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From: jonm@killer.UUCP
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Re: Redirector Wanted and Dos Tasking
Message-ID: <2256@killer.UUCP>
Date: Mon, 30-Nov-87 12:41:08 EST
Article-I.D.: killer.2256
Posted: Mon Nov 30 12:41:08 1987
Date-Received: Thu, 3-Dec-87 22:46:37 EST
References: <8711231334.aa19994@Louie.UDEL.EDU>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 44
Summary: redirector is part of MS-NET

In article <8711231334.aa19994@Louie.UDEL.EDU>, BRACKENRIDGE@C.ISI.EDU (Billy) writes:
> Does anybody have any idea how to get a redirector? or a redirector
> specification?
> 
> A redirector is part of MS-DOS (or perhaps MS-NET) that sits between
> the file system and the network. It looks at DOS file calls at the file
> handle level and calls either the disk driver or net driver as
> appropriate.
> 
> Redirectors are sold by Microsoft and Locus. Neither company acknowledges
> that they sell such a beast. As far as I can tell Locus doesn't acknowledge
> that they sell anything!
> 

The redirector from Microsoft is indeed a part of MS-NET.  It is not
as far as I know available separately, but is part of an OEM package
for licensing MS-NET.  3com, ATT, Xerox, and of course IBM PC networks
use the MS-NET Redirector as the basis for their client-side interface.

The MS-NET Redirector is tightly coupled to MS-DOS 3.1 (or later) and
handles all system calls which require remote access.  The DOS-to-redirector
interface is not publicly documented (even to OEM's).  The redirector-to-
NETBIOS interface is via software interrupt 5CH and uses a published
protocol called SMB (server message block) to interact with a server.

There are some additional MS-DOS system calls which are available
only if the redirector is installed.  The calls deal with naming and
device redirection management.  Some other system calls have additional
"modes" or options if the redirector is installed.

Third party redirectors, such as from Novell or Banyan, usually
provide these MS-DOS extensions by intercepting system call
requests.  In that case, there is no DOS-to-redirector interface
since DOS does not "see" the system call request.  The redirector-
to-network interface is usually proprietary,-- as is the client/server
protocol.  NETBIOS compatibility is a separate issue, but many non-MS-NET
network systems provide some level of compatibility.

I doubt that either Microsoft or any other network system vendor will
be interested in selling and/or publishing specifications for their
redirector unless you are prepared to license/OEM their system.


						JonM