Path: utzoo!attcan!sobmips!roe
From: roe@sobmips.UUCP (r.peterson)
Newsgroups: comp.unix.wizards
Subject: Re: Backup verification
Message-ID: <1990Feb3.163616.12766@sobmips.UUCP>
Date: 3 Feb 90 16:36:16 GMT
References: <737@visdc.UUCP>
Organization: Sobeco Group - Montreal, Canada
Lines: 17

From article <737@visdc.UUCP>, by jiii@visdc.UUCP (John E Van Deusen III):
> The real performance problems come from the the pipes, IPC.  It was
> bad form for me not to remove all that I could, (although I seem to
> count just as many pipelines in the second version).  In particular
> dd if=/dev/ct bs=5120 | sum will never beat sum < /dev/ct.

Probably not - if sum were smart enough to do block reads at the correct
blocksize.  Its' not.

In fact, several tape device drivers that I've used forbid reads smaller
than a block - as an attempt to reduce possible noise conditions, I
believe.  BSD43 unix is a perfect example of this.

-- 
One makes strong assumptions delving	       Roe Peterson
into the beginning of the universe...	       {uunet,mcgill-vision}!sobeco!roe
	- Stephen Hawking, Cambridge