phys(2) history

[Joseph S. D. Yao]

In article <612 at unisoft.UUCP> paul at unisoft.UUCP (n) writes:
>	Someone suggested the PHYS(2) system call for accessing physical
>						+
>addresses from user processes. This is a Uniplus   'feature', not a System
>V 'feature'. Don't expect to see it in a port done by someone other than
>Unisoft. (Mind you it is a neat idea, just right for mapping in such things
>as bit mapped graphics, device registers, floating point boards .....)

Just to keep the record straight, it first appeared in PDP-11
UNIX, I believe V7 ["7th Edition" to revisionists], marked as
one of those things that wasn't guaranteed to be kept in future
releases.  While Unisoft is to be given credit for making it
work on other architectures and perpetuating it, they should
be careful about accidentally implying that they invented it.
I'm not sure whether phys(2) originated at AT&T or was adopted.

(Sidebar: "maus" shared memory is also a PDP-11 V7[?] feature
that was marked to disappear, and that others have picked up
and perpetuated.  I believe that one actually originated in
Vrieje Universitat ages ago.)
-- 

	Joe Yao		hadron!jsdy at seismo.{CSS.GOV,ARPA,UUCP}