 DGT IS A TASK FOR READING TAPES FROM RDOS DATA GENERAL MACHINES.
 COMMANDS ARE LIKE THOSE FOR TPC WITH THE FORMAT AS FOLLOWS.
 NOTE THAT ONE USUALLY TYPES
 R DGT
 DGT>G 0
 DGI>DV:[UIC]FILENAME.TYP;VER
   WHERE THE USUAL DEFAULTS APPLY TO FILENAMES. DGI> PROMPT
   GIVES FILE NAME TO GET DATA OFF TAPE. TAPE IS NOT
   POSITIONED PRIOR TO RUN.
   FREE FORMAT COMMANDS:
 	LETTER,NUMBER[,NUMBER]
 	WHERE
 	LETTER=R,REWIND UNIT (0 OR 1)
 	      =E, WRITE ENDFILE ON UNIT 0 OR 1
 	      =S, SKIP +- N RECORDS ON UNIT 0 OR 1
 	      =F, SKIP +- N FILES ON UNIT 0 OR 1
 	      =C, COPY PDP11 FILE TO TAPE
 	      =W, WRITE TAPE FILE TO DISK.
 	      =P, COPY PDP11 FIILE TO TAPE IN EBCDIC FOR PUNCH
 	      =I, COPY TAPE FILE TO PDP11, TAPE IN EBCDIC
 	      =G, GET DG FORMAT TAPE FILE, DUMP TO PDP11
 			(200 BIT CLEARED ON INPUT IN ALL BYTES)
 	      =O, OUTPUT TAPE WITH RECORDS TERMINATED BY C.R.
 			O UNIT,BLKFACTOR,FLAG  (FLAG=1 MEANS SET 200
 				BIT IN ALL OUTPUT CHARS, =ANYTHING ELSE
 				MEANS LEAVE 200 BIT OFF ALWAYS.
 	      =U, READ IN LIKE G EXCEPT BIG RECORDS A LA UNIVAC JUNK

	DGT normally builds as task ...TPP and has many extra options.
The TPP HELP command will list them.
	One of its capabilities is to read Unix TAR format tapes when
given the T command. It will create a directory of the TAR tape if
asked to, read the whole tape into a directory, or read parts. When
in T mode it always creates SY:TARDIR.LIS, a directory containing the
Unix pathname, the RSX filespec it uses, the length of the file in
blocks, and an Ascii/Binary flag telling whether the file is binary
or not. Files it says are binary really are; some forms of files
it thinks are Ascii may be binary with unknown "magic numbers".
	The selective reading will read file SY:TARFIL.LST (which I
usually make by editing TARDIR.LIS) and copy any file where the first
character in the line in Tarfil.lst is a Y, skipping others. This will
let you pull pieces of a Tar tape in rather than create one huge directory
with possibly thousands of files from all over the place on a Unix file
structure.
	RSX filenames are taken from the last part of the Unix pathname
munged so funny characters get translated into 0,1,2, or 3. This works
with Tar tapes blocked up to (the standard) 20 disk blocks (10240 bytes).
