If u specifies an external unit that is not connected to a file, an implicit OPEN operation is performed that is equivalent to opening the file with the following options:
OPEN(u , FILE='FORT.u ', STATUS='UNKNOWN', & ACCESS='SEQUENTIAL', FORM=fmt )
The value of fmt is 'FORMATTED' if the write is formatted, and 'UNFORMATTED' otherwise.
A simple unsubscripted array name specifies all of the elements of the array in memory storage order, with the leftmost subscript increasing more rapidly.
The record number for direct-access files starts from one onwards.
Namelist-directed output is permitted on sequential access files only.