From:	Andrew Crabtree <andrewc AT typhoon DOT rose DOT hp DOT com>
Message-Id:	<199711030153.AA093761986@typhoon.rose.hp.com>
Subject:	Re: Incompatibilities with NT
To:	eliz AT is DOT elta DOT co DOT il (Eli Zaretskii)
Date:	Sun, 02 Nov 1997 17:53:05 PST
Cc:	djgpp AT delorie DOT com
In-Reply-To:	<Pine.SUN.3.91.971102150225.11098i-100000@is>; from "Eli Zaretskii" at Nov 2, 97 3:02 pm
Reply-To:	andrewc AT rosemail DOT rose DOT hp DOT com

 
> > Clearcase makes a special drive letter that you access you version
> Does the DOS box know about it?  That is, can you chdir there, list
> files with DIR, copy files with XCOPY, etc., all using the default NT
> shell (cmd.exe, I think)?
As far as I can tell yes.  The NT Default command interpreter 
can get to it, and 'cd' and 'dir' both work.
 
> You need to establish whether the way Clearcase creates that drive
> makes it visible to DOS programs.  If the tests above from the DOS box
> work, please type the following (in the DOS box):
> 
>        truename m:\
> 
> and tell what does it print.  (I assume that this command still works
> in NT's native shell, but I cannot test this, as I have no access to
> NT.)
I will test it on Monday, as I only have access to my unix machine
from home since Microsoft doesn't provide and rlogin capability, and
I don't own one of the addon remote control packages.
 
> Also, it is not clear to me why do they make a drive letter at all?
> The files are kept locally on your hard drive, right?  So why cannot
> you just access them using whatever pathname they are installed in?
I've tried to explain clearcase to people before and done a lousy
job of it.  Basically, it is nothing like rcs/cvs or sccs.  It uses two
types of databases, vobs and views.  Vobs are where the real (checked-in)
files go.  Each user has their own view for private storage.
  Anyway, the vobs and views 
reside on a server and are accessed by the client via rpcs (i think).
The trick is, that clearcase patches the kernel (unix here), and 
makes the paths to the files the same for everyone.  It does a bunch of 
other neat stuff as well, like store dependencies for every derived object
it creates, so that its own make will know when to update things 
(useful when header files change, or makefiles, or the compiler itself),
it also allows users to share derived objects.  If it detects 
that all dependencies are the same between you and someone else, it 
will symlink .o files in.  It has tons of other stuff for triggers
and policies and distributing computing.  Whoops - this is getting long
winded.  They just recently ported to NT, and I'm just now playing
with NT->Unix compatibility they offer.

Andrew

--
_______       ___________________________________________________________
           /                       	                  Andrew Crabtree 
          /                          	      Workgroup Networks Division 
         ____       ___  /                                Hewlett-Packard 
        /     /    /    /   		                    Roseville, CA 
     __/   __/    _____/                                     916/785-1675
                 /                           andrewc AT rosemail DOT rose DOT hp DOT com
___________   __/   _____________________________________________________

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