Reserved directory & file names

You cannot create a directory or file called \PIPE. This is a necessary 
restriction, because the names of named pipes all begin with \PIPE\ (and 
pipes are handled like ordinary files in OS/2). 

Also you cannot create or access directories or files with the names of 
loaded device driver in any directory. Some standard device driver for 
OS/2 are the following (there may be others not listed here):   

+---------------+---------------+
|Device name    |Device driver  |
+---------------+---------------+
|APM$           |               |
+---------------+---------------+
|CLOCK$         |CLOCK01.SYS    |
+---------------+---------------+
|COM1 - COM4    |COM.SYS        |
+---------------+---------------+
|CON            |               |
+---------------+---------------+
|DOS$           |DOS.SYS        |
+---------------+---------------+
|IBMKBD$        |IBMKBD.SYS     |
+---------------+---------------+
|KBD$           |IBMKBD.SYS     |
+---------------+---------------+
|LOG$           |LOG.SYS        |
+---------------+---------------+
|NUL            |(NUL device)   |
+---------------+---------------+
|LPT1 - LPT9    |PRINT01.SYS    |
+---------------+---------------+
|MOUSE$         |MOUSE.SYS      |
+---------------+---------------+
|OEMHLP$        |SCREEN01.SYS   |
+---------------+---------------+
|PCLOGIC$       |PCLOGIC.SYS    |
+---------------+---------------+
|POINTER$       |POINTDD.SYS    |
+---------------+---------------+
|PRN            |PRINT01.SYS    |
+---------------+---------------+
|RESERVE$       |RESERVE.SYS    |
+---------------+---------------+
|RESMGR$        |TESTCFG.SYS    |
+---------------+---------------+
|SCREEN$        |SCREEN01.SYS   |
+---------------+---------------+
|TIMER$         |CLOCK01.SYS    |
+---------------+---------------+
|SINGELQ$       |PMDD.SYS       |
+---------------+---------------+

In general you should not use a file or directory name ending with a 
dollar sign. 

Warning 

You can create a directory or file with the name of a device if the 
necessary device driver for the device is not loaded. But be aware, that 
you cannot access that file or directory anymore after installing the 
device driver again! 

(see also Output & Input control, Reserved names for files in REXX, Check 
if a name describes a device or a file and Using the CLOCK$ device.) 

If you really need to create or delete a directory with the name of a 
device you can use the following trick: 

 

   REM *** Create a directory called APM$ in the current directory
   md APM$\.

   REM *** Delete a directory called APM$ in the current directory
   rd APM$\.

   REM *** Create a directory called CLOCK$ in the root directory
   md \CLOCK$\.

   REM *** Delete a directory called CLOCK$ in the root directory
   rd \CLOCK$\.