Re: Hard Drive data rates

[Aaron Konstam <akonstam sbcglobal net>]

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
--
=======================================================================
It is much easier to suggest solutions when you know nothing about the
problem.
=======================================================================
Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam sbcglobal net