Terry,

The thing you're looking for is forcing both Legato AND windows to use a 
different block size. The problem here is that a lot of Host Bus Adapter 
drivers (SCSI/FC) are not configured to allow a large blocksize and as 
such default to a maximum of the well known Windows 64k.

You can add a registry key to the HBA driver to allow for bigger 
blocksizes:

HKLM\SYSTEM\CurrentControlSet\Services\<scsidriver>\parameters\device; add 
DWord MaximumSGList=FF)

Use the following command to check whether your maximum blocksize is 
limited to a lower (=<64k) value:
mt -f \\.\Tape0 status 

So if you set MaximumSGList to FF, Legato Networker can then successfully 
write bigger blocks to the tape device when instructed to via the 
NSR_DEV_BLOCK_SIZE_<media type> environment variable.

A windows setting to default all windows operations to write at bigger 
blocksizes is unknown to me.

To sign off this list, send email to listserv AT listserv.temple DOT edu and 
type "signoff networker" in the
body of the email. Please write to networker-request AT listserv.temple DOT edu 
if you have any problems
wit this list. You can access the archives at 
http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER