1 FILES
File  specifications  provide  the  system  with  the information
necessary  to identify  a unique file or device.  Normally, only the
file name, with type, needs to be used.  The fully qualified file
specification has the following format: 

     node::device:[directory]filename.type;version

The punctuation marks are  required to separate the fields of the file
specification.  These fields are: 

     node          Network node name
     device        Device name
     directory     Directory name or sequence
     filename      File name
     type          File type
     version       File version number

All the fields but filename and type have default values.
 
     Node      - Your local DECnet node name            (SHOW NETWORK)
     Device    - Your default device, usually USR$ROOTn (SHOW DEFAULT)
     Directory - Your default directory                 (SHOW DEFAULT)
     Version   - highest version
 
When a new version of a file is created, as with a text editor, the old
version remains.  Be sure to use the PURGE command, when appropriate, to
delete all but the most recent version(s) of your files. You should
rename old copies of files which you wish to keep, both for
identification, and to prevent accidental purging. 
 
You should always use logical device names, such as USR$SCRATCH or
SYS$PRINT, rather than device names such as DUK3 or LCA0.  Changes in
system configuration and future software releases are expected to
require occasional changes in the the actual hardware names assigned to
some system logical names. 

At Fermilab, your Username is used for the name of your root directory.
You may create up to eight levels of subdirectory, using the CREATE/DIR
[directory_name] command.  For example, you may wish to place items 
related to program X in a directory such as [username.X], and test 
procedures for that program in subdirectory [username.X.TEST]. 
 
Wild cards may be used in specifying most parts of the file spec. 
% matches any single character, while * matches any number of 
characters in a given field. 
 
Some programs accept default type extensions. Some of these are
     
     COM - DCL Procedure
     EXE - Executable program
     FOR - FORTRAN
     HLP - HELP source text
     HLB - HELP library
     LIS - TYPE, PRINT
     MAI - MAIL folder
     MEM - RUNOFF output
     MAR - MACRO  (VAX assembler source)
     OBJ - LINKER (output from compiler)
     OLB - LINKER (object library)
     RNO - RUNOFF input
     TLB - Text library
