Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!lll-lcc!pyramid!csg From: csg@pyramid.UUCP Newsgroups: comp.arch Subject: Re: new Gould NPL Message-ID: <1813@pyramid.UUCP> Date: Thu, 2-Apr-87 01:54:56 EST Article-I.D.: pyramid.1813 Posted: Thu Apr 2 01:54:56 1987 Date-Received: Sat, 4-Apr-87 11:20:05 EST References: <501@sw1e.UUCP> <1805@pyramid.UUCP> <706@brl-sem.ARPA> Reply-To: csg@pyramid.UUCP (Carl S. Gutekunst) Organization: Pyramid Technology Corp., Mountain View, CA Lines: 28 Keywords: gould supermini Summary: How much bus do you need for I/O? In article <706@brl-sem.ARPA> ron@brl-sem.ARPA (Ron Natalie ) writes: >Last time I checked (and I checked Pyrmaid recently) Arete, Pyramid, and >Elxsi were not 12 MIPs. I had understood the poster to say that *two* processors gave 12 MIPS, which would make it about the same as Pyramid's 9820 dual CPU system. It has been since pointed out to me that it was 12 MIPS per CPU, which is a very different story; $400K would buy you 24MIPS or so. Elxsi claims 10MIPS per CPU, Pyramid 7, and Arete 2.5, and so on. >The bus on the new Gould is much faster than every CPU you listed. Elxsi's bus is claimed to be 330Mbytes/second, more than double the Gould NPL. (Pyramid's is 40MB.) Elxsi uses that huge bandwidth primarilly for multiple processors, and indeed it is the Pyramid's bus bandwidth that limits the number of CPUs you can throw on it. (Caching helps a lot, but the CPUs do need to reference main store once in a while. :-)) I'd be curious to hear people's thoughts on whether all that bandwidth is really usable by I/O. The best disks/controllers you can buy today only putter along at, what, 20Mbytes/sec? And the Unix file system is two slow and grody to really take advantage of more than about an eighth of that with a 12 MIPS CPU behind it. Yes, there's raw disk I/O, but how much is that used outside of dedicated database applications? (Honest questions, I really don't know. I'm just a comm hacker. :-))