🚀 go-pugleaf

In article <1990Feb22.034517.8676@esegue.segue.boston.ma.us> johnl@esegue.segue.boston.ma.us (John R. Levine) writes:

>The ROMP, actually its mmu chip which is named Rosetta, handles this pretty
>well despite having a reverse map page table with no provision for aliasing.
>The high four bits of a memory address are looked up in a tiny fast memory
>to get a segment number.  These segment numbers are global to the entire
>system.  The file mapping we put into AIX maps a file to a segment, so if you
>map a file into several processes there is no aliasing problem; they use the
>same segment.

The segment idea could have been built on top of any viable paging
scheme, and doesn't require the inverted scheme that was used.

The inverted table (+ hash table and chains) mostly gets in the way
when the software wants aliasing. Since the hardware designers knew
that AIX does aliasing, could you explain why they still went with
the inverted approach? I don't understand the net benefit, or any
benefit.
-- 
Don		D.C.Lindsay 	Carnegie Mellon Computer Science