  
PSS ID Number: Q97595
Article last modified on 11-20-1995
PSS database name: MSDOS
 
6.00 6.20 6.21 6.22
 
MS-DOS

Ms-DOS 6.x PATH is NOT Limited to 128 Characters
 
--------------------------------------------------------------------
The information in this article applies to:
 
 - Microsoft MS-DOS operating system versions 6.0, 6.2, 6.21, 6.22
--------------------------------------------------------------------
 
SUMMARY
=======
 
In MS-DOS 6.0 and 6.2, the 128-character limitation of the MS-DOS PATH
environment variable does not exist. To create a path with more than 128
characters, use the PATH command in the CONFIG.SYS file instead of in the
AUTOEXEC.BAT file.
 
NOTE: When setting the path in the CONFIG.SYS file, you must use a SET
command. For example:
 
   set path=c:\dos;c:\windows;
 
MORE INFORMATION
================
 
There are some restrictions on this method of using PATH. Once you set the
path in the CONFIG.SYS file, you cannot change it later. You cannot use the
%PATH% variable to append the path onto itself or run another batch file to
modify the path. If you do either of these, the path is truncated to the
first 128 characters.
 
Also, some applications do not have the ability to use a long path. For
example, the MS-DOS command SET does not display more than the first 128
characters of the path. To see the complete path, use the OS option of
Microsoft Diagnostics (MSD.EXE). If you have problems using a third-party
application and a long path, contact the manufacturer of the application
for possible solutions.
 
Paths Longer Than 256 Characters
--------------------------------
 
There is one problem with paths longer than 256 characters. If you clear
the PATH variable with the SET command as follows
 
   set path=
 
any characters beyond the 256-limit appear in your environment space,
unassociated with any environment variables. For example, if you have
a path of 260 characters, such as
 
   path=c:\dos;c:\...work
 
and you clear it with the SET command, your environment space still
contains the last four characters. If you type the SET command alone
to view your environment, you see something similar to the following:
 
   work
   PROMPT=$P$G
   COMSPEC=C:\DOS\COMMAND.COM
   TEMP=C:\TEMP
 
Microsoft has confirmed this to be a problem in MS-DOS versions 6.0, 6.2,
and 6.21. We are researching this problem and will post new information
here in the Microsoft Knowledge Base as it becomes available.
 
If the Path Is in the CONFIG.SYS File
-------------------------------------
 
If you place the path statement in the CONFIG.SYS file, you may need to
manually update the path whenever you install a new program. Many software
packages use a setup utility to install the program to the hard disk drive.
Generally, these setup utilities modify the AUTOEXEC.BAT file by adding a
directory name to the path statement. If the path statement is located in
the CONFIG.SYS file, the setup utility cannot find it and creates a new
path statement in the AUTOEXEC.BAT file. When the system is started, the
path in the AUTOEXEC.BAT file replaces the path loading from the CONFIG.SYS
file, leaving you with a path pointing to only one directory.
 
To work around this problem, each time you install a program, you must add
the program's directory name to the path in the CONFIG.SYS file and erase
the path line in the AUTOEXEC.BAT file.
 
KBCategory: kbenv kbdisplay
KBSubcategory: msdos
Additional reference words: 6.22 6.00 6.20 howto maximum length w_bob
=============================================================================
Copyright Microsoft Corporation 1995.


 
