Commodore 1541-II - Appendix B: DOS Error Messages and Causes; Common DOS Error Codes and Troubleshooting

39: SYNTAX ERROR (invalid command)
The DOS does not recognize a command sent to the command channel (secondary
address 15). Check your typing and try again.
50: RECORD NOT PRESENT
The requested record number has not been created yet. This is not an error in a new
relative file or one that is being intentionally expanded. It results from reading past
the last existing record, or positioning to a non-existent record number with the
Record# command.
51: OVERFLOW IN RECORD
The data to be written in the current record exceeds the record size. The excess has
been truncated (cut off). Be sure to include all special characters (such as carriage
returns) in calculating record sizes.
52: FILE TOO LARGE
There isn't room left on the diskette to create the requested relative record.
To avoid this error, create the last record number that will be needed as you
first create the file. If the file is unavoidably too large for the diskette, either
split it into two files on two diskettes, or use abbreviations in the data to
allow shorter records.
60: WRITE FILE OPEN
A write file that has not been closed is being re-opened for reading. This file must
be immediately rescued, as described in Housekeeping Hint #2 in Chapter 4, or it
will become a splat (improperly closed) file and probably be lost.
61: FILE NOT OPEN
A file is being accessed that has not been opened by the DOS. In some such
cases no error message is generated. Rather the request is simply ignored.
62: FILE NOT FOUND
The requested file does not exist on the indicated drive. Check your spelling and try
again.
63: FILE EXISTS
A file with the same name as has been requested for a new file already exists on the
diskette. Duplicate file names are not allowed. Select another name.
64: FILE TYPE MISMATCH
The requested file access is not possible using files of the type named. Reread the
chapter covering that file type.
65: NO BLOCK
Occurs in conjunction with B-A. The sector you tried to allocate is already
allocated. The track and sector numbers returned are the next higher track and
sector available. If the track number returned is zero (0), all remaining sectors are
full. If the diskette is not full yet, try a lower track and sector.
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