Date   : Wed, 15 Mar 2006 22:25:32 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: Web site: Mainly Master 512

>Message-ID: <000601c6473d$903fb830$0301a8c0@...>
 
"David Harper" <dl.harper@...> wrote:
> > Could you correct the Free Space Map info regarding the
> > checksum. Most people don't seem to get this right. It's
> > not a plain sum but a sum /with carry/, which means that
> 
> You're right. Correction made.
 
Additionally, you have to add the sector number to the checksum as
well.
 
IE, checksum for sector zero is Sum(0:255), checksum for sector
one is Sum(0:255)+1
 
That was a *really* annoying gotcha when I was getting the IDE
drive initialiser working.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
Jet Set Willy Resources - http://mdfs.net/Software/JSW