Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: AmigaDOS Filing System Block Format
Message-ID: <13727@cbmvax.commodore.com>
Date: 9 Aug 90 19:29:15 GMT
References: <2761@mindlink.UUCP>
Reply-To: jesup@cbmvax (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 32

In article <2761@mindlink.UUCP> a275@mindlink.UUCP (Travers Naran) writes:
>1. What are the "words" refered to in the AmiDOS Tech manual? Long words or
>normal 16 bit words?

	32 bits.  BCPL (original language of AmigaDos) doesn't know about
anything but longwords (without trouble).

>2. The Checksum is confusing, the manual says "Each filing system block
>contains a checksum, where the sum (ignoring overflow) of all the words in the
>block is zero." Huh??? I thought a Checksum was the sum of all the words in the
>block (not including the  Checksum) ignoring overflow? Or does that sentence
>mean that when I add up all the words in the block including the Checksum, I
>should get zero ingoring overflow?

	The checksum is the value such that adding up the entire sector gives
a result of 0.  Normally calculated by adding up the sector with checksum as
0, then taking the result and negating it for the checksum.

>3. T.SHORT and ST.ROOT, etc. where are these constants defined?

	They aren't.  Easy to figure out with any disk utility.

>4. How do I get a subscription to AmigaMail? I live in Canada and the RKM's
>only talk about the U.S. mailing address.

	Call or write to CATS (should be in the monthly posting that just
went by.)

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.cbm.commodore.com  BIX: rjesup  
Common phrase heard at Amiga Devcon '89: "It's in there!"