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From: dan@rna.UUCP
Newsgroups: net.unix-wizards
Subject: V6 co-routine scheme and multitasking ?
Message-ID: <225@rna.UUCP>
Date: Thu, 15-Mar-84 01:03:15 EST
Article-I.D.: rna.225
Posted: Thu Mar 15 01:03:15 1984
Date-Received: Fri, 16-Mar-84 00:37:13 EST
Lines: 21

Hi,
	Remember the V6 co-routine scheme ? It was a package of C functions
such as crfork(), crread() and crwrite() which implemented behavior
"in many respects like a set of processes working in the same address space".
	Has anyone ever played with those routines ? (They disappeared in PWB
and V7). Does anyone have the V6 source code lying around (I suspect at least
some of the functions were PDP-11 assembler) ?
	I am interested in similar facilities for multitasking real-time
applications. Using the USG 5.0 shared memory calls would probably have similar
effect but may not be suitable for real-time, possibly standalone situations.
	I envision a set of routines (as portable as possible amongst different
CPU's) which implement an environment for a set of processes in the same
(at least data) address space. I know I can probably go with those ROM based
mini-kernels like Hunter and Ready's VRTX or JMI's C executive.
	Has anyone worked out similar schemes - preferably with hooks to use
multiple CPU's on the same memory bus and multitasking within each and among
all the CPU's.

					Cheers,
					Dan Ts'o
					...cmcl2!rna!dan