Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: PDP-11 data and function address spaces (was External ptrs and arrays)
Message-ID: <1989Nov9.200332.8763@utzoo.uucp>
Organization: U of Toronto Zoology
References: <530@dftsrv.gsfc.nasa.gov> <225800239@uxe.cso.uiuc.edu> <11567@smoke.BRL.MIL> <20642@mimsy.umd.edu>
Date: Thu, 9 Nov 89 20:03:32 GMT

In article <20642@mimsy.umd.edu> chris@mimsy.umd.edu (Chris Torek) writes:
>... PDPs came in different models
>and had different operating systems that used different capabilities.
>One of the (somewhat less frequently used) capabilities was what was
>called `split I&D', in which each machine address had to be qualified
>with `instruction' or `data' before it was unique...

Dept. Of Really Fussy Nit-Picking:  relatively few pdp11s, and relatively
few pdp11 operating systems, supported split-space -- Unix on the 44/45/70
was just about the sole example -- but when it *was* available, it got used
*A LOT*.  This is one reason why a stock V7 did not run very well on the
smaller 11s without split-space, although if you munged it hard enough you
could make it go all right.
-- 
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry henry@zoo.toronto.edu