[Virtualacorn-list] RO 5.20 on VRPC

[David J. Ruck]

On 08/01/2014 11:41, T.O.M.S. wrote:
> A wish for >256MB RAM is an interesting point though. In practice we
> never get even close to the limits with 256MB as we find that handling
> such enormous files would become so unwieldy that it's much better to
> split the files into smaller and more manageable sub-sets. That also
> avoids the risk of hitting the buffers of the 26-bit limit of
> (typically) 30MB.

The subject line indicates running RISC OS 5.20, which doesn't have the 
26bit limit of 28MB for the application slot, and allows a single task 
to use all the free memory in the machine in its slot.

Running ported command line processes which handle a vast amount of data 
is the only time I've used more than 256MB of the 512MB in my Iyonix. 
Even manually stitching together half a dozen 7mpix images in Photodesk 
takes less than 256MB. (Incidentally Photodesk can be set to use a DA 
with a maximum size, or the application slot up to as much memory is free).

You should note that giving RISC OS 5 over 256MB, the address space 
allocated to dynamic areas is reduced to allow the application slot to 
grow up to the maximum RAM. There is a command to limit applications 
asking for dynamic area up to the size of the RAM, to a smaller amount 
such as 128MB. But there are only so many 128MB blocks available, so 
tuning apps such as Messenger to use 64MB for Messaenger and MsgServe is 
advisable.

If you upgrade to 1GB (the maximum of physical memory that the IOP321 in 
the Iyonix supports), the issue with the RISC OS dynamic area pool 
shrinking is even worse. It would of course be the same if you could 
allocate 1GB to VRPC, but I don't think its MEMC emulation supports over 
256MB. More than 256MB was possible in a Risc PC, but only by using 
Castle's Kinetic StrongARM card, which had its own on board fast RAM, 
accessed independantly of the MEMC.

Cheers
-- 
David J. Ruck
email: druck at druck.org.uk
phone: +44(0)7974 108301