Date: Sat, 8 Apr 95 22:56:20 MDT From: terry@cs.weber.edu (Terry Lambert) To: rgrimes@gndrsh.aac.dev.com (Rodney W. Grimes) Cc: taob@gate.sinica.edu.tw, freebsd-current@FreeBSD.org Subject: Re: Disk performance Message-ID: <9504090456.AA18008@cs.weber.edu> In-Reply-To: <199504081647.JAA15531@gndrsh.aac.dev.com> from "Rodney W. Grimes" at Apr 8, 95 09:47:37 am
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> > > Yes, IDE drives load the cpu down far more, as they not only have to > > > bcopy the bytes to and from user land, they also have to bcopy them > > > to and from the disk. > > > > I presume that EIDE drives and drivers that support DMA wouldn't > > suffer from this particular deficiency then. Sorry, I don't mean to > > pick your brains in public like this. I hope someone else is learning > > the basics of disk transfer too. :) > > EIDE drives that support mode 2 DMA would not suffer from this problem > if the FreeBSD drives also supported mode 2 DMA. Luckily all EIDE drives adhere to the same standard for mode 2 DMA. 8-). Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.
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