A BRIEF DESCRIPTION OF MAKETAPE.COM, LIST.COM AND COPYTAPE.COM




          MAKETAPE.COM,  COPYTAPE.COM  and  the  LIST.COM  subroutine   are
     intended to be simple and foolproof ways of making a VAX DECUS tape or
     copying a DECUS tape to disk.  They may also be useful for other  tape
     copying  operations  when it is desirable to reconstruct the directory
     tree structure.


     MAKETAPE and LIST

          MAKETAPE will, if desired, construct  a  data  file  (DIRLIS.DAT)
     consisting  of  the  original  directory names, the directory sizes in
     disk blocks (optional), the directory names stripped of  the  part  of
     the  name  used  to  specify the root node, the name fo the associated
     container file and, if the  directory  has  a  subdirectory  the  word
     "NODE".   LIST.COM  is  used as a recursive subroutine to traverse the
     directory tree.  The traversal  is  postorder  which  eliminates  some
     problems in reconstructing the tree.

          MAKETAPE then goes into the copying part of the procedure,  first
     putting  on  tape  this  file and the command procedures and data file
     described in  this  file.   Then  using  either  the  DIRLIS.DAT  just
     constructed  or existing DIRLIS.DAT, it copies each directory with the
     BCK  utility.   It  then  places  a  redundant  copy  of  the  command
     procedures  and  DIRLIS.DAT at the end of the tape.  Their presence on
     the tape indicates that the procedure did not bomb during the creation
     of  the  tape,  which  should  indicate that the copying operation was
     successful.


     COPYTAPE

          COPYTAPE.COM can reverse the operation  of  MAKETAPE.COM  or  can
     instead  attach  the tree(s) to a directory of your choice or can copy
     any  branch  of  the  tree.   The  various  options  are  reached   by
     appropriate responses to prompts.


     Using the size information.

          It is sometimes useful to know the size of the directories to  be
     copied  or  restored  and  provisions  are  included  for putting this
     information in DIRLIS.DAT.  However, it does take time to get the size
     of  each  directory  so if you don't have a use for the information or
     you are in a hurry it is  better  to  answer  no  the  the  prompt  in
     MAKETAPE.   As  a  rule of thumb for tape useage a 2400 foot tape will
     hold more than 25,000 blocks at 800 bpi and almost twice  as  much  at
     1600 bpi.

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     STARTING FROM SCRATCH

          Following is a sample interactive session for copying a tape:


        $MOUNT MTA0: DECUS
        $COPY MTA0:COPYTAPE.COM *
        $@COPYTAPE
        Enter the name of the tape drive being used: MTA0:
        Enter the tape label: DECUS
        Use the DIRLIS.DAT from the tape? YES
        Display the list of directories? NO (YES if you want to review the
                              the directory structure or directory sizes.)
        The directories can be copied with ather original names
        and structure or under a directory of your choice.  If
        you are copying the whole tape the original structure is
        recommended.
        Indicate ORIGINAL or NEW: ORIGINAL
        Copy all of the directories? YES
        
        IF "" .NES. "NODE" THEN $CREATE/DIR [DECUS.F79.BUILD]
        SET DEFAULT [DECUS.F79.BUILD]
        MCR RST *.*;*/FR=TAPE:10101.CON
                .
                .
                .
         *** COPYING COMPLETE ***