Subj : Re: how to detect cdrom?
To   : Steve
From : CBFalconer
Date : Fri Feb 08 2002 06:07 pm

From: CBFalconer@f3.n342.z1.cereal.mv.com (CBFalconer)
Subject: Re: how to detect cdrom?

From: CBFalconer <cbfalconer@yahoo.com>

"E. S. (Steve) Fabian" wrote:
>
> CBFalconer wrote:
> >
> > Stan Brown wrote:
> > >
> > > E. S. (Steve) Fabian <ESFabian@BellAtlantic.net> wrote in
> > > comp.os.msdos.4dos:
> > > >Locating a virtual [ram] disk is not trivial.
> > >
> > > Those who have an installation of Windows 9x will find a 7 KB
> > > program
> > >         C:\WINDOWS\COMMAND\EBD\FINDRAMD.EXE
> > > that returns 3-26 in ERRORLEVEL for RAM drive as C through Z. The OP
> > > wanted a generic PC-DOS solution. I don't know whether FINDRAM will
> > > run in a 16-bit environment, but it might be worth a try.
> >
> > It should, since that directory is what W98 puts in an emergency
> > boot disk.
> >
>
> What FINDRAMD.EXE does (and the Win98 version does work under MS-DOS
> 6.22) is locate the alphabetically first drive with label "MS-RAMDRIVE",
> and returns a corresponding errorlevel. If you have a mounted partition,
> a mapped netowrk drive, or a CD-ROM with that label, FINDRAMD will find
> that. If you change the label of your virtual disk to something else
> than "MS-RAMDRIVE", it will not find it at all. If you have more than
> one, too bad.
>
> If you use a JPsoft command processor, e.g., 4DOS, (and why would you
> read this forum otherwise), you can emulate FINDRAMD.EXE with the code
> below with some enhancements:
>
> unset v
> DO dn = %@ascii[d] to %@ascii[z]
>   set d=%@char[%dn]:
>   if %@ready[%d]     EQ 0 iterate
>   if %@cdrom[%d]     NE 0 iterate
>   if %@removable[%d] NE 0 iterate
>   if %@remote[%d]    NE 0 iterate
>   switch %@label[%d]
>   case MS-RAMDRIVE .or. VIRTUALDISK
>     set v=%d
>     leave
>   endswitch
> ENDDO
> unset d dn
>
> At this point the variable v is either set to X: where X is a drive
> labeled as virtual, or it is undefined.

Sounds like you pulled it apart looking for undocumented system calls.  I'll
take your word for it.

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