All of our 8mm tape drives on all of our RS/6000s are defined as
/dev/rmt0.  The ADSM Administrator' Reference (page 96), referring
to the DEFINE DRIVE command says "For 8mm tape drives, you must
specify the device name having the form /dev/mtX....  DO NOT enter
a device name that has the form /dev/rmtX."  Is there a secret way
to get AIX to define an 8mm drive as "mt" instead of "rmt"?

The ADSM Administrator's Guide (page 161) tells how to configure a
standalone SCSI tape drive.  It simply describes the standard way
we have defined all our 8mm drives.  And, of course, they end up
defines as "rmt".

When I issue the command:
    define drive manlib tapedrive1 device=/dev/mt0
or: define drive manlib tapedrive1 device=/dev/rmt0
I get the same error:
ANR8420E DEFINE DRIVE: An I/O error occurred while accessing drive TAPEDRIVE1.

There must be a simple answer to this?