A Capacity Planning/Queueing Theory Primer or How Far Can You Go on the Back/Of/An/Envelope?

Most of the benefit of capacity planning for computer systems comes from applying common sense principles to easily understood (if not easily measured) data. If you can estimate business growth you need only simple arithmetic to figure out how busy your computer will be. But sometimes the fact that the system is subtle does matter: it’s hard to predict response times. Then you must use mathematics (instead of arithmetic) or software which knows some typically a package incorporating a queueing network model of your computer ∗This is a scanned version of a reprint of the original, converted to TEX. I wrote the paper while consulting for BGS Systems. The Computer Measurement Group probably owns the copyright, but the material is not available electronically. I doubt that they would object to this version.