Undocumented DOS Calls

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Article #7875

#7875

From: John Allen
Date: Thu, 11 Sep 1986 22:01

27 lines
1651 bytes

Does anyone out there have any documentation for any of the
undocumented DOS calls?  For example: DOS interrupt (21H),
function 37H for switch characters and device name resolution.

I'm interested in any of those little gems which are listed
as "USED INTERNALLY BY DOS" in the "Technical Reference".
I know that one of the periodicals (PC Magazine?) printed
an article which outlined one of these during the last few
months, but I can't locate the issue.

I am particularly interested in the call(s) which return
disk volume information for both floppies and hard disks.
(One side vs. two sides, location of FAT, location of root,
etc.)

Any information, either through mail or the net would be
greatly appreciated.

Thanks,

============================================================================
John Allen
NetExpress Communications, Inc.		seismo!{sundc|hadron}!netxcom!jallen
1953 Gallows Road, Suite 300		(703) 749-2238
Vienna, Va., 22180
============================================================================

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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!sundc!hadron!netxcom!jallen
From: jallen@netxcom.UUCP (John Allen)
Newsgroups: net.micro.pc
Subject: Undocumented DOS Calls
Message-ID: <70@netxcom.UUCP>
Date: Thu, 11-Sep-86 18:01:50 EDT
Article-I.D.: netxcom.70
Posted: Thu Sep 11 18:01:50 1986
Date-Received: Thu, 11-Sep-86 22:42:23 EDT
Reply-To: jallen@netxcom.UUCP (John Allen)
Distribution: na
Organization: NetExpress Communications Inc. Vienna, Va.
Lines: 27
Keywords: DOS calls int21
Summary: Want information re: undocumented DOS functions