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Article View: comp.sys.amiga.tech
Article #4828

Re: AmigaDOS Filing System Block Format

#4828
From: Dallas J. Hodgson
Date: Sat, 11 Aug 1990 00:00
41 lines
2715 bytes
In article <2761@mindlink.UUCP> a275@mindlink.UUCP (Travers Naran) writes:

<various items deleted>

>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?

Somewhat common trick I've seen in other places: reset the word where the
checksum is stored to 0. Checksum the entire block. NEG the checksum, and
place it in it's proper position in the block. Later you can checksum the
whole thing, checksum 'n all - and will it come out 0.

>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.

So, is Canada so far away? Write CATS-Info in WestChester,PA and sign up for
the Certified Developer program. Well worth the $50 (US).

>--
>-------------------------------------------------------------------
>Travers "T'aran" Naran (I am male)
>Simon Fraser University, Computing Science (Burnaby, B.C., Canada)
>New Westminster, British Columbia, Canada, North America, etc...
>Whovian, Prober, Treker, Quantum Leaper....
>Mailing addresses:
>   Usenet  Travers_Naran@mindlink.UUCP
>or      uunet!van-bc!rsoft!mindlink!Travers_Naran
>------------------------------------------------------------------

+----------------------------------------------------------------------------+
| Dallas J. Hodgson               |     "This here's the wattle,             |
| Metaphor Computer Systems       |      It's the emblem of our land.        |
| Mountain View, Ca.              |      You can put it in a bottle,         |
| USENET : djh@metaphor.com       |      You can hold it in your hand."      |
+============================================================================+
| "The views I express are my own, and not necessarily those of my employer" |
+----------------------------------------------------------------------------+
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!metaphor!neuromancer!djh
References: <2761@mindlink.UUCP>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!metaphor!neuromancer!djh
From: djh@neuromancer.metaphor.com (Dallas J. Hodgson)
Newsgroups: comp.sys.amiga.tech
Subject: Re: AmigaDOS Filing System Block Format
Message-ID: <1368@metaphor.Metaphor.COM>
Date: 11 Aug 90 00:00:57 GMT
References: <2761@mindlink.UUCP>
Sender: news@metaphor.Metaphor.COM
Reply-To: djh@neuromancer.metaphor.com (Dallas J. Hodgson)
Organization: Metaphor Computer Systems, Mountain View, CA
Lines: 41