C:\> robtest.exe
Configured robots with local control supporting test utilities:
  TLD(0)     robotic path = {2,0,0,0}

Robot Selection
---------------
  1)  TLD 0
  2)  none/quit
Enter choice: 1
1

Robot selected: TLD(0)   robotic path = {2,0,0,0}

Invoking robotic test utility:
C:\Program Files\VERITAS\Volmgr\bin\tldtest.exe -rn 0 -r {2,0,0,0}

Opening {2,0,0,0}
MODE_SENSE complete
Enter tld commands (? returns help information)
s d
drive 1 (addr 500) access = 1 Contains Cartridge = no
drive 2 (addr 501) access = 1 Contains Cartridge = no
READ_ELEMENT_STATUS complete
m s1 d1
Initiating MOVE_MEDIUM from address 1000 to 500
MOVE_MEDIUM complete

C:\>/cygdrive/c/Program Files/VERITAS/Volmgr/bin
$ nt_ttu.exe

Welcome to nt_ttu, h[elp] or ? for help.

Data Buffer Initial Address - 8f4000

nt_ttu> p
        Current filename for testing = \\.\tape0.
        Filename is NOT open.
        Data buffer address       = 8f4000
        Maximum buffer size bytes = 262144(10) or 40000(h).
        Current record byte count = 4096(10) or 1000(h).
        Capacity = 3141533696d.
        Space remaining = 2120220672d.
        Blocksize = 0 (variable-length mode).
        Number of partitions = 0.
        Media is not write-protected.
        Drive does not support hardware error correction.
        Hardware data compression is enabled.
        Data padding is disabled.
        Setmark reporting is disabled.
        Default blocksize = 32768
        Maximum blocksize = 16777215
        Minimum blocksize = 1
        Maximum partition count = 1
        End of Tape (EOT) warning zone size = 0

nt_ttu>

Bruce, the important param is "Maximum blocksize = 16777215".