Path: utzoo!mnetor!uunet!husc6!bu-cs!spike
From: spike@bu-cs.BU.EDU (Spike)
Newsgroups: comp.sys.apple
Subject: Re: DOS 3.3 File Manager
Message-ID: <18472@bu-cs.BU.EDU>
Date: 9 Jan 88 22:47:21 GMT
References: <1568@mind.UUCP>
Reply-To: spike@bu-it.bu.edu (Joe Ilacqua)
Followup-To: comp.sys.apple
Organization: Boston University Distributed Systems Group
Lines: 89

In article <1568@mind.UUCP> romero@mind.UUCP (Antonio Romero) writes:
>I'm developing some software for the Apple IIe/c using Manx's C compiler
>v1.05.  I'm in a bit of a bind at the moment, because Manx's creat() 
>function from their library is rather buggy.  I can't seem to get it to
>work for creating text files-- the machine almost invariably crashes.
>Since the creat() function is evidently nothing but an interface to the file
>manager of DOS 3.3, I'd like to try bypassing the library altogether 
>and calling the file manager directly, but I can't find a description of
>the file manager anywhere in the technical reference manual for DOS 3.3 or
>in the Dos Programmer's Toolkit.   Does anyone out there know a readily
>available reference which describes the use of the file manager? 

	This is cribbed from _Beneath_Apple_Dos_ [Worth, Lechner] get
it if you can!!

	O.K. to use the File Manager you do to things

First:
	You tell the File Manager the location of your parameter list.
This is done with a  'JSR $3DC'  where the high part of the address is
in Y and the low in A.

Second:

	The file manager is call with a  'JSR $3D6'.  If a file is not
found and the X refister contains 0 then the file is created; if X
does not contain 0 an error is returned.

For the Open call the parameter list should look like:

Byte
00      ->  01 (OPEN)
02/03   ->  Fix record length or 0000 if variable
04	->  Volume number or 00 for any
05	->  Drive [01 or 02]
06	->  Slot  [01 thur 07]
07	->  File type
	$00 = TEXT  $01 = INTEGER BASIC  $02 = APPLESOFT BASIC $04 = BINARY 
	$08 = RELOCATABLE  $10 = S TYPE  $20 = A TYPE  $40 = B TYPE
08/09	->  Low/High address of filename  (30 chars)
0C/0D	->  Low/High address of workarea buffer  (45 bytes)
0E/0F	->  Low/High address of Track/Sector list buffer (256 bytes)
10/11	->  Low/High address of data buffer  (256 bytes)


	The three buffers are initialized by the file manager not by
the caller


The call returns

Byte

07	->  File type opened  (useful if the file was not just created)
0A	->  Return Code
	    $00 = No Error  $02 = Bad Call  $03 = Bad Sub Call 
	    $04 = Write Protected  $05 = End Of Data  $06 = File Not Found
	    $07 = Volume Mismatch  $08 = Disk I/O Error   $09 = Disk Full
	    $0A = File Locked

OPEN should alway be follow by a POSITION call.  For creat you would want to
set the position to the start of the file i.e. 02-05 = 00 00 00 00.

BYTE
00	->  0A (Position)
02/03	->  Relative record number (0000 is the first) if fixed record length
	    0000 if not fix record.
04/05   ->  Offset in to record or if not fix record offset in to file
0C/OD   ->  Low/High address of data buffer (256 bytes)

0A	->  Return code

CLOSE Cleans up and updates the catalog.  It looks like:

BYTE
00	-> 02 (Close)
0C/0D	->  Low/High address of workarea buffer  (45 bytes)
0E/0F	->  Low/High address of Track/Sector list buffer (256 bytes)
10/11	->  Low/High address of data buffer (256 bytes)

0A	->  Return code

	"Last night I had that dream again. I dreamt I had to take a
		test, in a Dairy Queen, on another planet."
 UUCP:	...!harvard!bu-cs!bu-it!spike  ARPANET: spike@bu-it.bu.edu
   CSNET: spike%bu-it@bu-cs   BITNET: engemnc@bostonu "VPS sucks"

-- 
->Spike