Q128550: Memory Leak: MS-DOS-Based Apps Starting Non-MS-DOS-Based Apps

Article: Q128550
Product(s): Microsoft Windows NT
Version(s): 3.5
Operating System(s): 
Keyword(s): 
Last Modified: 01-FEB-2002

WINDOWS

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Windows NT Workstation version 3.5 
- Microsoft Windows NT Server version 3.5 
-------------------------------------------------------------------------------

SYMPTOMS
========

MS-DOS-based applications that start Windows-based, POSIX, or OS/2-based
applications under Windows NT may experience memory leaks.

CAUSE
=====

Two different memory leaks can occur. One memory leak occurs when the MS-
DOS-based application does not close a Process Object handle properly.

To observe the memory leak:

1. Run Performance Monitor.

2. From the Edit menu, choose Add to Chart.

3. From the Object list box, select Objects.

4. From the Counter list box, select Processes.

5. Choose Add and then choose Done.

A leakage of this resource will result in the gradual depletion of non- paged
pool (a vital Windows NT resource).


The other memory leak occurs when an MS-DOS-based application continuously starts
non-MS-DOS-based applications, creating a looping situation. This results in the
loss of Private Bytes associated with NTVDM.EXE running the MS-DOS-based
application.

To observe the memory leak:

1. Run Performance Monitor.

2. From the Edit menu, choose Add to Chart.

3. From the Object list box, select Process.

4. From the Instances list box, select NTVDM.

5. From the Counter list box, select Private Bytes.

6. Choose Add and then choose Done.

It may be difficult to log if there are multiple instances of NTVDM running, as
Performance Monitor will not let you distinguish between these instances if they
share the same executable name. (The Windows NT Resource Kit describes methods
to overcome this situation.) A leakage of this resource results in the gradual
consumption of Private Bytes for the NTVDM.EXE process. Private bytes
consumption is general backed by paging file so a leak of Private Bytes will
slowly consume the pagefile (a vital Windows NT resource).


STATUS
======

Microsoft has confirmed this to be a problem in Windows NT version 3.5. This
problem has been corrected in the latest U.S. Service Pack for Windows NT
version 3.5. For information on obtaining the Service Pack, query on the
following word in the Microsoft Knowledge Base (without the spaces):

  S E R V P A C K


Additional query words: prodnt 3.50 handles batchfile page file

======================================================================
Keywords          :  
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNT350search kbWinNTW350 kbWinNTW350search kbWinNTSsearch kbWinNTS350 kbWinNTS350search
Version           : :3.5

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.