Groups > comp.lang.java.programmer > #12308

Re: O.T. optimising file placement

Date	2012-02-24 20:31 -0500
From	Arne Vajhøj <arne@vajhoej.dk>
Newsgroups	comp.lang.java.programmer
Subject	Re: O.T. optimising file placement
References	(3 earlier) <f6fak7d0tf9tva9lqh0jtd6imjgm8u5oa3@4ax.com> <ji3q44$le1$1@news.albasani.net> <ji44tm$j5o$3@localhost.localdomain> <4f45a713$0$291$14726298@news.sunsite.dk> <ji6hcc$8j1$3@localhost.localdomain>
Message-ID	<4f4839ed$0$294$14726298@news.sunsite.dk> (permalink)
Organization	SunSITE.dk - Supporting Open source

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On 2/23/2012 6:16 PM, Martin Gregorie wrote:
> On Wed, 22 Feb 2012 21:40:19 -0500, Arne Vajhøj wrote:
>> Most OS'es support async IO.
>>
> Yes, I know, but its not relevant to a single-threaded process since its
> logic generally requires it to wait for a read or write to complete
> before it continues[1]. Hence my comment that this prevents head movement
> being optimized unless a lot of processes are active because there's only
> one outstanding IOP per process.
>
> [1] unless you're deliberately doing async i/o using poll() or
>      select() (in C) or nio (in Java), in which case the process is often
>      best regarded as a half-way house between single and multi-threaded
>      logic.

I am talking about deliberate not accidental async IO.

And you maybe consider it half singlethreaded half multithreaded,
but when there is only one thread it is usually just called
single threaded.

Arne

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O.T. optimising file placement Roedy Green <see_website@mindprod.com.invalid> - 2012-02-21 09:59 -0800
  Re: O.T. optimising file placement Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-02-21 18:05 -0800
  Re: O.T. optimising file placement Jeff Higgins <jeff@invalid.invalid> - 2012-02-21 21:41 -0500
    Re: O.T. optimising file placement Jeff Higgins <jeff@invalid.invalid> - 2012-02-21 23:23 -0500
      Re: O.T. optimising file placement Roedy Green <see_website@mindprod.com.invalid> - 2012-02-22 11:15 -0800
        Re: O.T. optimising file placement Jeff Higgins <jeff@invalid.invalid> - 2012-02-22 16:00 -0500
          Re: O.T. optimising file placement Jeff Higgins <jeff@invalid.invalid> - 2012-02-22 16:03 -0500
            Re: O.T. optimising file placement Gene Wirchenko <genew@ocis.net> - 2012-02-22 14:52 -0800
              Re: O.T. optimising file placement Jeff Higgins <jeff@invalid.invalid> - 2012-02-22 18:24 -0500
                Re: O.T. optimising file placement Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-02-22 17:10 -0800
                Re: O.T. optimising file placement Gene Wirchenko <genew@ocis.net> - 2012-02-22 20:02 -0800
        Re: O.T. optimising file placement Lew <noone@lewscanon.com> - 2012-02-22 14:27 -0800
          Re: O.T. optimising file placement Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-23 01:31 +0000
            Re: O.T. optimising file placement Arne Vajhøj <arne@vajhoej.dk> - 2012-02-22 21:40 -0500
              Re: O.T. optimising file placement Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-23 23:16 +0000
                Re: O.T. optimising file placement Patricia Shanahan <pats@acm.org> - 2012-02-23 16:22 -0800
                Re: O.T. optimising file placement Patricia Shanahan <pats@acm.org> - 2012-02-23 21:45 -0800
                Re: O.T. optimising file placement Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-24 20:21 +0000
                Re: O.T. optimising file placement Arne Vajhøj <arne@vajhoej.dk> - 2012-02-24 20:31 -0500
                Re: O.T. optimising file placement Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-25 13:15 +0000
            Re: O.T. optimising file placement Lew <noone@lewscanon.com> - 2012-02-23 16:39 -0800
              Re: O.T. optimising file placement Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-24 01:49 +0000
                Re: O.T. optimising file placement Lew <noone@lewscanon.com> - 2012-02-24 10:50 -0800
                Re: O.T. optimising file placement Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-24 23:59 +0000
              Re: O.T. optimising file placement Arne Vajhøj <arne@vajhoej.dk> - 2012-02-24 20:25 -0500
    Re: O.T. optimising file placement Roedy Green <see_website@mindprod.com.invalid> - 2012-02-22 10:54 -0800

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