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Groups > comp.sys.acorn.misc > #5940

Re: Unipod query

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On 26 Jul 2012, "David Holden" <SpamBin@apdl.co.uk> wrote:
> On 25-Jul-2012, Tony Moore <old_coaster@yahoo.co.uk> wrote:
>
> [results not reproduced for brevity]
>
> > The first group of tests show that, for byte access, IDEFS is, on
> > average, more than 60% _slower_ than ADFS.
> >
> > The second group of tests show that, for load/save operations, IDEFS
> > is, on average, about 50% faster than ADFS.
>
> The byte access speed increase is well known and is because ADFS has
> buffered byte read/write.

Thanks for the explanation.

> With our IDE interfaces we did address this with a version which had
> buffering and this was a bit faster than ADFS. However this caused
> problems with high speed access, and proved incompatible with DMA, so
> we reverted to unbuffered in/out. This gives maximum data transfer for
> larger files, i.e. 95% of stuff, and if someone is using a program
> which does a lot of byte access and which they use frequently then if
> maximum speed is important just put the data files for that program on
> an ADFS disc.

Where is likely to be the best location for !Boot?

> We did make a special buffered version with no DMA available at one
> time for people for whom this was the primary requirement.
>
> I presume similar problems were encountered by Simtec with the Unipod.
>
> BTW the results I get for larger file transfer on a Unipod are quite a
> bit faster than the ones you show.

Could the difference be explained by fragmentation? My IDEFS 40GB drive
is a mirror of the ADFS 40GB drive, and both are about 55% full, having
been in use for several years. I carried out the speed tests twice, each
time with near identical results.

Tony

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Thread

Unipod query Chris Newman <cvjazz@waitrose.com> - 2012-07-17 09:30 +0100
  Re: Unipod query "David Holden" <SpamBin@apdl.co.uk> - 2012-07-17 09:06 +0000
    Re: Unipod query Chris Newman <cvjazz@waitrose.com> - 2012-07-17 17:34 +0100
      Re: Unipod query Brian Carroll <bric-nospam@argonet.co.uk> - 2012-07-17 20:05 +0100
        Re: Unipod query Chris Newman <cvjazz@waitrose.com> - 2012-07-18 12:56 +0100
          Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-21 00:31 +0100
            Re: Resurrected RiscPC "David Holden" <SpamBin@apdl.co.uk> - 2012-07-21 05:39 +0000
              Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-21 12:29 +0100
                Re: Resurrected RiscPC "Dave Plowman (News)" <dave@davenoise.co.uk> - 2012-07-21 14:05 +0100
                Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-21 18:09 +0100
                Re: Resurrected RiscPC Russell Hafter News <see.sig@walkingingermany.invalid> - 2012-07-21 18:56 +0100
                Re: Resurrected RiscPC "Bruce Goatly" <ss4@goatly.co.uk> - 2012-07-21 19:19 +0100
                Re: Resurrected RiscPC "Dave Plowman (News)" <dave@davenoise.co.uk> - 2012-07-21 20:26 +0100
                Re: Resurrected RiscPC Stuart <Spambin@argonet.co.uk> - 2012-07-22 14:46 +0100
                Re: Resurrected RiscPC Russell Hafter News <see.sig@walkingingermany.invalid> - 2012-07-21 21:39 +0100
                Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-22 13:53 +0100
                Re: Resurrected RiscPC "Dave Plowman (News)" <dave@davenoise.co.uk> - 2012-07-22 15:09 +0100
                Re: Resurrected RiscPC Fred Bambrough <fred@[127.0.0.1]> - 2012-07-23 16:36 +0100
                Re: Resurrected RiscPC "Dave Plowman (News)" <dave@davenoise.co.uk> - 2012-07-21 20:22 +0100
                Re: Resurrected RiscPC Brian Howlett <news-spamtrap@brianhowlett.me.uk> - 2012-07-22 10:03 +0100
                Re: Resurrected RiscPC "Dave Plowman (News)" <dave@davenoise.co.uk> - 2012-07-22 11:09 +0100
              Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-23 11:29 +0100
                Re: Resurrected RiscPC John Sandford <lists@thesandfords.me.uk> - 2012-07-23 16:28 +0100
                Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-23 18:27 +0100
                Re: Resurrected RiscPC Steve Fryatt <news@stevefryatt.org.uk> - 2012-07-23 20:38 +0100
                Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-23 22:25 +0100
                Re: Resurrected RiscPC "David Holden" <SpamBin@apdl.co.uk> - 2012-07-24 06:03 +0000
                Re: Resurrected RiscPC spampling <spam.pling@btinternet.com> - 2012-07-24 07:49 +0100
                Re: Resurrected RiscPC Stuart <Spambin@argonet.co.uk> - 2012-07-24 12:23 +0100
                Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-24 21:08 +0100
                Re: Resurrected RiscPC Dave Higton <dave@davehigton.me.uk> - 2012-07-24 22:05 +0100
                Re: Resurrected RiscPC Chris Newman <cvjazz@waitrose.com> - 2012-07-24 22:36 +0100
  Re: Unipod query Tony Moore <old_coaster@yahoo.co.uk> - 2012-07-25 16:40 +0000
    Re: Unipod query "David Holden" <SpamBin@apdl.co.uk> - 2012-07-26 08:34 +0000
      Re: Unipod query "Dave Plowman (News)" <dave@davenoise.co.uk> - 2012-07-26 10:22 +0100
      Re: Unipod query Tony Moore <old_coaster@yahoo.co.uk> - 2012-07-26 10:15 +0000
    Re: Unipod query Chris Newman <cvjazz@waitrose.com> - 2012-07-26 10:22 +0100

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