Is update(8) a hack? (was: Re: 6386 shutdown: I CAN'T BELIEVE at&t was really this stupid!)

[Marshall Cline]

In article <2294 at drilex.UUCP> dricejb at drilex.UUCP (Craig Jackson drilex1) writes:
>Personally, I've always thought that update(8) was a hack, ever since I
>first saw it in Version 7.  To think that someone would write an operating
>system that couldn't even keep its on-disk data structures consistent...

Sorry, don't agree.  One of the philosophical issues upon which Un*x
is built is the separation of policy and mechanism.  The kernel takes
care of mechanism, with as little policy as possible.  (No one would
claim Un*x does a perfect at this separation, but it tries).

As applications get closer to the user, many policy decisions are made
(ex: the _kernel_ treats only two chars ['/' and '\0'] as special in a
filename, but the shell has lots of meta-chars; furthermore the
"-flag" system isn't special to the shell, but many applications
follow the getopt(3) route; etc).

Avoiding delayed-write would, in general, bring performance down
pretty badly.  Given an OS that _does_ have delayed-write, the only
question is: how often should we "sync" the system?  Personally, I
think this _policy_ decision should be left _OUT_ of the kernel.

Marshall
--
	________________________________________________________________
	Marshall P. Cline	ARPA:	cline at sun.soe.clarkson.edu
	ECE Department		UseNet:	uunet!sun.soe.clarkson.edu!cline
	Clarkson University	BitNet:	BH0W at CLUTX
	Potsdam, NY  13676	AT&T:	315-268-6591