By default, DEC DATATRIEVE uses EDT when you issue the EDIT
       command. You can specify DEC TPU, LSE, or EDT by assigning the
       logical name DTR$EDIT. There are two ways to assign DTR$EDIT
       to the acronym TPU, LSE, or EDT. Note that you must specify the
       three-character acronym, such as TPU, not DEC TPU.

       o  Use the DCL DEFINE command. For example:

          $ DEFINE DTR$EDIT TPU

       o  Use the DEC DATATRIEVE function FN$CREATE_LOG from within DEC
          DATATRIEVE. For example:

          DTR> FN$CREATE_LOG ("DTR$EDIT", "LSE")

       The assignment from within DEC DATATRIEVE lasts for that DEC
       DATATRIEVE session. To make the assignment permanent, use the
       DEFINE command in your login file.

       To use LSE with callable DEC DATATRIEVE, add the module
       name LSE to your DEC DATATRIEVE options file. For example:
       SYS$SHARE:DTRSHRxx/SHARE, - DTR$LIBRARY:TERMSERVE/LIBRARY
       /INCLUDE=(ADT,EDT,GUI,HLP,LSE,TPU)

       This options file enables calling programs to use ADT, the EDT
       editor, Guide Mode, DEC DATATRIEVE online help, LSE, and DEC TPU.

       See the documentation for LSE for more information about that
       product. See the help topic DEC TPU for more information about
       using DEC TPU with DEC DATATRIEVE.