Panic in the mailroom: The perils of an operating system too smart for its own good

Who, Me? Modern life is rubbish, so take a trip back to the 1970s with a Who, Me? all about the Master Control Program (MCP).

Today's tale comes from a Reg reader we'll call "Simon." Our man was spending 1973 toiling away as a computer operator for an American city. The city was big enough to justify splashing some dollars on a new Burroughs B-6700 mainframe "and we were still learning the magnificent multi-cpu, multi-tasking operating system known as MCP."

It was heady stuff. The Burroughs B-6700 was an unusual beast; eschewing machine code in favour of higher level languages. ALGOL was a particular favourite, although application languages such as COBOL were on offer.

The operating system, the Master Control Program - not to be confused with the fictitious computer program villain from Tron - was also an innovation. Multiple programs could share the system and more than one processor could run programs. Now approaching 60 years since its initial release, vestiges of the OS can still be found lurking on the Unisys website in ClearPath MCP Release 19 guise.

Back in 1973, Simon was using the mainframe to run billing jobs for the city-owned electricity utility. "This generated 20,000 - 30,000 bills each night," he explained, "the billing program sent the output to a printer backup tape which was then printed using a system utility."

At this point, it is worth noting that a "feature" of this particular edition of the MCP was the automatic restart of certain system utilities after system fault and reboot.

"One of the restartables was the program that printed from printer backup tape..." said Simon, for whom the significance of this fact would become horribly clear.

On the night in question, Simon had been assigned the task of dealing with the billing for the electricity utility. The billing program had done its stuff, as it always did, and Simon was diligently returning the tapes to storage when the MCP abruptly fell over and the Burroughs restarted.

Only four people were on shift, and it was all hands to the pumps to get everything running again. Simon noted that the printer had restarted and gave silent thanks for whatever colleague had saved him the task of dealing with it. Once complete, he trotted down to the mailroom with the stack of printed bills.

Neither Simon, nor those in the mailroom that did the mailing, spotted that around 2,500 bills had been printed twice.

The customers, however, did.

"A few days later some people called the newspaper to report receiving two bills for that month," he said. "You really don't want to end up on the front page of the newspaper."

"Meetings were held. Much shouting and wailing and gnashing of teeth," he recalled. "Fortunately, the big boss wanted to squeeze concessions out of Burroughs that week so the blame fell on them for lack of documentation and training."

For Simon, things took a more surreal turn. Having had to endure a dinner of fingerpointing from his parents (who were also on the receiving end of twin bills) he discovered that a few of his fellow citizens took a city hall cock-up a little too seriously:

"Some wackadoodles were less forgiving. We received a bomb threat in the data centre a few weeks later."

Ever screwed something up so comprehensively that you've found yourself on the end of potential physical as well as verbal abuse? Or forgotten the perils of an unplanned restart? We've been there. Send an email to Who, Me? if you have too. ®