[iyonix-support] Re: Lazy Task Swapping on Iyonix/RISC OS 5.11

In message <4e3becd5c8lists-nospam@xxxxxxxxx>
          Paul Vigay <lists-nospam@xxxxxxxxx> wrote:

> In article <d80ce13b4e.rogerarm@xxxxxxxxxxxxxxxxxxx>,
>    Roger Darlington <rogerarm@xxxxxxxxxx> wrote:

> Indeed, I wonder what happens if two applications simultaneously decide to
> increase their wimpslots? Is there perhaps a clash, or mis-allocation of
> slot space or something?[*]

This is simple. In application space, nothing happens simultaneously 
in RISC OS. There is precisely one active task at any point, all the 
others are paged out and their memory is not even accessible.

>> However: I DID GET A CRASH: Several thumbnails in Variation were
>> corrupted with coloured pixels, and several thumbnails went completely
>> blank. The error message issued by Variation was: AODT at FC183290 code
>> 2935. I've no idea what that means.
> 
> My suspicion is that is might be something to do with [*] above.

It simply means "Abort on data transfer", i.e., an attempt to access a 
non-existing memory address. This does happen when accessing memory 
outside of the memory slot, but it is also the most typical symptom 
when an application's memory has been altered randomly and the altered 
memory happened to be a pointer. If you modify any C program's data 
space randomly, you will almost invariably end up with such an error.

> P.S. Ovation ignores its own wimpslot anyway, as on my copy it says;
> WimpSlot -min 1648K -max 1648K
> and I've just double-clicked on it to load, and immediately it comes up
> with 2392K in the task manager. If you start typing in a new document you
> can see the wimpslot value flickering in the task display, so it's
> obviously doing something to chunks of memory.

This is perfectly normal. The initial WimpSlot is only needed to get 
the executable into memory and run it. Then, as the executable creates 
data structures, loads default settings etc. it claims more memory.

Martin
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Martin Wuerthner           MW Software          lists@xxxxxxxxxxxxxxx
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