I knew punch cards would return!

[Don Shepherd]

(04-19-2018 02:50 PM)Paul Berger (Canada) Wrote:  A friend who worked as a programmer for a large insurance company told me they resolved the Y2K problem in a large database on an IBM mainframe by a simple change. It had been designed with a two digit year which was stored in packed decimal which would require two bytes because of the sign nibble and one digit nibble would always be zero so for anything after 2000 they simply changed that nibble to a non-zero value which only require minimal changes to the program and none to the database itself.

While preparing for a talk on IBM punchcard systems for HHC2017 I discovered that the US Army, during WW2, used IBM tabulation and unit record systems for all kinds of things, and they frequently stored the month code in one column in the IBM card. And sometimes they stored the year code in one column as well (perhaps hoping or assuming that the war would be over before 1950 I suppose). 80-column IBM cards were great for their time, but when you only have 80 columns you have to compromise. And when magnetic disks came along, you still compromised because disk storage wasn't cheap.

I hope I am alive in 9999 to warn of the dangers inherent in the 4-digit year!