The Write Data command operates in much the
same manner as the Read Data command. The
following items are the same. Please refer to the
Read Data Command for details:
like a Read Data command except that no data
is transferred to the host. Data is read from the
disk and CRC is computed and checked against
the previously-stored value.
Transfer Capacity
EN (End of Cylinder) bit
ND (No Data) bit
Head Load, Unload Time Interval
ID information when the host terminates the
command
Definition of DTL when N = 0 and when N does
not = 0
Write Deleted Data
This command is almost the same as the Write
Data command except that a Deleted Data
Address Mark is written at the beginning of the
Data Field instead of the normal Data Address
Mark. This command is typically used to mark
a bad sector containing an error on the floppy
disk.
Verify
The Verify command is used to verify the data
stored on a disk. This command acts exactly
Because data is not transferred to the host, the
TC cycle cannot be used to terminate this
command. By setting the EC bit to "1", an
implicit TC will be issued to the FDC. This
implicit TC occurs when the SC value
decrements to 0 (an SC value of 0 will verify 256
sectors). This command can also be terminated
by setting the EC bit to "0" and the EOT value
equal to the final sector to be checked. If EC is
set to "0", DTL/SC should be programmed to
0FFH. Refer to Table 27 and Table 28 for
information concerning the values of MT and EC
versus SC and EOT value.
Definitions:
# Sectors Per Side = Number of formatted
sectors per each side of the disk.
# Sectors Remaining = Number of formatted
sectors left which can be read, including side 1
of the disk if MT is set to "1".
Table 28 - Verify Command Result Phase
MT
EC
SC/EOT VALUE
TERMINATION RESULT
0
0
SC = DTL
Success Termination
EOT ≤ # Sectors Per Side
Result Phase Valid
0
0
SC = DTL
Unsuccessful Termination
EOT > # Sectors Per Side
Result Phase Invalid
0
1
SC ≤ # Sectors Remaining AND
Successful Termination
EOT ≤ # Sectors Per Side
Result Phase Valid
0
1
SC > # Sectors Remaining OR
Unsuccessful Termination
EOT > # Sectors Per Side
Result Phase Invalid
1
0
SC = DTL
Successful Termination
EOT ≤ # Sectors Per Side
Result Phase Valid
1
0
SC = DTL
Unsuccessful Termination
EOT > # Sectors Per Side
Result Phase Invalid
1
1
SC ≤ # Sectors Remaining AND
Successful Termination
EOT ≤ # Sectors Per Side
Result Phase Valid
1
1
SC > # Sectors Remaining OR
Unsuccessful Termination
EOT > # Sectors Per Side
Result Phase Invalid
Note: If MT is set to "1" and the SC value is greater than the number of remaining formatted sectors
on Side 0, verifying will continue on Side 1 of the disk.
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