Making Electrons Count (part 10 of 11)

315 It is just about time to run my program.
316 My tape is inserted in the photoelectric reader,
317 and read into Whirlwind's storage element.
318 Note Computations are proceeding at the rate of about thirty thousand arithmetic operations per second, too fast to follow on the panel lights that show the moment-by-moment results of the calculations.
319 Apparently there is a mistake in my program. I suppose this is not unusual for new programmers. When a program fails, the computer has been programmed to furnish sufficient information to enable the programmer to trace the source and nature of his trouble. [splice] mistakes the programmer might otherwise have found only after several days of checking.

[Tape supervisor] The night's run's completed, the operator has returned all the forms and results to the tape preparation room. During the five hours available to the applications group each day, as many as one hundred programs may be run on the computer. Later we will file a copy of the performance results, film negatives, and tapes. A duplicate of the performance results is made available to the programmer.

Invariably, programmers attribute the initial unsuccessful performances of their programs to tape errors or to computer malfunctions. Sometimes they are right, but usually I can assure them that the tape contains no typographical errors.

Ordinarily, programmers are discouraged from taking tapes from the tape room, because of the possibilities of loss or damage to the tape.

321a, b, c, d Note Now back he goes to more studying and complete analysis of his difficulties.
322 During the past few days, with the aid of the information obtained in my first run, I have corrected several mistakes, some careless, some obscure. After a final check by my staff consultant, I shall be ready for another computer run. He agrees with my modifications and with my decision to run the program again after these modifications have been put on tape.

I'm beginning to feel like an old hand at this thing. But why must they run computers at four o'clock in the morning?

First the operator reads the main tape into the computer, and then he reads in the short tape which contains the modifications.


Say! What's going on here? Something must be wrong with the oscilloscope!

The operator advises me to face facts and check my program again.

Credits and Notice:

The MIT Museum has kindly granted permission for me to reproduce these extracts from the 1953 film on MIT Project Whirlwind,"Making Electrons Count." The permission is governed by an agreement between Daniel P. B. Smith and the MIT Museum, and covers publication at this Web site only. Individuals may view this material at this Web site, Any other use requires permission from the MIT Museum, 265 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307.

The original film credits contain no date or copyright notice and reads, in full:

The Digital Computer Laboratory of the Massachusetts Institute of Technology Presents "Making Electrons Count: Solving a Problem on M.I.T.'s Electronic Digital Computer 'Whirlwind I.' Sponsored by: Office of Naval Research. Physicist played by Dean N. Arden. Script by Edwin S. Kopley. Photographed and Directed by Lloyd G. Sanford.

--Daniel P. B. Smith,