Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!cmcl2!phri!roy From: roy@phri.UUCP (Roy Smith) Newsgroups: comp.arch,comp.sys.misc,comp.unix.wizards Subject: Re: Between a Sun-4 and a Cray-2 Message-ID: <2869@phri.UUCP> Date: Sat, 22-Aug-87 21:09:03 EDT Article-I.D.: phri.2869 Posted: Sat Aug 22 21:09:03 1987 Date-Received: Sun, 23-Aug-87 14:48:55 EDT References: <7500@shemp.UCLA.EDU> <552@winchester.UUCP> <2866@phri.UUCP> Reply-To: roy@phri.UUCP (Roy Smith) Distribution: world Organization: Public Health Research Inst. (NY, NY) Lines: 24 Summary: Correction to my earlier Sun integer/floating speed ratio claim Xref: mnetor comp.arch:1871 comp.sys.misc:772 comp.unix.wizards:3841 In article <2866@phri.UUCP> I wrote: > the Sun-3/100, 3/200, and 4/200 series machines all use the same FPA, based > on the Wietek chip set. What that means is that the 3/100 series has the > "best" floating/integer speed ratio, and the 4/200 series the "worst". It has since been pointed out to me that while the first sentence is true, the second one is misleading, if not actually false. Yes, all three machines use the same FPA (not clear if it's actually the same board, or a similar board based on the same chip set), but on the 4/2xx machines, the integer cpu and the FPA are closer coupled than on the 3/2xx's, the 4/2xx has better (presumably this means faster) memory, and better compilers. All this adds up to a 1.5-2X increase in floating point speed. Personally, I think the "better compilers" reason is a crock since with appropriate effort, the 3/2xx could have better compilers too, but I can understand why Sun would want to devote more programmer time to working on the compilers for their new machines than for their old ones. On the other hand, since the Sun-4 series is a RISC machine, it's probably easier to write really good compilers for it (or at least, that's the theory), so maybe I'm being unfair (again :-)). -- Roy Smith, {allegra,cmcl2,philabs}!phri!roy System Administrator, Public Health Research Institute 455 First Avenue, New York, NY 10016