Hard Drive data rates

Karl Larsen k5di at zianet.com
Fri Sep 28 21:55:52 UTC 2007


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.



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


-- 

	Karl F. Larsen, AKA K5DI
	Linux User
	#450462   http://counter.li.org.




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