	TPT is a tape drive benchmark program that provides performance
statistics.  This program tests tape writes only.  Following is an example;
									       
$tpt :==$dev:[bodoh.eros3.tpt]tpt
$tpt mfa2: 65534 6250

Run summary:
	Drive:            MFA2:
	Blocksize:        65534

	Density:          6250
	Blocks written:   2560
	Bytes written:    167767040
	Tape used:        26842 inches for data
	                    768 inches for IRG
	                  -----
	                  27610 inches total (2300 feet)
	Elapsed time:     242 seconds
	Data rate:        693252 bytes/sec
	Transport speed:  114 IPS
	Errors:           0
	Last error:       1

      
	NOTES:								       
									       
	 - In the above example, 65534 is the blocksize.  This may be between  
 	   14 and 65534 inclusive.  Density may be 1600 or 6250, but defaults  
	   to 6250.							       
									       
	 - This test should be run on a completely idle system.  I/O contention
	   will cause more problems than CPU contention.  Make sure that no
	   other tape drives on the same controller/formatter are in use.
									       
	 - The size of the IRG (interrecord gaps) have been estimated.	       
									       
	 - Tape controllers which emulate DEC TS11 and use the DEC TSDRIVER    
	   cannot set density.  Default density is selected on the controller  
	   and is typically 6250, but may be overidden on the front panel of   
	   the drive.							       
									       
	 - This program buffers up to 32 writes in order to get maximum tape   
	   speed.  We use event flags 32 through 63 since event flags 24       
	   through 31 are reserved for system use, and we want to allow the    
	   program to use a contiguous block of event flags.		       

	 - TPT only uses 2300 feet of tape.				       

	 - Due to the fact that we are buffering 32 writes, when we hit 2300
	   feet, we may actually write up to 32 records before the cancel I/O
	   takes effect.  This will not throw off the calculations since the
	   I/O's are not counted until the event flag is checked.

	 - Since TPT is typically run several times in a test, it dismounts
	   the tape with nounload.  If run interactively, TPT will not
	   return to the DCL prompt until the tape rewinds.
