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by 082349872349872
1400 days ago
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The difference as I see it: computer science (sorry, "informatics") is a mathematical discipline, and hence tends to concern itself with, out of a given class, the minimal (and maximal, when existent) object(s). Programming is an engineering discipline, and hence tends to concern itself with, out of a given class, the intervals within that lattice that are optimal by some suitability function. In principle, the suitability function would be evaluated over the entire lattice; in practice, that function, whether explicitly or implicitly, includes a strong weight for "distance from existing solutions". In either case, this split in focus between the interior and the boundaries of the solution space means that programmers are often highly concerned with specific details that do not even appear (because they have been abstracted away) in the objects with which informaticians work. As an example: theory people love to use 1-ary trees (induction steps cost nothing in proofs, but cases are expensive) and they will use 2-ary trees (sometimes even without pressure to sympathize with the machine) but systems people and programmers use k-ary trees (where, if it's been determined by measurement and not by compatibility, k depends upon "the" bandwidth-delay product between the storage hierarchy levels for which the tree is optimized ... or at least what the bandwidth-delay product had been at the time of writing). |
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FWIW, when I was poking around last night looking for references for the "forced to get a Mac" story I found this.
Tony Hoare:
> The first time I visited Edsger in Eindhoven was in the early Seventies. My purpose was to find out more about the THE operating system, [Dijkstra, May 1968.] which Edsger had designed. In the computing center at which the system was running I asked whether there was really no possibility of deadlock. "Let's see" was the answer. They then input a program with an infinite recursion. After a while, a request appeared at the operator's console for more storage to be allocated to the program, and this was granted. At the same time they put a circular paper tape loop into one of the tape readers, and this was immediately read into buffer file by the spooling demon. After a while the reader stopped; but the operator typed a message forcing the spooler to continue reading. At the same time even more storage was allocated to the recursive program. After an interval in which the operator repeatedly forced further foolish storage allocations, the system finally ground to a complete halt, and a brief message explained that storage was exhausted and requested the operator to restart operations.
> So the answer was YES; the system did have a possibility of deadlock. But what interested me was that the restart message and the program that printed it were permanently resident in expensive core storage, so that it would be available even when the paging store and input/output utilities were inoperative. And secondly, that this was the very first time it had happened. I concluded that the THE operating system had been designed by a practical engineer of high genius. Having conducted the most fundamental and far-reaching research into deadlock and its avoidance, he nevertheless allocated scarce resources to ensure that if anything went wrong, it would be recognized and rectified. And finally, of course, nothing actually ever did go wrong, except as a demonstration to an inquisitive visitor.
https://history.computer.org/pioneers/dijkstra.html