Honneywell multics? from panels. the inline phots in this message folks -smecc

David Bridgham dab at froghouse.org
Thu Mar 17 14:15:41 CDT 2016


On 03/17/2016 11:59 AM, Noel Chiappa wrote:

>     > Each segment
>     > is in it's own address space; any memory reference was, per force, a
>     > segment number and offset.
>
> In this last sentence, is that referring to Multics?
>
> If so, that is exactly how the x86 _hardware_ works, 

He might have been referring to how the GE processor mapped each segment
to physical memory on its own while the x86 maps the segments into a
single 2^32 byte linear address space first and then maps that to
physical memory.  The x86 got this one wrong, in my opinion, as it means
you can't have full-sized segments if you have more than one effective
segment.  Or if you can do it, it's going to be a painful process of
keeping multiple versions of the segment table that maps in different
windows of the full-sized segment you're trying to access.




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