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
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