I wish I could find the part written by J.E. Robertson. I took several graduate level courses from him as an undergraduate in the mid '60s. He became the world expert on division. He found that if you recoded to the redundant base -1, 0, 1 then number encodings could be found that had lots of zeros which he could optimize over and speed the division up. There were other sequential configurations he did special things with as well. You wouldn't believe the amount of theory he deduced from studying the redundant encoding problem and its application. The result was SRT division. He was the R and I can't remember who S and T were.<p>SRT division was implemented in the Illiac II.
Bitsavers.org Link (where there is even more cool stuff):<p><a href="http://bitsavers.trailing-edge.com/pdf/univOfIllinoisUrbana/illiac/ILLIAC/ILLIAC_programming_Sep56.pdf" rel="nofollow">http://bitsavers.trailing-edge.com/pdf/univOfIllinoisUrbana/...</a>
The context:<p><a href="http://en.wikipedia.org/wiki/ILLIAC" rel="nofollow">http://en.wikipedia.org/wiki/ILLIAC</a><p>"ILLIAC I was built at the University of Illinois based on the same design as the ORDVAC. It was the first von Neumann architecture computer built and owned by an American university. It was put into service on September 22, 1952.<p>ILLIAC I was built with 2,800 vacuum tubes and weighed about 5 tons. By 1956 it had gained more computing power than all computers in Bell Labs combined. Data was represented in 40-bit words, of which 1024 could be stored in the main memory, and 12800 on drum memory."<p>The interesting information from the manual is that the computer had 40-bits fixied-point arithmetic, directly calculating only numbers between -1 and +1. If was certainly very demanding programming it.<p>Another interesting detail: the puritans still didn't influence the name of the number system, they write about "sexadecimal" coding, and interestingly use "0 1 2 3 4 5 6 7 8 9 K S N J F L." Why "K S N J F L"? I don't know.<p>And a really fascinating detail: it was not only punched tapes and stuff: it had a 256x256 pixels CRT as an output device too. Sample on pg. 12-9
Reading this manual really brought me back to the time when being a programmer was probably closely tied to being a mechanic of the machine. We take computing for granted today but it must have been amazing to see first-hand how physical inanimate objects come together to build intelligence.
Mirror on archive.org: <a href="https://archive.org/details/bitsavers_univOfIlliIACILLIACprogrammingSep56_10672625" rel="nofollow">https://archive.org/details/bitsavers_univOfIlliIACILLIACpro...</a> (as the Dropbox link is down)
Dropbox is returning a 509 status code on the file, but I can't wait to take a look at this. My interest in this specific machine comes from its important place in the history of computer music with Lejaren Hiller's Illiac Suite:<p><a href="https://www.youtube.com/watch?v=n0njBFLQSk8" rel="nofollow">https://www.youtube.com/watch?v=n0njBFLQSk8</a>
<a href="http://ems.music.uiuc.edu/history/illiac.html" rel="nofollow">http://ems.music.uiuc.edu/history/illiac.html</a>
<a href="https://en.wikipedia.org/wiki/Illiac_Suite" rel="nofollow">https://en.wikipedia.org/wiki/Illiac_Suite</a>
The Computer History Museum has a number of physical artifacts from the ILLIAC II, III and IV, including a number of the logic modules: metal chassis units that held from 3 to 8 vacuum tubes that performed a single function.<p><a href="http://www.computerhistory.org/collections/search/?s=illiac&t=objects&f=physicalobject" rel="nofollow">http://www.computerhistory.org/collections/search/?s=illiac&...</a>