Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!van-bc! From: lphillips@lpami.wimsey.bc.ca (Larry Phillips) Newsgroups: comp.sys.amiga.tech Subject: Re: AmigaDOS Filing System Block Format Message-ID: <1859@lpami.wimsey.bc.ca> Date: 8 Aug 90 22:40:26 GMT Lines: 51 Return-Path: To: van-bc!rnews In <2761@mindlink.UUCP>, a275@mindlink.UUCP (Travers Naran) writes: >I have some questions about this: > >1. What are the "words" refered to in the AmiDOS Tech manual? Long words or >normal 16 bit words? A word is 16 bits. A longword is 32 bits. I never noticed any discrepancy in the Amigados manual, though I suppose there could be. >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? A checksum can be whatever the author of a piece of software wants it to be. If you add up all the _LONGWORDS_ in a block, including the checksum, and ignore any overflow, the result will be zero if the checksum is correct. The checksum can be calculated by adding all the LONGWORDS in the block, not counting the checksum itself, and subtracting the calculated value from zero. >3. T.SHORT and ST.ROOT, etc. where are these constants defined? I have never seen them defined in any include files. You can find their values by using a sector editor and looking at the various block types. This will serve a dual purpose. While you are looking at those, you can see all the rest of the stuff they talk about in the Amigados manuals, and see what the FFS blocks look like too. >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. Commodore Business Machines Limited 3470 Pharmacy Avenue Agincourt, Ontario M1W 3G3 Send the request to the attention of either Alex Orgill or Paula Dawson. -larry -- Sex is better than logic, but I can't prove it. +-----------------------------------------------------------------------+ | // Larry Phillips | | \X/ lphillips@lpami.wimsey.bc.ca -or- uunet!van-bc!lpami!lphillips | | COMPUSERVE: 76703,4322 -or- 76703.4322@compuserve.com | +-----------------------------------------------------------------------+