Path: utzoo!mnetor!uunet!dalcs!lane
From: lane@dalcs.UUCP (John Wright/Dr. Pat Lane)
Newsgroups: comp.sys.ibm.pc
Subject: Tricks with JOIN and SUBST (was Re: Using large hard disk w/MS-DOS)
Message-ID: <2786@dalcs.UUCP>
Date: 20 Feb 88 12:22:29 GMT
References: <3093@cup.portal.com> <3948@ihlpl.ATT.COM>
Reply-To: lane@dalcs.UUCP (John Wright/Dr. Pat Lane)
Organization: Math, Stats & CS, Dalhousie University, Halifax, NS, Canada
Lines: 53

In article <3948@ihlpl.ATT.COM> figlik@ihlpl.UUCP (55242-Figlik,J.R.) writes:
>In article <3093@cup.portal.com> truett@cup.portal.com writes:
>>With regard to DOS being able to handle multiple partitions on a hard disk:
>>...
>
>The MS-DOS "JOIN" command can take a disk and make it look as if it's a 
>directory on another disk. ....
>

This is a favorite trick of mine.  Also, on systems which have only one
hard disk partition, I use the DOS "SUBST" command to take a directory and
make it look like another disk.  ie.

			subst d: c:\work

creates a fake drive D: whose root directory is the "work" subdirectory of C:.
This directory is still acessable as "c:\work".  Note that the subdirectory
can be several levels down from the root and that the same subdirectory can
be simultaneously SUBST'd to more than one drive.  The subdirectory cannot,
however, be on a SUBST'd drive (use it's pathname on the real drive).

Advantages:  
	Easy to implement and un-implement (no Fdisking and re-formatting).
	"Partition" sizes arn't fixed since it's all the same disk.

Disadvantages:
	Doesn't break 32-Meg barrier and doesn't allow non-standard sector
	and cluster sizes as do the "disk enhancer" pgms.
	Doesn't provide protection against re-formatting or munging the FAT 
	in one partition (with real partitions you'd at least have your other
	partitions intact).  Ditto having a place to store stuff while you 
	re-format a partition.
	Doesn't provide performance advantage of having fewer seeks (with two
	physical drives?) and minimizing file fragmentation.
	Some programs get confused.  Norton's Utilities don't like SUBST'd 
	drives including one's that shouldn't care, like "dirsort".  As noted,
	even SUBST won't work on a subdirectory of a SUBST'd drive.
	There seems to be a bug in CHKDSK (IBM PC-DOS 3.20) where the "/f"
	parameter is ignorred if there is a SUBST'd directory on the drive. 
	If you define a ram-disk or otherwise install a device driver in
	CONFIG.SYS that uses up a drive letter, you will have to use a
	different letter for your SUBST'd drive which is annoying.

I'd like to hear from anyone with comments about the last three disadvantages.

Regards,
John Wright

-- 
John Wright      //////////////////      Phone:  902-424-3805  or  902-424-6527
Post: c/o Dr Pat Lane, Biology Dept, Dalhousie U, Halifax N.S., CANADA  B3H-4H8 
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