KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q79143: Using the /HIGH and /DS LINK Options

Article: Q79143
Product(s): Microsoft Programming Utilities
Version(s): MS-DOS:2.x,3.x,4.x,5.0x,5.2,5.3x,5.5,5.6
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 30-OCT-1999

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

- Microsoft LINK for MS-DOS, versions 2.x, 3.x, 4.x, 5.0x, 5.2, 5.3x, 5.5, 5.6 
-------------------------------------------------------------------------------

SUMMARY
=======

The Microsoft LINK /HIGH option instructs the loader to place to program into
RAM at the highest possible address. However, the Program Segment Prefix (PSP)
is loaded into low memory. When the LINK command line does not include the /HIGH
option, the entire program is loaded into the lowest possible address in the
first available block of RAM.

The LINK /DS[ALLOCATE] option relocates each address in DGROUP such that the last
byte in the segment has offset FFFFh.

The /DS and /HIGH options are not recommended for use with applications developed
in a high-level language. These switches are provided for use with a real-mode
assembly-language application.

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

When the LINK command line specifies the /HIGH option, the application owns all
memory between its segments (which are loaded at the highest possible address)
and its PSP (which is loaded into low memory). Therefore, the application cannot
dynamically allocate and free memory nor can any other program be loaded into
memory.

The /HIGH switch provides room for the application stack or heap to grow downward
without colliding with any other program data, if the stack or heap is the first
segment in the memory map.

The start-up code for the Microsoft high-level language libraries is not
compatible with the /HIGH option. The libraries automatically specify the
/DOSSEG option which loads program segments into low memory. The libraries also
require dynamic memory allocation. Even though it is possible to use the /HIGH
option with custom start-up code, many of the run-time library functions that
require dynamic memory allocation would not be available.

Early versions of Microsoft FORTRAN and Microsoft Pascal generate code that must
be linked with the /DS option specified. Because the /HIGH option is often used
in conjunction with /DS, Microsoft LINK continues to support these options.

Additional query words: kbinf 2.00 2.01 2.10 2.40 2.41 2.44 2.50 3.00 3.01 3.02 3.04 3.05 3.06 3.51 3.55 3.60 3.61 3.64 3.65 3.69 4.06 4.07 4.10 5.01.20 5.01.21 5.02 5.03 5.05 5.10 5.11 5.13 5.15 5.20 5.30 5.31.009 5.50 5.60

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbZNotKeyword3 kbLINKSearch kbLINK2xDOSSearch kbLINK3xDOSSearch kbLINK4xDOSSearch kbLINK50xDOSSearch kbLINK530xDOSSearch kbLINK520DOS kbLINK550DOS kbLINK560DOS
Version           : MS-DOS:2.x,3.x,4.x,5.0x,5.2,5.3x,5.5,5.6

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

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.