Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site terak.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!hao!noao!terak!doug From: doug@terak.UUCP (Doug Pardee) Newsgroups: net.arch Subject: Re: Cached vs uncached MMUs Message-ID: <666@terak.UUCP> Date: Tue, 6-Aug-85 12:20:47 EDT Article-I.D.: terak.666 Posted: Tue Aug 6 12:20:47 1985 Date-Received: Sat, 10-Aug-85 23:02:07 EDT References: <5374@fortune.UUCP> <268@gcc-bill.ARPA> <563@sftig.UUCP> Distribution: net Organization: Calcomp Display Products Division, Scottsdale, AZ, USA Lines: 11 > You pay to load the page table when you context switch with either system. > ... The reference to main memory to > load the DAT box cache line cost just as much as the reference to main > memory to load the page table entry. With the cached approach (IBM DAT or NS32082) you don't also have to pay for the instructions the CPU would have to execute to load a page table. Also, it takes one memory cycle to load the cache, not two (load/store). -- Doug Pardee -- CalComp -- {seismo!noao,decvax!noao,ihnp4}!terak!doug