Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!dcdwest!ittvax!decvax!genrad!teddy!panda!talcott!harvard!seismo!brl-tgr!tgr!chris@maryland From: chris@maryland (Chris Torek) Newsgroups: net.unix-wizards Subject: Re: How to make 4.2BSD ``/etc/dumps faster Message-ID: <6894@brl-tgr.ARPA> Date: Wed, 2-Jan-85 07:41:44 EST Article-I.D.: brl-tgr.6894 Posted: Wed Jan 2 07:41:44 1985 Date-Received: Fri, 4-Jan-85 04:38:32 EST Sender: news@brl-tgr.ARPA Organization: Ballistic Research Lab Lines: 13 I didn't like the pipes idea, so I wrote a ``mass driver'' device driver that runs other raw devices through their block interface. It manages to keep even the TU78 busy most of the time (125 ips at 6250 bpi, or 781K/sec) when run off Eagle disks in single user mode. I figured pipes would be fairly slow 'cause the network interface limits you to 2048 bytes per transfer (although you can increase it). This means that for a 10240 block write (like dump() uses) you need 5 pairs of context switches, which can beat a 750 into the ground pretty well. Also, it makes it harder to communicate success/failure statuses. Chris