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Groups > comp.sys.acorn.programmer > #1496

Re: OS_GBPB 12 in a Wimp task

Date 2012-03-12 11:56 +0000
From Gavin Wraith <gavin@wra1th.plus.com>
Newsgroups comp.sys.acorn.programmer
Subject Re: OS_GBPB 12 in a Wimp task
Message-ID <5fa2466f52.wra1th@wra1th.plus.com> (permalink)
References (5 earlier) <almarsoft.5374763469681712868@news.orange.fr> <8299b36e52.Matthew@sinenomine.freeserve.co.uk> <almarsoft.6587021169203963779@news.orange.fr> <d670e66e52.wra1th@wra1th.plus.com> <almarsoft.8991976711320644983@news.orange.fr>
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In message <almarsoft.8991976711320644983@news.orange.fr>
          Rick Murray <heyrickmail-usenet@yahoo.co.uk> wrote:

> Your app does a partial OS_GBPB to read an epic list of files (say, 
> the contents of a well stocked manga scanlation folder). For speed, 
> it'll do them twenty at a time.
> 
> What happens if:
> 1. Something else does an OS_GBPB, especially if within the same 
> directory structure?
> 
> 2. The list of files *changes* in between polls, like you're counting 
> and moving the same stuff at the same time?
> 
> While you as an application need to keep track of your own state, the 
> filesystem hands you a value in R4 of OS_GBPB 12 which may not be 
> valid at some indeterminate time in the future...

I do not think we are in disagreement. I cannot see how any filing
operations (or access to any mutable shared resource) can be 
multitasked unless there is some locking semaphore. I do not know what 
RISC OS does about this. Can anybody more knowledgeable give a quick answer?

-- 
Gavin Wraith (gavin@wra1th.plus.com)
Home page: http://www.wra1th.plus.com/

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Thread

OS_GBPB 12 in a Wimp task Christopher Bazley <cs99cjb@gmail.com> - 2012-03-06 14:33 -0800
  Re: OS_GBPB 12 in a Wimp task jeff <jeffrey.a.doggett@gmail.com> - 2012-03-07 00:02 -0800
    Re: OS_GBPB 12 in a Wimp task Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-03-08 22:33 +0000
      Re: OS_GBPB 12 in a Wimp task Christopher Bazley <cs99cjb@gmail.com> - 2012-03-10 10:22 -0800
        Re: OS_GBPB 12 in a Wimp task Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-03-10 21:04 +0000
          Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-10 23:11 +0100
            Re: OS_GBPB 12 in a Wimp task Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-03-11 09:10 +0000
              Re: OS_GBPB 12 in a Wimp task Chris Johnson <chrisjohnson+news@spamcop.net> - 2012-03-11 10:41 +0000
              Re: OS_GBPB 12 in a Wimp task Steve Fryatt <news@stevefryatt.org.uk> - 2012-03-11 11:06 +0000
              Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-11 17:56 +0100
                Re: OS_GBPB 12 in a Wimp task Gavin Wraith <gavin@wra1th.plus.com> - 2012-03-11 18:25 +0000
                Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-12 00:33 +0100
                Re: OS_GBPB 12 in a Wimp task Gavin Wraith <gavin@wra1th.plus.com> - 2012-03-12 11:56 +0000
                Re: OS_GBPB 12 in a Wimp task Martin Wuerthner <spamtrap@mw-software.com> - 2012-03-12 16:44 +0100
                Re: OS_GBPB 12 in a Wimp task druck <news@druck.org.uk> - 2012-03-12 20:57 +0000
                Re: OS_GBPB 12 in a Wimp task Martin Wuerthner <spamtrap@mw-software.com> - 2012-03-12 22:26 +0100
                Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-13 17:50 +0100
                Re: OS_GBPB 12 in a Wimp task jgharston <jgh@arcade.demon.co.uk> - 2012-03-13 10:15 -0700
                Re: OS_GBPB 12 in a Wimp task Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-03-13 07:34 +0000
                Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-14 06:00 +0100
                Re: OS_GBPB 12 in a Wimp task Christopher Bazley <cs99cjb@gmail.com> - 2012-03-15 02:40 -0700
                Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-15 14:55 +0100
                Re: OS_GBPB 12 in a Wimp task "Ste (news)" <steve@revi11.plus.com> - 2012-03-15 14:46 +0000
                Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-15 18:44 +0100
                Re: OS_GBPB 12 in a Wimp task Jeremy Nicoll - news posts <jn.nntp.scrap007@wingsandbeaks.org.uk> - 2012-03-15 19:44 +0000
                Re: OS_GBPB 12 in a Wimp task Alan Adams <alan@adamshome.org.uk> - 2012-03-15 20:36 +0000
                Re: OS_GBPB 12 in a Wimp task Chris Johnson <chrisjohnson+news@spamcop.net> - 2012-03-15 20:26 +0000
                Re: OS_GBPB 12 in a Wimp task Rick Murray <heyrickmail-usenet@yahoo.co.uk> - 2012-03-16 06:12 +0100
                Re: OS_GBPB 12 in a Wimp task Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-03-15 20:34 +0000
                Re: OS_GBPB 12 in a Wimp task Alan Adams <alan@adamshome.org.uk> - 2012-03-15 21:04 +0000
                Re: OS_GBPB 12 in a Wimp task Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-03-16 00:17 +0000
        Re: OS_GBPB 12 in a Wimp task Chris Johnson <chrisjohnson+news@spamcop.net> - 2012-03-10 23:58 +0000
          Re: OS_GBPB 12 in a Wimp task Chris Johnson <chrisjohnson+news@spamcop.net> - 2012-03-11 10:43 +0000
          Re: OS_GBPB 12 in a Wimp task jeff <jeffrey.a.doggett@gmail.com> - 2012-03-12 03:03 -0700
            Re: OS_GBPB 12 in a Wimp task Chris Johnson <chrisjohnson+news@spamcop.net> - 2012-03-12 10:44 +0000
            Re: OS_GBPB 12 in a Wimp task Matthew Phillips <spam2011m@yahoo.co.uk> - 2012-03-13 07:44 +0000
              Re: OS_GBPB 12 in a Wimp task jeff <jeffrey.a.doggett@gmail.com> - 2012-03-13 03:06 -0700
  Re: OS_GBPB 12 in a Wimp task druck <news@druck.org.uk> - 2012-03-07 10:08 +0000

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