> I don't buy this whole "nobody knows how to update the code" reasoning
As an anecdote, your example demonstrates the truth of the reasoning. Absent extraordinary or unorthodox effort, such as patching the executable manually, programs do suffer from loss of understanding. Yes, you made it work, but can you really claim to understand the program and how it was written?
Of course, given enough time and effort, most code can be reverse engineered to a level of understanding good enough to work on it. In practice, most organizations are going to decide it's better to spend time and money on a replacement.
> I'm sure the source code wasn't lost, it would have been on a tape backup that people were too lazy to try and recover.
That's certainly one, rather uncharitable, way to look at it. But what constitutes sufficient effort, given time and money constraints in the real world? Unless that backup literally contained the only copy of information essential to the continued existence of the company, there's a limit. And what if they did find the backup, but it was on a magnetic medium that had degraded to unreadability?
I've made my career working on legacy code. There are definitely ways to understand systems even when nobody who originally worked on them is around, but business constraints have always determined whether or not the effort proceeds or is abandoned.
As an anecdote, your example demonstrates the truth of the reasoning. Absent extraordinary or unorthodox effort, such as patching the executable manually, programs do suffer from loss of understanding. Yes, you made it work, but can you really claim to understand the program and how it was written?
Of course, given enough time and effort, most code can be reverse engineered to a level of understanding good enough to work on it. In practice, most organizations are going to decide it's better to spend time and money on a replacement.
> I'm sure the source code wasn't lost, it would have been on a tape backup that people were too lazy to try and recover.
That's certainly one, rather uncharitable, way to look at it. But what constitutes sufficient effort, given time and money constraints in the real world? Unless that backup literally contained the only copy of information essential to the continued existence of the company, there's a limit. And what if they did find the backup, but it was on a magnetic medium that had degraded to unreadability?
I've made my career working on legacy code. There are definitely ways to understand systems even when nobody who originally worked on them is around, but business constraints have always determined whether or not the effort proceeds or is abandoned.