Hard Drive data rates
Aaron Konstam
akonstam at sbcglobal.net
Sat Sep 29 13:20:09 UTC 2007
On Fri, 2007-09-28 at 15:55 -0600, Karl Larsen wrote:
> Aaron Konstam wrote:
> > On Fri, 2007-09-28 at 12:07 -0700, John Wendel wrote:
> >
> >> Lamar Owen wrote:
> >>
> >>> On Friday 28 September 2007, Karl Larsen wrote:
> >>>
> >>>> I was lead to mis-understand the data rate of my new SATA hard
> >>>> drive. It indicated that the data rate was 3 GB/sec. But some checking
> >>>> with Google said the Hard Drive makers are very free with their units.
> >>>> To be specific a SATA drive is 3000 MegaBits/second. This boils down to
> >>>> about 375 MB.
> >>>>
> >>> Due to the 8B/10B coding used in SATA, you can divide the bitrate by ten and
> >>> not eight to get the byterate. Thus, 3Gb/s is 300MB/s at the wire. The
> >>> semi-standard way of differentiating between bits per second and bytes per
> >>> second in specs is to use a lower-case b for bits, and an upper-case B for
> >>> bytes, but unfortunately not everyone follows that.
> >>>
> >> Your talking about the wire speed. The REAL speed is determined by the
> >> disk drive. You're lucky to get 75MB/s with a desktop drive.
> >>
> >> Regards,
> >>
> >> John
> >>
> > Try hdparm -T and hdparm -t
> >
> These just list what the file hdparm can do in very brief terms. And #
> hdparm is not working at all well on my F7.
>
What does hdparm return when you try it?
.
--
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The cost of living hasn't affected its popularity.
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Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam at sbcglobal.net
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