ZiLOG Z80-RIO Operating System User's Manual page 148

OPEN
OPEN
PROTECTION (code C3) - may occur as a disk
error if the diskette is write-protected, or
may occur by an attempt to open an existing
file which is write- or erase-protected for
output (thus deleting its records). In that
case, the file is opened but its records are
not deleted.
UNIT ALREADY OPEN (code CC) - the logical unit
is already active. It must be closed, or an
initialize operation must be performed, before
it can be OPENed again. No action is taken.
WRONG DISKETTE (code 01) - the disk ID of the
diskette in the drive does not match the ID in
memory. Usually indicates that the disks have
been switched since an INITIALIZE operation
was performed, or that a program has
overwritten the maps in memory. The file is
not opened.
FILE NOT FOUND (code C7) - the open request
was for input, and the file designated does
not exist.
POINTER ERROR (code CAl - could occur if the
pointers linking the segments of the directory
together have been destroyed or overwritten,
or if the file exists and the pointers for the
descriptor record are incorrect, or, in
deleting the records of an existing file, a
pointer mismatch occurs.
DUPLICATE FILE (code DO) - request to open a
new file when the file already exists. The
file is not activated.
INVALID ATTRIBUTE (code D2) - one of the
attributes specified for the creation of the
file was invalid. This may be that more than
one (or none) of the four mutually exclusive
types was specified, or that an invalid record
size was specified. The file is activated with
the defaults substituted for the erroneous
attributes.
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