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Comment by JorgeGT | Hacker News Reader

If anyone is wondering, the UNIVAC scientific system pictured at the end was able to hold the impressive capacity of ~55 kB of RAM: http://archive.computerhistory.org/resources/text/Remington_...

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12*1024 36-bits words, max, so exactly the same number of bits as in 54 kB. Clock frequency was 125kHz, it seems.

The drum stored 288MB.

Edit: under "Some Applications", the first item listed is "Missiles". That shows where the money was.

> The drum stored 288MB.

Where did you get that number? It seems awfully high for 1957.

The text makes it clear that capacity of the drum was 16384 12 bit "words", 196608 bits in total. The use of core memory was a big advance at that time. Previously the drums had been the main memory for that generation of machines, with optimal placement of code on the drum being seen as a major programming skill.

> with optimal placement of code on the drum being seen as a major programming skill.

I remember reading an article/blog post from a programer of that time detailing how he optimized some code by taking into account the physics of the drum (such as mechanical inertia, angular momentum, etc.). I don't know how to locate it now but it was amazingly low-level.

You may be thinking of the Story of Mel:

http://www.catb.org/jargon/html/story-of-mel.html

https://en.m.wikipedia.org/wiki/The_Story_of_Mel

The words are 36 bits. 3 12 bit characters (the analogue to a byte)

Wikipedia: "The size of the byte has historically been hardware dependent and no definitive standards existed that mandated the size – byte-sizes from 1[3] to 48 bits[4] are known to have been used in the past."

12 3 bit characters.

12 "character" words of 36 bits.

Oops. I misread it as 16,384 groups of 4096 words each.

And yes, the result should have made me wonder.

The drum stored 16384 36 bit words, equivalent to 72 * 1024 bytes (72 kb).

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