[Virtualacorn-list] MDF for 2560x1440 pixel monitor

David J. Ruck druck at druck.org.uk
Mon Nov 4 08:01:36 GMT 2013

On 03/11/2013 16:13, T.O.M.S. wrote:
> On Sun Nov 3 13:41:25 GMT 2013 David J. Ruck druck at druck.org.uk sayeth:
>> Just reduce the 1600 to 1440, as VRPC will use the PC mode of the
>> same resolution, and ignore the actual timing information.
> Thanks David. Tried that (albeit on a PC with a resolution limit of
> 1920x1200 pixels*) but unfortunately it reverts to the default state of
> 800x600 pixels which cannot be changed. I'm floundering on this but I
> sense the secret is in calculating the appropriate pixel rate - which is
> well beyond my ken

I don't think you can select a resolution on VRPC grater than the PC can 
do natively.

> But for my understanding, are you saying that as the underlying Big iMac
> has a native screen mode of 2560x1440 pixels, then VirtualRPC/RISC OS
> will pick that up, even if the (197000) pixel rate in the RISC OS MDF is
> inappropriate?

Yes, it doesn't try to use all the information in the MDF, just the 

> * Bearing in mind that mohsen's RISC OS MDF for an enormous 2560x1600
> pixels works fine in 16M colours on the same PC/monitor.)
>> You will have to change to using the ARM7500 emulation, as the
>> StrongARM one emulates the limitation of 2MB of VRAM of the
>> Risc PC.
> It's 8MB 'VRAM' for the StrongARM and ARM610 cores on the PC variants of
> VirtualRPC, but again for my understanding, is it only 2MB for the Mac
> variant please?

Sorry, the 8MB VRAM emulation was introduced in VRPC-SA which I didn't 
upgrade to, and as far as I know VRPC-SA is the same on Mac as PC. 
2560x1440 can be done in 8MB at 32K (or the slightly iffy 64K on RO6), 
but 16M needs the ARM7500 emulation.

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

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