Path: utzoo!utgpu!water!watmath!clyde!rutgers!husc6!m2c!ulowell!page
From: page@swan.ulowell.edu (Bob Page)
Newsgroups: comp.sys.amiga
Subject: Re: RAW Track READ and Write
Keywords: Track, TrackDevice, Disk, Floppy
Message-ID: <2507@swan.ulowell.edu>
Date: 25 Jan 88 16:14:57 GMT
References: <114@dover.uucp>
Reply-To: page@swan.ulowell.edu (Bob Page)
Organization: University of Lowell, Computer Science Dept.
Lines: 31

fullmer@dover.uucp (Glen Fullmer) wrote:
>copy from one disk to another.  The second disk always becomes corrupted, 
>it still lists the old directory afterward but when the disk is removed and 
>reinserted the "NOT A DOS DISK" requestor appears.

You can use 'diskchange df1:' rather than removing/inserting the disk.

DOS wants a floppy to look like:

block   0: First longword is 0x444F5300 (in ascii, that's "DOS<NULL>")
block 880 (decimal):  Must be a valid ROOT block.  See AmigaDOS
	Techinal Ref Man (TRM) for details.
block 881 (decimal): Must be a valid BITMAP block.
	Doesn't really matter what this looks like, as long
	as the checksum (first longword, calculated just like the root
	block) is correct.  Of course you'll have to make it correct
	if you actually want to USE the disk.

During disk validation, all the blocks referenced in the root block
(the top-level directories) are accessed, so make sure they're OK too.

You can get more info on bitmaps and root blocks from the article
"Notes on 1.2 Amiga Trackdisk Format" by Carolyn Scheppner and Andy
Finkel, which appeared in the Nov/Dec '87 issue of AmigaMail.  I'd
post parts of it here, but I don't know if CBM would squeal about
copyrights, etc (although there are none listed).

..Bob
-- 
Bob Page, U of Lowell CS Dept.  page@swan.ulowell.edu  ulowell!page
"I don't know such stuff.  I just do eyes."  -- from 'Blade Runner'