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STORED PROGRAMS
From the begi
But more than a year before ENIAC was finished, indeed as early as the begi
To store a program inside of the machine, they would need to create a large memory capacity. Eckert considered many methods for doing that. “This programming may be of the temporary type set up on alloy discs or of the permanent type on etched discs,” he wrote in a January 1944 memo.39 Because such disks were not yet affordable, he proposed using instead, on the next version of ENIAC, a cheaper storage method, which was called an acoustic delay line. It had been pioneered at Bell Labs by an engineer named William Shockley (about whom there will be a lot more later) and developed at MIT. The acoustic delay line worked by storing data as pulses in a long tube filled with a thick and sluggish liquid, such as mercury. At one end of the tube, an electrical signal carrying a stream of data would be converted by a quartz plug into pulses that would ripple back and forth the length of the tube for a while. The ripples could be refreshed electrically for as long as necessary. When it came time to retrieve the data, the quartz plug would convert it back into an electrical signal. Each tube could handle approximately a thousand bits of data at one-hundredth the cost of using a circuit of vacuum tubes. The next-generation ENIAC successor, Eckert and Mauchly wrote in a memo in the summer of 1944, should have racks of these mercury delay line tubes to store both data and rudimentary programming information in digital form.
JOHN VON NEUMANN
At this point, one of the most interesting characters in the history of computing reenters the tale: John von Neuma
Von Neuma
Von Neuma
There is a wealth of stories about young von Neuma
In addition to school, he had private tutors in math and languages, and by age fifteen he had completely mastered advanced calculus. When the communist Béla Kun briefly took over Hungary in 1919, von Neuma
Von Neuma
Von Neuma
While at the Institute in the late 1930s, von Neuma