Comment On The Program Accelerator

As a postgrad in the late '80s, Neil Bowers made some extra book money by acting as a helper in the computing lab. At the time, undergrads were all working on a grindingly slow VAX-11/780, and Neil and his fellow postgrads were posted there for hands-on help. This tended to be focused at the start of the year, when there were groups discovering Unix and programming for the first time.

One time, an Irish girl asked Neil for some help, saying that she couldn’t understand what was going on: she thought her program looked right, but for some reason, each time she ran it she got partial output, and varying amounts of output each time. The homework assignment she was working on involved writing a program that generated various values and wrote the results in ascii tabular form to a file.

Neil went over to her workstation and had a look at her source code. Everything looked fine. She showed him the file generated by her last run, and indeed, it looked truncated. Hmmm. "Ok," Neil asked, "can you run your program for me, so I can see what happens?".

She typed ./a.out and hit return. Her left hand darted to the keyboard and she hit Control-C. Neil was still mentally processing this when she cat'd the output, and turned to say, "See!" It did indeed contain partial output. Again.

"Um," he paused, "can you just run it again please?" Neil figured that he must have not seen right. But once again she typed ./a.out, hit return, then whap! she hit Control-C. Neil asked her why she hit Control-C every time she ran her program.

"Well," she said confidently, "I discovered that Control-C makes the % prompt come up quicker!"