do it using the UK "4-minute warning", Air Defence System!

I suppose, because we'd supplied it, we thought we were co-owners!

The other shift had two programmers debugging software with an engineer to help them if required.

At the beginning of a 12 hour shift you had to take over from the other team and at the end, hand back over again.

At the end of a period of such intense thinking and problem solving, one's brain got a bit worn out. The effect was peculiar. Near the end of a shift, say at five or six in the morning, one could see things really clearly and solutions to problems used to be really obvious. Unfortunately, in reality they weren't and it was just because ones brain was worn out.

We had a log book and at the start of a session, when you read what you'd written at the end of the last shift, you couldn't imagine how daft you'd been.

One morning when myself and my fellow engineer arrived we found the two programmers rummaging around inside the computers memory, watched with interest, by their engineer.

The computer had a "core store" which used miniature ferrite rings on which to store a bit of data.

The store was 24 bits wide and 4k deep.

In modern parlance that's 12kbytes.

The core store occupied a 19" rack mounted unit about 12" high which weighed about 60 pounds and most likely would have been worth a years salary. There were a total of 96,000 ferrite rings in the unit and these were held in an incredibly densely packed module which looked a bit like a 3-dimensional spiders web in the shape of a 4" cube.

One of the programmers had the ferrite ring module on the bench and he had a soldering iron in his hand.

We were flabbergasted.

"What on earth are you doing", I asked.

"Oh", he said, not looking up, "We reckon two of the bits are the wrong way round and I'm just rewiring them".

Of course he'd had a program fault and he'd blamed the hardware.

We had to get a new core store before we could start our shift as he'd wrecked ours.

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