need memory syscall - (nf)

[jab at uokvax.UUCP]

#R:uiucuxc:29300011:uokvax:6100031:000:913
uokvax!jab    May  6 12:41:00 1984

On the v7 systems, there was a "research" system call called "phys()" that
allowed you to poke things into your pdp-11 segmentation registers. You
could, for example, map the I/O page into your address space and output
to the console by polling the DL11/KL11 that talks to the console terminal.
One person I know used it every once in a while as a glorified way to patch
tty structures that were wedged because of some weird dh11 code.

It's not on system {III,V}, and not in anything on a vax, because it's
terribly machine-dependent and unless you have something that looks like
old-fashioned segments, amazing things can happen. I can imagine what happens
if you try to talk to something in a Unibus space on a vax and it's not there...
(It's not polite enough to bomb your process off with a segmentation violation,
like on the 11, but instead will probably croak the kernel itself.)

	Jeff Bowles
	Lisle, IL