Many, if not most, large companies are filled up with tons of old software that no one remembers even exists, silently running processes in the background that are like gravity in that you assume it is always there due to be ubiquitous in our daily lives. About a decade ago I discovered a critical process running on machines in every Home Depot store relied on a program called Batchman, which was a type-in utility from a 1989 issue of PC Magazine. Breaking compatibility would require someone to go in and recreate the process that's been silently running for decades. No one I talked to on the HD team I was working with had ever seen that code before and had no idea what Batchman was or what it was doing.
