The Apollo version uses the stream I/O routines available in
the system library. The files written by EPIO are of type REC (variable
record length) but even UASC files can be handled provided the
logical block length is fixed and the first status word is properly set.
The default file name is FORnnn.DAT like on the VAX where nnn
is the logical unit number.
This can be changed by calling EPDEFU.
Tapes are accessed via a magnetic tape descriptor file. The EPIO routines address the file which in turn redirect the I/O operation to the physical device. A magnetic tape descriptor file is created by the command:
edmtdesc for011.dat -c -s lab no reo no civ yes spos yes edmtdesc for011.dat -s f 1 rf u bl 3600 rl 3600 ascni no
This is the case for a standard EPIO unlabelled tape recorded with
a blocksize of 3600 bytes. In case of label or of different blocksize
the parameters should be changed accordingly.
Type Help EDMTDESC for
more details. The name of the Magnetic tape descriptor file can
be different from FORnnn.DAT provided the user calls EPDEFU.