From: utzoo!decvax!decwrl!qubix!msc
Newsgroups: net.unix-wizards
Title: Re: 4.1bsd mystery
Article-I.D.: qubix.214
Posted: Thu Apr 14 13:03:15 1983
Received: Mon Apr 18 06:30:57 1983
References: ucf-cs.917

	If my memory serves correctly Comet is the code name given to
	the vax 11/750 during its development at DEC.

	The comment "Comet sucks" presumably refers to the fact that
	a certain block move instruction, which was used in _doprint.s
	and hence in almost every program in 4.1bsd, worked differently
	on the 750 than the 780.  It would cause segmentation faults
	when the areas of memory involved overlapped (I think).

	This difference necessitated the re-compilation of almost
	everything in the 4.1bsd release.

	It turns out the the 750 executes the instruction exactly as
	specified in the VAX architecture manual and it is the 780 that
	is at fault.

				Mycroft Holmes