Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!pprg.unm.edu!hc!ames!amdcad!sun!pitstop!sundc!seismo!uunet!munnari!otc!metro!ditsyda!mqcomp!jamespw
From: jamespw@mqcomp.oz (Warlow)
Newsgroups: comp.unix.wizards
Subject: Re: ISBN
Message-ID: <634@mqcomp.oz>
Date: 3 Feb 89 05:51:43 GMT
References: <18244@adm.BRL.MIL> <884@amethyst.ma.arizona.edu>
Reply-To: jamespw@mqcomp.mq.oz (James Picton-Warlow)
Organization: Computing Discipline, Macquarie University
Lines: 7

In article <884@amethyst.ma.arizona.edu> rsm@amethyst.ma.arizona.edu (Robert Maier) writes:
 [ ISBN's are in the form ...]
>with a weighted mod 11 checksum.  (The mysterious "X" in the checksum
>field, which one occasionally encounters, means 11.)

I've seen this twice. Surely not. In arithmetic mod 11 one needs a new
symbol for 10, not 11. Which is what the X is for.
D