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5.2.2 Application-driven Development

We began to build algorithms and methods to exploit the power of parallel computers. With little difficulty, we were able to develop algorithms for solving partial differential equations [Brooks:82b], FFTs  [Newton:82a], [Salmon:86b], and high-energy physics problems described in the last chapter [Brooks:83a].

As each person wrote applications, however, we learned a little more about the way problems were mapped onto the machines. Gradually, additional functions were added to the list to download and upload data sets from the outside world and to combine the operations of the rdELT and wtELT functions into something that exchanged data across a channel.

In each case, these functions were adopted, not because they seemed necessary to complete our operating system, but because they fulfilled a real need. At that time, debugging  capabilities were nonexistent; a mistake in the program running on the nodes merely caused the machine to stop running. Thus, it was beneficial to build up a library of routines that performed common communication functions, which made reinventing tools unnecessary.

Guy Robinson
Wed Mar 1 10:19:35 EST 1995