Overzealous n00b takes out point-of-sale terminals across the UK on a Saturday afternoon

Finds his security pass doesn't work the next day

Who, Me? Hello readers! You've found your way to the sickest of El Reg's columns, Who, Me?, where readers share their most embarrassing moments for the pleasure of everyone else.

This week, we meet "Zac", who once managed to take out major stores' point-of-sale systems across the land while working at a finance company back in the late '90s.

"I worked for a finance company that supplied POS to all the major UK retailers," he said. "Back then, it was all still AS400 IBM mainframe based with dumb terminal at the client end."

Zac was 18 and in his first help desk position, having only worked picking and packing in factories until then.

"Only several weeks into that position I was asked to cover the weekend, when 'nothing ever happens'."

Or so they said.

Then Zac received a call from one of the stores his firm worked with at around lunchtime.

"They were having a problem processing credit cards," he said.

"My brief training kicked in and I went straight to the text-based console and dutifully entered the commands to reset their connection."

Zac told the client it would be back online soon then "went to the bathroom for an extended break, chuffed at a job well done".

However, on returning about 10 to 15 minutes later, Zac found his desk surrounded by people he had never seen before.

"They said all hell had broken loose with calls to all departments as clients couldn't get through to IT."

With a sinking feeling, Zac quickly realised that he had entered the reconnect command globally, rather than just for the one client that phoned up.

"What was more it hadn't come back up for any of them."

It took a while, but Zac managed to get hold of the mainframe tech, who sorted it out – but by that point systems had been down for several hours.

And the problems didn't stop there for Zac.

"On Monday, my security pass didn't work to allow me back in the office.

"Security couldn't understand why my pass looked like it had been cancelled but with a scratch of his head allowed me through."

Zac got to his desk, and was sent straight to the big boss, who – according to Zac – "quite honestly didn't seem to give a toss".

He was made to promise that he wouldn't do it again, and "that was that". At least as far as the bosses were concerned.

"The mainframe tech, however, said what were his last words to me through gritted teeth: 'You should have been sacked.'"

"He never spoke to me again and just gave me evil eyes whenever we passed in the corridor. Quite honestly, he had scared me a little before this, but after that I actively avoided him whenever possible."

Zac said that he can still feel the panic of those few hours – which took place 21 years ago – as if they were yesterday.

When was the last time your overzealous attempt to fix a problem backfired heavily? Tell Who, Me? all about it and your story might feature on these pages in the future. ®