pem.nu

Computer History

A lot has happened in the 32 years since I wrote my first program on a PDP-8...

To illustrate the development: In 1989 I wrote a C program which computes a perfect minimal hash table given a fixed set of keywords. (Based on an article by Richard J. Cichelli in CACM January 1980.) The interesting point with this is that I still have the program, and I have run the same test suite on most machines that have come in my way, starting with a Vax 750 and a DEC 2060 (which were old, but still around when I wrote the program). The test case which took the longest to run still takes measurable time. A few examples of running times (minutes:seconds) over the years:

Note that this is a CPU bound program which uses very little memory and does no disk I/O. The timings do not necessarily show the different systems' overall performance.

If I try to estimate the year of different machines (not exactly the ones above - the full list is about 30 machines) and plot a graph, you get something like this:

From half an hour to half a second in about 25 years, not bad. :)