Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!cs.utexas.edu!sun-barr!newstop!sun!imagen!qmsseq!pipkins
From: pipkins@qmsseq.imagen.com (Jeff Pipkins)
Newsgroups: comp.sys.ibm.pc
Subject: Re: SEGMENT:OFFSET Madness
Message-ID: <84@qmsseq.imagen.com>
Date: 12 Jan 90 17:27:26 GMT
References: <25821@cup.portal.com>
Reply-To: pipkins@qmsseq.UUCP (Jeff Pipkins)
Organization: QMS Inc., Mobile, Alabama
Lines: 16

What you are saying is true, for the 8086.  I suppose a better connotation
would be base:displacement.  But any way you slice it, the terminology is
the least of the things they *SCREWED*UP*, imho.

With the advent of protected mode on the '286 and V86 mode on the '386,
the value in the segment register really is a segment number, but a segment
is no longer (necessarily) 64k bytes.  It is a segment selector.  This also
presents real problems (no pun intended).

On the 8086, before there was an 80286, it was perfectly legitimate to 
normalize the address so that the segment was between 0 and F.  Programs
that use this technique will not run under '286 protected mode or V86
mode on the '386.  This is the main reason that the term "DOS INcompatibility
bos" was coined.

[My employer my not share my opinions.  Insert your favorite disclaimer here.]