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From: michaelv@MindBender.HeadCandy.com (Michael L. VanLoon)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: 2 swap devices: does it make sense?
Date: 17 Jan 1996 06:30:12 GMT
Organization: HeadCandy Associates... Sweets for the lobes.
Lines: 27
Message-ID: <MICHAELV.96Jan16223012@MindBender.HeadCandy.com>
References: <87u41zetl7.fsf@compi.hobby.nl> <4denac$re@vulture.dmem.strath.ac.uk>
<MICHAELV.96Jan16000702@MindBender.HeadCandy.com>
<4dg5tn$9f5@fu-berlin.de>
NNTP-Posting-Host: mindbender.seanet.com
In-reply-to: graichen@dirac.physik.fu-berlin.de's message of 16 Jan 1996 12:32:55 GMT
In article <4dg5tn$9f5@fu-berlin.de> graichen@dirac.physik.fu-berlin.de (Thomas Graichen) writes:
also two IDE drives (each on its own controller) are also better than one
Yes, this is true. And, it's a good solution if you're stuck with
IDE. Highly recommended, in fact, if you *can't* move to SCSI.
But, be aware that it still doesn't match SCSI performance. Even with
two IDE controllers, the CPU is still doing all the I/O in a busy
loop, and that's the difference. With a decent SCSI controller
(low-end SCSI boards will do CPU PIO like IDE), the SCSI board does
all the I/O while the CPU does other things.
Now, theoretically, with a true EIDE hard drive, controller, *and* a
fully capable driver, you could get asynchronous bus-master I/O like
with SCSI, but I don't think there are any really good drivers like
this available yet (are there?). And, this does mean you have to have
a *decent* EIDE controller that can do DMA by itself.
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Michael L. VanLoon michaelv@HeadCandy.com
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, HP300, Sun3, Sun4,
DEC PMAX (MIPS), DEC Alpha, PC532
NetBSD ports in progress: VAX, Atari 68k, others...
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