Jury-Law books

"You could examine all sorts of status
about another program in a very clean, well-specified way."
Using this feature, Stallman was able to watch how
programs written by hackers processed instructions as
they ran. Another favorite feature would allow the
monitoring program to freeze the monitored program's
job between instructions. In other operating systems,
such a command would have resulted in half-computed
gibberish or an automatic systems crash. In ITS, it
provided yet another way to monitor the step-by-step performance.
"If you said, `Stop the job,' it would always be
stopped in user mode. It would be stopped between two
user-mode instructions, and everything about the job
would be consistent for that point," Stallman says. "If
you said, `Resume the job,' it would continue properly.
Not only that, but if you were to change the status of
the job and then change it back, everything would be
consistent. There was no hidden status anywhere."
By the end of 1970, hacking at the AI Lab had become a
regular part of Stallman's weekly schedule.


Pages:
89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113