The AMTHD option specifies the access method to access the data set.
.-FSYS----. >>-AMTHD--(-+-ISAM----+-)-------------------------------------->< +-BTRIEVE-+ '-REMOTE--'
For Windows, the name of the file needs to be qualified by the LU alias or the fully-qualified SNA network name
FSYS is used by default if you do not specify the AMTHD option and if you do not apply one of the following ENVIRONMENT options:
If you specify any of the above options, AMTHD(ISAM)is the default on Windows while AMTHD(DDM) is the default on AIX.