When Warships Pass

I've always enjoyed messing with computers and finding solutions my own way. Never had any formal training. And some of my solutions have been a bit... Out there.

I once designed and built an automation system for a foreign exchange business that retrieved exchange rate data, applied some formulas for building in margins, then sent the data out to 7-8 branch locations.

‌‌It worked great, mostly, but would occasionally bug out and crash. ‌‌It took a while to diagnose: although it was automated, I was always there to monitor it because it was vital. And sometimes, just sometimes, the data was garbage.‌‌ It turned out that the factor that made it crash was warships.

‌‌----The owners of the business didn't want to pay for something professional like a Reuters terminal or other data connection (or a real programmer). This was the mid-nineties and such things were expensive. There weren't any reliable free services for such data... But there _was_ Teletext.‌‌

So, I popped a TV capture card into a PC, and found a freeware program that would scrape a Teletext page and save the content as a text doc. Then there was a predictable Excel workbook with macro that would load the data from text, apply the formulas and save a fresh CSV into an Export folder.‌‌ Inter-office connectivity was ISDN, 64kps. There was a batch file that picked up the ISDN line to branch one, squirted out the file (and some comms stuff, head office messages etc). ‌‌It then dropped the line, picked up again to connect to branch two... Etc. There was no internet involvement at all, just direct point to point. Once transmitted, a batch file on the remote end threw a message up on the manager's machine, so that they could 'accept' the new exchange rate data. If they did, it updated the electronic rates board displays by serial connection, and updated the transaction terminals. I was ridiculously proud of it, it saved an enormous amount of work.

‌‌But it would very occasionally throw a fit and Bork out. It took me a long time to realise the cause. The head office location was by the harbour entrance where warships regularly came in and out. If we were grabbing the Teletext data at the exact moment a warship passed, some kind of electronic fizz from the warship would momentarily glitch the page and futz that data.

‌From then on, my documentation for the system had the instruction: look for warships and wait for them to pass before hitting 'go'.