Duplicate File Names or File Types
On a given directory or minidisk, you can give the same file name to as many files as you want, providing you assign them different file types. Or, you can create many files with the same file type, but different file names. But you cannot have files with the same file name and file type on one minidisk or in one directory. That is, you could not have two files named COST ESTIMATE on file mode A.
For the most part, file names that you choose for your files have no special significance to CMS. If, however, you choose a name that is the same as the name of a CMS command, and the file that you assign this name to is an executable module or exec procedure, then you may encounter difficulty if you try to process the CMS command whose name you duplicated.
For more information on how CMS identifies a command name, see CMS Command Search Order.
For the most part, the file type field is used merely as an identifier. Some file types, though, have special uses in CMS; these are known as reserved file types and should be avoided, if possible. For more information on reserved file types, see What Are Reserved File Types?.