Commodore 16 User Manual page 85

20 READ ERROR
(block header not found)
21 READ ERROR
(no sync character)
22 READ ERROR
(data block not present)
23 READ ERROR
(checksum error
En data block)
24 READ ERROR
(byte decoding error)
The disk controller is unable to lo-
cate the header of the requested
data block. Caused by an illegal
sector number, or the header has
been destroyed
The disk controller is unable to
detect a sync mark on the desired
track. Caused by misalignment of
the read/writer head, no diskette
is present, or unformatted or im-
properly seated diskette. Can
also indicate a hardware failure.
The disk controller has been re-
quested to read or verify a data
block that was not properly writ-
ten. This error message occurs
in conjunction with the BLOCK
commands and indicates an ille-
gal track and/or sector request
This error message indicates that
there is an error in one or more of
the data bytes The data has been
read Into the DOS memory, but
the checksum over the data is in
error This message may also in-
dicate grounding problems.
The data or header has been read
into the DOS memory, but a hard-
ware error has been created due
to an invalid bit pattern in the data
byte. This message may also
indicate grounding problems.
This message is generated it the
controller detects a mismatch
between the written data and the
data in the DOS memory.
This message is generated when
the controller has been requested
to write a data block while the
write protect switch is depressed.
Typically, this is caused by using
a diskette with a write protect
tab over the notch
The controller has detected an
error in the header of the re-
quested data block. The block
has not been read into the DOS
memory This message may also
indicate grounding problems.
The controller attempts to detect
the sync mark of the next header
after writing a data block. if the
sync mark does not appear within
a pre-determined time. the error
message is generated. The error
is caused by a bad diskette format
(the data extends into the next
block), or by hardware failure.
This message is generated when
the controller has been requested
to access a diskette which has
not been initialized. The message
can also occur if a diskette has a
bad header
The DOS cannot interpret the
command sent to the command
channel. Typically, this is caused
APPENDIX B
Disk Error Messages
These error messages are returned through the DS and DS$
reserved variables
NOTE: Error message numbers less than 20 should be ignored
with the exception of 01, which gives information about the num-
ber of files scratched with the SCRATCH command
25
WRITE ERROR
(wweverify error)
26 WRITE PROTECT ON
27 READ ERROR
(checksum error
in header)
28 WRITE ERROR
(long data block)
29
DISK ID MISMATCH
30
SYNTAX ERROR
(general syntax)
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