You can do almost every file operation you do on files inside the machine. You need to add the correct file specifier though.
Example: saving a program to the cassette drive.
COPY MYPROG TO :TAPE(2) (copies to the second tape device
Other examples:
RENAME MYPROG:%16 TO MYPROG1
CAT :2 (cats the second unit on the loop)
device specifiers (arguments after the colon)
Address: Number, denutes the first, second, ...device on the loop
Assign code: uses assign codes, specified with ASSIGN IO
Device word: such as :TAPE , :MASSMEM, :TAPE(2) (2 = sequence number, the second tape on the loop)
Device ID: :HP82161A for the tape drive
Accessory ID: %16
Volume Label: use notation file.vol where file is the filename and vol is the volume label you assigned by initializing(formatting) the tape.
example: COPY MYFILE.MYVOL
copies this file from the media with label MYVOL into the 71
I don't know for now, if all mass media on the loop are searched searched for MYVOL, but I think so.
other example: CAT .MYVOL catalog on this media.
To format enter INITIALIZE :TAPE If you get error messages (too less space on drive) and you purged files from the tape before, you must pack the tape. Hey, this is not the NTFS system, not even FAT :-)
PACK :TAPE
This takes considerably long and puts some wear on the tape, so don't do this every day.
If other questions arise, don't hesitate to ask.