Hi,
        We tried to find the optimum block size for 3590 tape drive used by 
ADSM. Right now we have it
set at 1024, and so are all our backup tapes. We are thinking about changing it 
to larger block size
like around 6000, supposingly this will increase our I/O by a factor of 4. Our 
initial test has shown that
using the Unix dd command, the I/O does increase.
        Any advice on this matter is greatly appreciate, thanks. PC.