14 Jul
2015
14 Jul
'15
7:09 a.m.
On Jul 13, 2015, at 8:52 PM, Johnny Billquist <bqt
at update.uu.se> wrote:
On 2015-07-13 21:16, Rich Alderson wrote:
To me, ?segment? means a chunk of memory. It doesn?t refer to separate page tables, or
page tables broken into pieces. And as I recall, the terms ?instruction and data
segments? were in common use to describe the feature.
The PDP-11 is a bit unusual in that each page is *up to* 8k, the actual size (and whether
it?s the lower or the upper part that is accessible) is specified by the page description
register for that page. Also in that the physical address of the page isn?t constrained
to a multiple of the (max) page size.
paul
...
[2] With memory management, 18 or 22, in 16-bit
segments. Late models could
use separate instruction and data segments, for a total of 128KB in use at
one time.
??? What segments??? The PDP-11 have a plain simple page table. No segments anywhere in
sight. And each page is 8K.