Commodore 128 System Manual page 375

71: DIRECTORY ERROR
The BAM (Block Availability Map) on the diskette
does not match the copy on disk memory. To
correct, initialize the diskette.
72: DISK FULL
Either the blocks on the diskette are used or
the directory is at its entry limit. DISK
FULL is sent when two blocks are still available
on the diskette, in order to allow the current
file to be closed.
73: DOS MISMATCH (VERSION NUMBER)
DOS 1 and 2 are read compatible but not write
compatible. Disks may be interchangeably read
with either DOS, but a disk formatted on one
version cannot be written upon with the other
version because the format is different. This
error is displayed whenever an attempt is made
to write upon a disk which has been formatted
in a non-compatible format. This message will
also appear after power up and is not an error
in this case.
74: DRIVE NOT READY
An attempt has been made to access the disk
drive without any inserted; or the drive lever
or door is open.
B-5