This article was previously published under Q69563
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This article contains information on the maximum number of lines and linelength allowed for batch files (including the AUTOEXEC.BAT file) and theCONFIG.SYS file.
There is no apparent limit. A test batch file with 67,000 lines and a totalof 804,000 bytes ran all the way through (but it took 15 minutes to do soon a 386/33 machine). COMMAND.COM reads one batch line at a time, and onlyretains a file pointer for the batch file, so it does not require a largebuffer to hold batch file commands before processing them. This shouldallow for batch files that span an entire disk, if so desired.
Each batch file line does have a limit, however. Any batch file lineexceeding 127 bytes is truncated at 127 bytes before it is processed.
There is no limit on lines, but there is a 64-kilobyte (65,534 byte) limiton the overall file size. A test with a CONFIG.SYS that contained only 76-byte long REM statements (except for the last line, which loaded a devicedriver) loaded properly. There do appear to be some problems on theboundary condition when the CONFIG.SYS file size reaches 65,535 bytes.
Each CONFIG.SYS line does not appear to have a limit. The device driverINIT code is given a pointer to a read-only buffer, which contains theremainder of the CONFIG.SYS file, not just the command line. With thispointer, you can access a command line of any length.
Microsoft MS-DOS 3.1, Microsoft MS-DOS 3.2 Standard Edition, Microsoft MS-DOS 3.21 Standard Edition, Microsoft MS-DOS 3.3 Standard Edition, Microsoft MS-DOS 3.3a, Microsoft MS-DOS 4.0 Standard Edition, Microsoft MS-DOS 4.01 Standard Edition, Microsoft MS-DOS 5.0 Standard Edition, Microsoft MS-DOS 5.0a, Microsoft MS-DOS 6.0 Standard Edition, Microsoft MS-DOS 6.2 Standard Edition, Microsoft MS-DOS 6.21 Standard Edition, Microsoft MS-DOS 6.22 Standard Edition