[Virtualacorn-list] MDF for 2560x1440 pixel monitor

[David J. Ruck]

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 
resolution.

> * 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.

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