Disabling drive letter B: on one-floppy drive machines

Disabling drive letter B: on one-floppy drive machines

Post by Allen Yu » Wed, 28 Jul 1993 09:15:28



On one-floppy drive machines, the drive letters A: and B: refers to the
same physical drive.  DOS asks you to switch floppies when needed.

Is there any way to disable this behavior?  I want to make B: somehow
unusable, so that when something refers to "B:" I'll get an error
message of some sort.

I'm using IBM DOS 5.00 Rev. 1, but I'd like to hear answers for any version
of DOS.

Thanks in advance.

--- Allen Yuen

--




 
 
 

Disabling drive letter B: on one-floppy drive machines

Post by Stan Bro » Wed, 28 Jul 1993 22:32:57



>On one-floppy drive machines, the drive letters A: and B: refers to the
>same physical drive.  DOS asks you to switch floppies when needed.

>Is there any way to disable this behavior?  I want to make B: somehow
>unusable, so that when something refers to "B:" I'll get an error
>message of some sort.

Do you _really_ want an error message, or do you just want to disable
the prompt to change diskettes?  If disabling the change prompt is all
you care about, use this command in your AUTOEXEC.BAT file:

        assign b=a

This is explained fully in question 404 of the FAQ list.

However, if you specifically want an error message for refrerring to b:,
I'm not sure how to do that.

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Disabling drive letter B: on one-floppy drive machines

Post by Allen Yu » Thu, 29 Jul 1993 06:47:59



>Do you _really_ want an error message, or do you just want to disable
>the prompt to change diskettes?  If disabling the change prompt is all
>you care about, use this command in your AUTOEXEC.BAT file:

>        assign b=a

Yes, I really want an error message.  I want it to behave the way like when
there is no hard drive D: and I try to use D:

More answers welcome.  Thanks.

--- Allen Yuen

--




 
 
 

Disabling drive letter B: on one-floppy drive machines

Post by Christopher Linds » Thu, 29 Jul 1993 15:36:53



>Yes, I really want an error message.  I want it to behave the way like when
>there is no hard drive D: and I try to use D:

        I ran into the same problem once before, and I couldn't figure out
how to solve it.  So, with every disk access routine, it installs the critical
error handler and checks the BIOS memory at 40:10 (same as INT 11h)...  The
leftmost 2 bits (7, 6) represent the number of disk drives on a system...  It
will return only a 1 if only drive A:, 2 if A:-B:, etc...  If they wanted
drive B:, it will compare this with the number of floppies and return an error
if necessary...

        You've probably already thought of this, but, here it is just in case.

Chris

 
 
 

Disabling drive letter B: on one-floppy drive machines

Post by Sezgey Pachkovs » Thu, 29 Jul 1993 16:30:46




: >Yes, I really want an error message.  I want it to behave the way like when
: >there is no hard drive D: and I try to use D:

:       I ran into the same problem once before, and I couldn't figure out
: how to solve it.  So, with every disk access routine, it installs the critical
: error handler and checks the BIOS memory at 40:10 (same as INT 11h)...  The
: leftmost 2 bits (7, 6) represent the number of disk drives on a system...  It
: will return only a 1 if only drive A:, 2 if A:-B:, etc...  If they wanted
: drive B:, it will compare this with the number of floppies and return an error
: if necessary...

Well, that's a bit too complicated solution, I am afraid. All you need to do
is to clear a valid flag in drive B's CDR. The 10-liner to do the trick was
supplied as an example to "Undocumented DOS" (sorry, I do not have a complete
reference to it at hand). And, if you don't mind to mess with your DOS insides
for half a hour to make your own program, Ralf Brown's interrupt list will give
you all the necessary information on accessing CDR...

Cheese,

/Serge.P

--

Russian guy from the Zurich university...

 
 
 

Disabling drive letter B: on one-floppy drive machines

Post by Erwin Dondo » Thu, 29 Jul 1993 18:12:31



|> >On one-floppy drive machines, the drive letters A: and B: refers to the
|> >same physical drive.  DOS asks you to switch floppies when needed.
|> >
|> >Is there any way to disable this behavior?  I want to make B: somehow
|> >unusable, so that when something refers to "B:" I'll get an error
|> >message of some sort.
|> Do you _really_ want an error message, or do you just want to disable
|> the prompt to change diskettes?  If disabling the change prompt is all
|> you care about, use this command in your AUTOEXEC.BAT file:
|>         assign b=a
|> This is explained fully in question 404 of the FAQ list.
|> However, if you specifically want an error message for refrerring to b:,
|> I'm not sure how to do that.

How about:
        assign b=z

Erwin
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Disabling drive letter B: on one-floppy drive machines

Post by Timo Sal » Fri, 30 Jul 1993 03:57:51


An extract from
 94228 May 8 11:01 garbo.uwasa.fi:/pc/ts/tsbat43.zip
 tsbat43.zip  A collection of useful batch files and tricks.

26. A simple trick to "disable" a drive
=======================================

It you wish temporarily disable a drive use the subst command for
example as follows

  md c:\none
  subst d: c:\none
To enable it again use

  subst d: /d
  rd c:\none

   All the best, Timo

..................................................................
Prof. Timo Salmi      Co-moderator of comp.archives.msdos.announce
Moderating  at  garbo.uwasa.fi anonymous FTP archives 128.214.87.1
Faculty of Accounting & Industrial Management; University of Vaasa

 
 
 

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