KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q105274: Solving the "Insufficient Memory to Run" Situation

Article: Q105274
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 06-NOV-1999

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

- Microsoft Windows Software Development Kit (SDK) 3.1 
-------------------------------------------------------------------------------

SUMMARY
=======

Each task under Windows requires a data structure allocated below 1 megabyte
(MB) called the Task Data Base (TDB). Under the debug version of Windows,
failure of a TDB's allocation shows up as:

  t Kernel: GlobalAlloc(200) failed for ????

This error occurs within the context of LoadModule as it attempts to start a new
task under a low conventional memory condition.

The most common cause of low conventional memory is fixed allocations made on
behalf of a dynamic-link library (DLL). Fixed allocations should be used only
for code and data touched at interrupt time. All other allocations should be
made with the moveable attribute.

MORE INFORMATION
================

The Windows heap consists of all conventional and XMS memory available after
WIN.COM and WIN386.EXE/DOSX.EXE are loaded by MS-DOS. These two physically
separate blocks are combined into a single linear address space to make up the
global heap.

Windows allocates fixed objects with a bottom up/first fit algorithm. As more
fixed objects are allocated from the heap, conventional memory gets pinched.
Eventually, even a small allocation for the TDB fails resulting in LoadModule
returning 0 (zero).

The HEAPWALK.EXE utility provides a view onto the global heap to determine what
is using up conventional memory. The Sort Address menu item sorts the main heap
with lower addresses at the top of the list. Any object with an address of 9FFFF
or below is in conventional memory. An object with an "F" set in the FLG column
is fixed. Any fixed object owned by an application or its dependent dynamic-link
libraries that is not a TDB (TYPE Task in HEAPWALK) should be considered
suspect.

The module definition (.DEF) file should mark CODE MOVEABLE DISCARDABLE and DATA
MOVEABLE. Any allocations should contain the GMEM_MOVEABLE attribute. The
EXEHDR.EXE utility can be used to indentify modules that use the fixed attribute
for their code or data segments. Segments without the <moveable> attribute
in the "flags" column of EXEHDR's output are fixed.

Additional query words: no32bit 3.10

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1

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

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.