Today’s exciting news on Twitter is that one or more of the Department of Defense systems used to coordinate ICBMs and nuclear bombers still use 8-inch floppy disks. A spokesperson for the DoD explained, “It still works.” The computer is an IBM Series/1 that dates from the seventies.
This isn’t as surprising as it might seem. The Space Shuttle never upgraded its computers over two decades, because of the fear of introducing literally fatal bugs. (Correction: There was one upgrade.) When a software error could start World War III, you need to be cautious. On the other hand, floppies are extremely fragile, and it’s hard to think of any system that uses them as reliable.
It’s not clear how many computers fall under this case. The BBC article has a grammatical disagreement between “systems” and the singular verb “runs.” Perhaps it’s just one system with redundant copies. Redundant systems that “vote” in case of disagreement are common for life-critical installations.
Maintaining it has to be absurdly expensive. Evidently IBM still supports the Series/1, perhaps just for this one customer. This means having replacements for its components, and being ready to deliver them fast when they’re needed.
The article claims that “floppy disks are not actually floppy.” This is a bit of hairsplitting. The envelope which holds an 8-inch disk is stiff enough that it won’t noticeably bend when you hold it, but it is flexible, and the disk itself would just flop over without its enclosure. Those disks are exposed to the air, and small magnetic fields can ruin them. The security measures to make sure no dust or magnets get near them must be fascinating.
Hopefully the DoD will replace this system — and give its replacement some really thorough testing.