1   TAPCTRL
	A program to manipulate the structure of data on tape devices.

	To run this program you must declare two symbols:

		INTAPE :== 'INPUT_DEVICE'
		OUTAPE :== 'OUTPUT_DEVICE'

	Where the 'INPUT_DEVICE' is the device name of the tape drive
	to be used for input to other devices.  This device must be
	defined for the program to run.

	Where the 'OUTPUT_DEVICE' is the device name of the tape drive
	to receive data from the 'INPUT_DEVICE'.  This symbol may be
	defined either as a device or the command EXIT.  If defined
	as the command EXIT, you will only be able to view the data
	on the 'INPUT_DEVICE'.

	Both the 'INPUT_DEVICE' and optionally the 'OUTPUT_DEVICE'
	must be mounted on the system /FOREIGN.  The 'OUTPUT_DEVICE'
	should have write-ring if used.

	A command file TAPCTRL.COM is provided with this distribution.
2   General_Commands

	These commands apply to both the input and output command modes.

3   CLEAR

	Clears and re-paints the screen of the current command level.

3   REWND  

	This command rewinds the current command level device to the
	beginning of the tape.

3   SKIPF  

	This command skips the number of files requested.  The program
	will prompt for a number.  Negative numbers are valid.

3   SKIPR  

	This command skips the number of records requested.  The program
	will prompt for a number.  Negative numbers are valid.

3   READ   

	This command reads the current record into the Bufffer.

	It will display the first 80 characters of the Buffer.
	It also displays the first four bytes of the Buffer as
	a REAL*4 number.  Both items are displayed at the bottom 
	of a VT100 screen.

3   LOADF  

	This command copies the current Tape location till EOF.
	The data is stored in a VAX disk file you have named.

	This section of the program TAPCTRL is the same as the
	program LOAD.

3   FEOF   

	Finds next EOF mark on the current device.

	WARNING, if no EOF is present between the start position
	and the End-of-tape, the tape could run off the end of
	the reel.  This depends upon the presence of a EOT mark.

2   IN

	This sets the default device to the device declared as
	the input device at the beginning of the program.

	These command are in addition to the General commands,
	and assume that you have mounted an 'OUTPUT_DEVICE'.

3   WRITE  

	This command writes the information currently in the Buffer
	to the output device.  The READ Command should be used prior 
	to using this command.

3   COPYR  

	This Command Copies the number of records specified from the
	input device to the output device.  The copy operation starts
	at the current location on the 'INPUT_DEVICE' and copy the
	number of records requested or till an EOF condition is found.

3   COPYF  

	This command Same as LOADF, except the data image is written
	to the designated output device.  The copy operation starts
	at the current location on the 'INPUT_DEVICE' and copy the
	number of records requested or till an EOF condition is found.

3   WEOF   

	Writes EOF mark to current location of current device.

	WARNING, This may not be valid for writing to a device
	declared as being EBCDIC format.

3   LABEL  

	Allows for correction of LABEL on current device.

	WARNING, This is not valid for writing to a device
	declared as being EBCDIC format.

	Procedure:  (Recovery of data from bad tape)

		1.  Create a scratch tape with a correct label.
		2.  Use this scratch tape as your output device.
		3.  Set command level to OUT.
		4.  Invoke LABEL command.
		5.  Use copy commands to move files from input
		    to output device.

	Alternate:  (To just change label name)

		1.  Mount tape as input device.
		2.  Set command level to IN.
		3.  Invoke LABEL command.

2   OUT

	This sets the default device to the device declared as
	the output device at the beginning of the program.

2   EXIT   

	This Command causes the program to exit to the previous
	command level.  When in the command level for defining
	the device to access, this comman causes the program
	to stop.  In stopping the program, both tape devices are
	reset to the beginning of tape, and deallocated.

2   ASCII  

	This option sets a switch which tells the program that the
	data should be considered to have ASCII format.  The device
	will default to the input device unless otherwise specified.

2   EBCDI  

	This option sets a switch which tells the program that the
	data should be considered to have EBCDIC format.  The device
	will default to the input device unless otherwise specified.

