Date: Mon, 24 Aug 1998 15:46:36 +0000 From: Mike Smith <mike@smith.net.au> To: Graeme Tait <graeme@echidna.com> Cc: freebsd-hardware@FreeBSD.ORG, info@boatbooks.com Subject: Re: UDMA Support Message-ID: <199808241546.PAA00910@dingo.cdrom.com> In-Reply-To: Your message of "Mon, 24 Aug 1998 12:37:50 MST." <35E1C10E.1AA3@echidna.com>
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> Mike Smith wrote: > > > > > Does FreeBSD have Ultra DMA support or will it have it? > > > > FreeBSD 3.0 supports IDE DMA. SCSI disks will give better performance > > in multiple-disk or high load scenarios. > > Assuming I'm running an Ultra ATA drive (IBM 7200 RPM 10GB or 14GB to be > specific) under 2.2.7, what benefits would the Ultra DMA support under > 3.0 bring, and under what conditions (read/write, file size etc.)? I/O transactions to/from the disk will consume (much) less CPU time. This is a win if you have more than one process active and not disk-bound (eg. a world build using -pipe, X server, etc.) Disk throughput is also higher on P6 and above because they do PIO poorly. -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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