Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!sdd.hp.com!elroy.jpl.nasa.gov!ames!haven!uvaarpa!murdoch!shamash!clc5q From: clc5q@shamash.cs.Virginia.EDU (Clark L. Coleman) Newsgroups: comp.arch Subject: Re: why is 33 MHz a popular number? Message-ID: <1990Dec1.152532.16888@murdoch.acc.Virginia.EDU> Date: 1 Dec 90 15:25:32 GMT References: <1990Nov28.030500.16103@mozart.amd.com> <11214@pt.cs.cmu.edu> <1554@ftc.framentec.fr> Sender: news@murdoch.acc.Virginia.EDU Reply-To: clc5q@shamash.cs.Virginia.EDU (Clark L. Coleman) Organization: University of Virginia Computer Science Department Lines: 25 In article <1554@ftc.framentec.fr> ndoduc@framentec.fr (Nhuan Doduc) writes: >ok, nothing magic about 33 (or really, 33.33) which is 1/30 or 25 = 1/40 or >20 = 1/50 ... but it seems that there is a reason for 4.77MHz on the good old >PC : the "usual" frequency for a certain communication port is 15.31MHz, thus >some other magic values: 7.16 and 9.54MHz that you may [find] on 8088 machines I guess I can't figure it out myself, so please tell me the relationships among the following numbers : 4.77 MHz 7.16 MHz 9.54 MHz 15.31 MHz The first three have the relationship as 2,3 and 4 times 2.385 MHz, so that is no problem. Deriving them all from 15.31 MHz is tough. So I assume you meant 14.31 MHz. So, what was the famous communications port that worked at 14.31 MHz, just for my own curiosity ? ----------------------------------------------------------------------------- "We cannot talk of freedom unless we have private property." -- Gavriil Popov, Mayor of Moscow, September 11, 1990. ||| clc5q@virginia.edu Brought to you by Super Global Mega Corp .com