Greg:
You might find <http://www.x86.org/articles/pmbasics/tspec_a1_doc.html>
an interesting read on Protected Mode Basics.
John O
Greg Haerr wrote:
>
> On Thursday, June 03, 1999 10:07 AM, Alan Cox [SMTP:[EMAIL PROTECTED]] wrote:
> : > : You then need a 386. 64K is the limit. The original work I did was designed
> : > : to be easy to run in 286 protected mode once you got rid of any BIOS
>interfaces.
> : > :
> : > Remind me - what then is the benefit of protected mode? Merely
> : > separate address spaces?
> :
> : You get two things in 286 protected mode
> :
> : 1. You take exceptions if you try and go out of your segments
> : 2. You get 16Mbytes of addressable ram
> :
> :
> So, basically, 286 protected mode still runs in 64k segments, and
> in order to address the additional memory on a per-process basis we need
> large code or large data segments through the compiler (far pointers). In this
> way, larger programs can be written.
>
> With bcc currently, there would be no benefit to the size of user programs
> run, just more could be run on ELKS, since ELKS could allocate more physical
> memory by allocating more DS descriptors covering physical memory...
>
> In addition, the user programs could be protected from the kernel and vice
> versa...
>
> Right?
>
> Greg
