Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!rochester!pt.cs.cmu.edu!sei!sei.cmu.edu!firth
From: firth@sei.cmu.edu (Robert Firth)
Newsgroups: comp.arch
Subject: Re: 'big endian' and 'little endian' - first usage for computer
Message-ID: <8409@aw.sei.cmu.edu>
Date: 1 Feb 89 14:23:37 GMT
References: <1840@lindy.Stanford.EDU> <2951@ficc.uu.net>
Sender: netnews@sei.cmu.edu
Reply-To: firth@bd.sei.cmu.edu (Robert Firth)
Organization: Carnegie-Mellon University, SEI, Pgh, Pa
Lines: 15

In article <2951@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>[deleted discussion about using sign bit on binary data for search
> keys to distinguish them from strings in a bigendian database]
>
>You can't assume all characters in the character set are positive. EBCDIC
>and ISO latin 1 violate this assumption.

Um, I'd like to rephrase that.  The character sets you mention use
encodings between 0 and 255, which surely look positive.  Indeed,
if you ordered them by signed comparison, you'd go seriously wrong.

I think the message is that the binary representation of a character
should always be treated as unsigned; if you apply signed operations
to it, you're wrong.  Should it happen that all the characters in
the set have a leading zero, you're wrong but lucky.