From: "Tom Demmer" <DEMMER AT brain1 DOT lstm DOT ruhr-uni-bochum DOT de>
Organization:  Lehrstuhl Stroemungsmechanik, RUB
To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>, djgpp-workers AT delorie DOT com
Date:          Mon, 1 Dec 1997 15:17:34 GMT-1
Subject:       Re: Is C: always present?
Reply-to: Demmer AT lstm DOT ruhr-uni-bochum DOT de
Message-ID: <A88018A430C@brain1.lstm.ruhr-uni-bochum.de>
Precedence: bulk

> Sometimes, there's a need to depend on a certain disk to always be 
> present.  An example would be those features that need a disk access, but 
> affect some global variables, like the LFN support in the library.
> 
> The question is: can we assume that C: is such a drive?  What about 
> diskless networked machines--do they have C:?  If they do, where is that 
> disk mapped to?
> 
On NOVELL networks, it is not necessarily present. Diskless clients 
have during boot-up phase a fake A: drive (if the boot over the 
network), otherwise they mereley need their floppy. And, this is not 
uncommon here when installing a PC. A floppy with command.com, fdisk, 
format and network drivers to bootstrap the machine. No accessible 
disk required. First network drive is F: by default, here H: to have 
room for other local drives. DOS is installed via net after fdisk & 
format. 
Mapping networked drives is completely free to your will. Usual is to 
have Z: Y: X: and downwards as search drives, but not mandatory.

One idea that comes to mind is to check COMSPEC, because this must be
mapped to a drive and includes the drive letter. Yes, it is risky, I 
remember faintly people having trouble with DJGPP and no COMSPEC set. 
What you cannot rely upon is that you have write access anywhere 
along the path to whatever COMSPEC points to. 
Another is to stat drive:\NUL and see if it exists. But I'm not sure 
this works already in the phase you require it. 

Hope this helps, though I doubt that ;-)

Ciao
Tom

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