🚀 go-pugleaf

In article <campbell.676286703@cutmcvax> campbell@cutmcvax.cs.curtin.edu.au (Trevor George Campbell CC361) writes:
>melling@cs.psu.edu (Michael D Mellinger) writes:
>
>
>>Is there a way to avoid the "Insert disk in B drive message..." when I
>>change the A drive to B from within my MS C(6.0) program on a single
>>floppy system?  Right now it always prompts the user to insert a disk
>>into drive B and to hit RETURN even if there is already a disk in the
>>drive.
>

>I suspect NOT as DOS always thinks (and makes it look like) there are 2 floppy
>disks on a machine with only one real physical drive. I'm not sure if there
>is a way to detect if only one floppy or two are available (system config.
>byte / and interrupt (?? int 11h) spring to mind as possabilities. From memory
>there is a byte or two that tell how many drives are attached), although
>you would have to check these and then write you program to (itself) do the 
>redirecting of all requests to drive B to drive A (ie: change the filename's
>that you open)...
>

Yes there is a way to do this.  DOS keeps track of which disk is currently in
effect (i.e. which logical drive is being used A: or B:) in a location in the
BIOS area in low memory.  I don't know off hand what the location is. 

E-mail me if you'd like me to look it up, or if you have any references try
them. (Peter Norton's Programmer's Guide is good).

					Renny

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Renny Koshy						rennyk@apex.com
Apex Computer, Redmond, WA.