If you read his article - mainly message passing and consequent context switching. Most programs with protected memory - thats anything after windows ME in the

If you read his article - mainly message passing and consequent context switching. Most programs with protected memory - thats anything after windows ME in the windows world, incl. win 98, 95 for example (ie not just ms dos) - don't need too much message passing. Stuff like webservers do (hence the perf advantage of nginx over apache, until they brought mod_event). Heck even web browsers do quite a bit despite his point - they do what they can to send as few messages as possible to compensate.