Q67147: BASIC Files Limited to 32 MB Without DOS 4.00/4.01 Patch

Article: Q67147
Product(s): See article
Version(s): 2.00 2.01 3.00 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S901107-113 B_BASICCOM | mspl13_basic
Last Modified: 5-DEC-1990

QuickBASIC or other programs that use file I/O (Input/Output) may give
incorrect results when accessing files larger than 32 megabytes (MB)
under MS-DOS versions 4.00 and 4.01. (MS-DOS 4.00 and later introduce
the capability for file sizes larger than 32 MB.) This is a problem
with MS-DOS 4.00 and 4.01, and can be corrected with a program called
PATCH32M available in the Software/Data Library and as an application
note from Microsoft.

This information applies to Microsoft QuickBASIC versions 2.00, 2.01,
3.00, 4.00, 4.00b, and 4.50; to Microsoft BASIC Compiler versions 6.00
and 6.00b for MS-DOS; and to Microsoft BASIC Professional Development
System (PDS) versions 7.00 and 7.10 for MS-DOS.

Under DOS 4.00 and 4.01, when you append to files larger than 32
megabytes in length, BASIC's LOF function returns incorrect values for
the file length. Specifically, if you write to a random-access file,
and the size moves past the 33,554,432 byte (32 MB) boundary, the file
size given by MS-DOS's DIR command and BASIC's LOF function may remain
at the last even record boundary below 33,554,432 bytes. However, the
file will be written properly, and a CHKDSK /F followed by a DIR will
return the correct size.

This is a problem in MS-DOS versions 4.00 and 4.01, and can be
corrected by running the patch program PATCH32M.EXE available in the
Software/Data Library. For information on how to obtain PATCH32M.EXE,
search in the Software/Data Library for the word PATCH32M.

Additional information may be found by querying in the Microsoft
Knowledge Base on the following words:

   DOS and 4.01 and 32 and MB

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.