Sherlock Holmes' famous quote, "Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth."
But, when something is "impossible", it's probably a "software defect" (bug).
When it really is "impossible", and not a bug, indeed it might just be improbable, but, alas, if there's more than one possible improbably explanation, which is true? Further, sometimes the improbable is a "feature". ; )
Regardless, it can often be difficult to tell the difference between a "software defect" and "feature", but Holmes' like, The Case of the Crashed Program . . .
Decades ago, when I was a contract programmer, about half a year after I finished a contract, I got a call, your program crashed - come back and fix it. As I had a fairly decent record for low defects in my code, one manager (to protect his identity will refer to as Manager Lestrade) at that business teased me by noting, ha, Sheerluck (to protect my identify), one of your programs actually crashed!
Well, I looked into it it, and my program did crash. During the post-mortem, for the prior two months my program had been sending to the syslog, it's running low on memory (it might have also noted how low - don't recall). The day of its "death", it ran out of memory. (Don't recall, for sure, whether when it hit zero memory it actually "crashed" or first logged something like "cannot continue, aborting processing".) In any case, I called what happened "a feature". I also suggested, in the future, operations might want to occasionally check if running programs are throwing any kind of warning messages. Also, in case of my program, if you had searched for the warning message, in my code, you would have found explicit comments about what to do to increase the memory allocation.
Lastly, I mentioned, if you're wondering why not just allow the program to have all the possible memory it can, first, although hopefully it would never need that much, there's still a limit, and if you hit that one, now what do you do? Second, while my program is acquiring all this memory, what's the impact to other programs running concurrently? (BTW, when memory is just acquired, without any kind of monitoring, whether done accidentally, or intentionally, you may obtain "memory leak" results.)
