[jimohalloranau]

My first IT job was supporting Point of Sale systems for service stations and other retail outlets. The company had some clients in really remote areas, and we provided 24 hour phone support. The software we supported was DOS based, and the configuration was really arcane. Lots of serial port hardware, but instead of configuring it on a COMn port, you needed to know the exact port address and interrupt. This incident happened back in the mid-90's, so very much pre-internet.

One Saturday afternoon a call was escalated to my mobile while I was at a friend's house. A remote site had a server failure, everything was down, and they couldn't pump petrol, help! I spent a little bit of investigation aided only by a non-technical console operator acting as my remote hands we determined the server was beyond repair. So then I talked the operator through installing the network operating system on a different computer, reinstalling the POS software, re-configuring all of the serial hardware for the ports on the new machine, setting up file sharing, restoring data backups, etc. Essentially building an entirely new system from scratch.

After 4-5 hours on the phone they were back up and pumping petrol again. All completely from memory, no computer, manuals or documentation to hand.