The ACCESS=acc clause is optional. acc is a character expression. Possible values are: APPEND, DIRECT, or SEQUENTIAL. The default is SEQUENTIAL.
If ACCESS='APPEND': SEQUENTIAL and FILEOPT='EOF' are assumed. This is for opening a file to append records to an existing sequential-access file. Only WRITE operations are allowed. This is an extension and can be applied only to disk files. @
If ACCESS='DIRECT': RECL must also be given, since all I/O transfers are done in multiples of fixed-size records.
Only directly accessible files are allowed; thus, tty, pipes, and magnetic tape are not allowed. If you build a file as sequential, then you cannot access it as direct.
If FORM is not specified, unformatted transfer is assumed.
If FORM='UNFORMATTED', the size of each transfer depends upon the data transferred.
If ACCESS='SEQUENTIAL', RECL is ignored. @ The FORTRAN 77 Standard prohibits RECL for sequential access.
No padding of records is done.
If you build a file as direct, then you cannot access it as sequential.
Files do not have to be randomly accessible, in the sense that tty, pipes, and tapes can be used. For tapes, we recommend the TOPEN() routines because they are more reliable.
If FORM is not , formatted transfer is assumed.
If FORM='FORMATTED', each record is terminated with a newline (\n) character; that is, each record actually has one extra character.
If FORM='PRINT', the file acts like a FORM='FORMATTED' file, except for interpretation of the column-1 characters on the output (blank = single space, 0 = double space, 1 = form feed, and + = no advance).
If FORM='UNFORMATTED', each record is preceded and terminated with an INTEGER*4 count, making each record 8 characters longer than normal. This convention is not shared with other languages, so it is useful only for communicating between FORTRAN programs.