SBC-MediaGX

[Alex J Lennon]

> >>  >Another question: why is the BIOS extension area soo big as
> >>  >the extension itself is only about 14kB? The autoexec.bat file
> >>  >on the Arcom bootfloppy mentions that the extension was enlarged
> >>  >some time ago to 256KB in order to accomodate the Windows CE
> >>  >registry???
> >>  Don't know. I stuck with 256kB on my board for the same 
> reason you did. I 
> >>  don't think it's critical; what's the maximum size for a ROM 
> extension?
> >>   16kB?  32kB?
> 
> What is the erase zone size on that board?  You would need to 
> reserve space in erase zone sized chunks; On a flash part with 
> 128KB erase zones, the minimum you would need to reserve would be 
> 128KB, no matter how large your BIOS extensions are.  You do not 
> want the area that your BIOS extension is in being moved around 
> by FlashFX, or any wear leveling system as it would need to stay 
> put in the beginning of the flash -- The reason for 256k escapes 
> me at this moment, as I remember that the BIOS Extension for 
> FlashFx is probably 16kb, but I am sure they were using the other 
> area for CE related issues.  It may very well be that the first 
> 128k (or 64k) was reserved as a full sector to handle the 16kb 
> BIOS extension, and the rest was done for future growth.

True - The area at the start of the flash array is 256Kb to support
a non-volatile CE registry. No harm will come of you reducing
this to the erase zone size of 128kb (unless of course you'll
be wanting to run CE ;)


Alex 




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