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Re: Raspberry Pi 1Tbyte hard drive kit

From "James Harris" <james.harris.1@gmail.com>
Newsgroups comp.sys.raspberry-pi
Subject Re: Raspberry Pi 1Tbyte hard drive kit
Date 2015-09-12 11:41 +0100
Organization A noiseless patient Spider
Message-ID <mt0vdp$hq3$1@dont-email.me> (permalink)
References (2 earlier) <FYDIx.283815$zk7.22241@fx26.am4> <msv2b1$o93$1@dont-email.me> <cCFIx.320763$GG3.8135@fx10.am4> <msvmkf$853$1@dont-email.me> <mt0947$irb$1@dont-email.me>

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"David Taylor" <david-taylor@blueyonder.co.uk.invalid> wrote in message 
news:mt0947$irb$1@dont-email.me...

..

> Actually, when testing with PCs I have found that USB 3.0 devices 
> often perform faster than USB 2.0 devices even when plugged into the 
> sane USB 2.0 port.  Perhaps they are faster internally, perhaps there 
> is less overhead in the interface, or whatever.   Speed tests can and 
> do show an advantage.  Check for yourself.

Do you have a particluar way of doing such speed tests or a certain 
piece of software that you trust to give good figures?

I ask because I don't think a simple data transfer is enough. IME the 
speed of a disk varies a lot between outer and inner cylinders. For 
example,

  http://miscel.wikidot.com/disk-throughput

That particular disk averaged (using long 1-minute averages) about 
80Mbyte/s on the outer cylinders and 40Mbyte/s on the inner. So SDTRs 
(sustainable data transfer rates) can vary by a factor of 2 depending 
simply on which part of the disk surface is being accessed.

Added to that, short-term averages could show figures significantly 
higher or lower as they interact with things like the disk drive's 
inbuilt buffer memory, how a file is laid out on disk (the above graph 
was from disk-order sector access), other loads, remapped sectors, and 
drive autonomous operations.

James

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Thread

Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-10 22:56 +0100
  Re: Raspberry Pi 1Tbyte hard drive kit ray carter <ray@zianet.com> - 2015-09-10 22:24 +0000
    Re: Raspberry Pi 1Tbyte hard drive kit mrbrad <lostgonzo@gmail.com> - 2015-09-10 23:36 -0500
      Re: Raspberry Pi 1Tbyte hard drive kit mrbrad <lostgonzo@gmail.com> - 2015-09-19 23:23 -0500
        Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-20 00:42 -0400
          Re: Raspberry Pi 1Tbyte hard drive kit mrbrad <lostgonzo@gmail.com> - 2015-09-20 01:56 -0500
    Re: Raspberry Pi 1Tbyte hard drive kit mm0fmf <none@mailinator.com> - 2015-09-11 18:13 +0100
      Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-11 18:19 +0100
        Re: Raspberry Pi 1Tbyte hard drive kit mm0fmf <none@mailinator.com> - 2015-09-11 20:05 +0100
          Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-11 17:55 -0400
          Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-12 00:05 +0100
            Re: Raspberry Pi 1Tbyte hard drive kit David Taylor <david-taylor@blueyonder.co.uk.invalid> - 2015-09-12 05:21 +0100
              Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-12 11:41 +0100
                Re: Raspberry Pi 1Tbyte hard drive kit David Taylor <david-taylor@blueyonder.co.uk.invalid> - 2015-09-12 13:17 +0100
                Re: Raspberry Pi 1Tbyte hard drive kit Rob Morley <nospam@ntlworld.com> - 2015-09-12 15:28 +0100
            Re: Raspberry Pi 1Tbyte hard drive kit mm0fmf <none@mailinator.com> - 2015-09-12 08:22 +0100
              Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-12 03:30 -0400
            Re: Raspberry Pi 1Tbyte hard drive kit Mike Fleming <{mike}@tauzero.co.uk> - 2015-09-12 09:02 +0100
              Re: Raspberry Pi 1Tbyte hard drive kit mm0fmf <none@mailinator.com> - 2015-09-12 09:11 +0100
                Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-12 04:19 -0400
  Re: Raspberry Pi 1Tbyte hard drive kit David Taylor <david-taylor@blueyonder.co.uk.invalid> - 2015-09-11 07:21 +0100
    Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-16 18:59 +0100
      Re: Raspberry Pi 1Tbyte hard drive kit ray carter <ray@zianet.com> - 2015-09-16 19:23 +0000
  Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-11 13:30 -0400
    Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-16 19:02 +0100
      Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-16 14:23 -0400
        Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-16 19:42 +0100
          Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-16 15:37 -0400
            Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-16 20:54 +0100
              Re: Raspberry Pi 1Tbyte hard drive kit rickman <gnuarm@gmail.com> - 2015-09-16 16:41 -0400
          Re: Raspberry Pi 1Tbyte hard drive kit Martin Gregorie <martin@address-in-sig.invalid> - 2015-09-16 19:42 +0000
            Re: Raspberry Pi 1Tbyte hard drive kit "James Harris" <james.harris.1@gmail.com> - 2015-09-16 21:06 +0100
              Re: Raspberry Pi 1Tbyte hard drive kit Martin Gregorie <martin@address-in-sig.invalid> - 2015-09-16 21:19 +0000

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