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Groups > comp.sys.acorn.misc > #5937

Re: Unipod query

From "David Holden" <SpamBin@apdl.co.uk>
Newsgroups comp.sys.acorn.misc
Subject Re: Unipod query
Date 2012-07-26 08:34 +0000
Organization APDL
Message-ID <a7cdovFtmqU1@mid.individual.net> (permalink)
References <52b09af13ccvjazz@waitrose.com> <a07fe6b452.old_coaster@old_coaster.yahoo.co.uk>

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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.

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.

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.

-- 
David Holden  -  APDL  -  <http://www.apdl.co.uk>

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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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