“LAYERS AND LEGACIES: A lot of software is now old enough to be multi-layered. Airline reservation systems are particularly glitchy since they’ve been around a while. I wouldn’t be surprised if there is some mainframe code from the 1960s still running part of that beast. In the nineties, I paid for parts of my college education by making such old software work on newer machines. Sometimes, I was handed a database, and some executable (compiled) code that nobody had the source code for. The mystery code did some things to the database. Now more things needed to be done. The sane solution would have been to port the whole system to newer machines, fully, with new source code. But the company neither had the money nor the time to fix it like that, once and for all. So I wrote more code that intervened between the old programs and the old database, and added some options that the management wanted. It was a lousy fix. It wouldn’t work for the next thing that needed to be done, either, but they would probably hire one more person to write another layer of connecting code. But it was cheap (for them). And it worked (for the moment).”
Read the article at medium.com.