Shadow RAM for BIOS

[pgd at bbt.se]

In article <107963 at convex.convex.com> langston at convex.COM (Kevin Langston) writes:
>
>I just learned that the Micronics 386/33 reserves the 384K chunk whether
>you tell it to use shadowing or not. I am running 386 Xenix 2.3 and I would
>like to know if there is any performance to be gained by using this memory
>for BIOS shadowing under a protected OS, or does Xenix duplicate the BIOS
>functionality some other way? 
>
>Thanks for any tips, suggestions, or meaningful explanations,

I don't think that is true. We have machines with four different
versions of Micronics motherboards. (one old TTL 20MHz, one newer
20Mhz, one TTL 25MHz, and some ASIC 25MHz) None of them reserve the
shadow RAM specially. So I find it very unlikely that a later model,
the 33MHz motherboard does that. They all have dip-switches to reserve
memory, but Xenix is ignoring all that, and is using all memory.

You can easily see how much memory Xenix is using, at boot time.
Compare that with the amount of memory you know you have in the machine.
(Check the "total memory" number)

Xenix is using the bios only for booting. After that it is completely
ignored. Everything the bios is doing, is done by the xenix kernel.