The Impossible Dream: Computing E to 116K Places with a Personal Computer [Woz]

Woz is rightly celbrated for his hardware designs, but, as this article shows, his software designs were also impressive. This article gives a clear derivation of some clever math and implementation techniques to compute e to over 100,000 places on a very limited 8-bit Apple 2 computer in the late 1970s.

Interesting quotes:

> I first calculated e to 47 K bytes of precision in January 1978. The program ran for 4.5 days, and the binary result was saved on cassette tape. Because I had no way of detecting lost-bit errors on the Apple (16 K-byte dynamic memory circuits were new items back then), a second result, matching the first, was required. Only then would I have enough confidence in the binary result to print it in decimal. Before I could rerun the 4.5 day program successfully, other projects at Apple, principally the floppy-disk controller, forced me to deposit the project in the bottom drawer. This article, already begun, was postponed along with it. Two years later, in March 1980, I pulled the e project out of the drawer and reran it, obtaining the same results. As usual (for some of us), writing the magazine article consumed more time than that spent meeting the technical challenges.

NOTE: The article of interest begins on page 392. I had linked to it directly, but the Hacker News site stripped the page number out of the URL, so now the link goes to the first page of the issue of BYTE magazine that contains the article.