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Sequence and Summary Description
Step 6.
Performed only if TDV 6 / 0,
indicating a Seek Timeout.
Step 7.
Performed only if TDV 7 / 0,
indicating a header parity error.
Step 8.
Performed only if TDV 4
IO.
Sense Byte 8, bits 2, 3, and 4
indicate, respectively, the error
as sector head, or cylinder (see
Table 3).
Step 9.
Performed only if TDV l
I
0,
indicating a flaw mark.
Step 10.
Performed only if OSB
I
0
(Sigma 3) or TDV 9 / 0
(Sigma 5-9), indicating a
Transmission Data error.
Note: OSB = Operational
Status Byte
Table 9. Removable Disk Storage System Testing Sequence
(c~nt.)
Condition Code, Status Response Bits and Detailed Description
Seek Timeout. A hardware seek timeout has been detected because
the on-cylinder device state has failed to occur after head motion
has started. This is a hardware malfunction.
Header Parity Error.
A
parity error in the header has been detected,
indicating that the header portion of the sector cannot be read
correctly.
Header Verification Error. This error may occur during a surface,
Header Read, or Sense operation, In all cases, the current surface
address is not incremented.
Surface Operations. For the first surface operation after a Seek
operation, the header verification error indicates a sector header
corresponding to the addressed surface could not be found in any of
the six sectors of the addressed cylinder and head. After the first sur-
face operation, the header verification error indicates the header of the
currently addressed sector
1
s header is incorrect. In either case, the
surface operation has not been performed.
Header Read Operations. The header verification error during the
Header Read operation indicates that the currently addressed sector
1
s
header is incorrect.
Sense Operations, The header verification error during the Sense
operation indicates that a header has been read whose cylinder and
head field does not compare with the current cylinder and head
address. This header may be any of the six headers of the cylinder
and head.
Flaw Mark, A flaw mark has been detected during a surface, Header
Read or Sense operation. In all cases, the current surface address is
not incremented.
Surface Operations. For the first surface operation after a Seek
operation, the flaw mark indicates a flaw has been detected in a
sector's header of the addressed cylinder and head while the sector
headers were being scanned to obtain the addressed sector.
On
sub-
sequent operations, the flaw mark indicates the currently addressed
sector
1
s header contains a flaw. This condition will be present when
the surface address has been incremented from an unflawed cylinder
and head to a flawed cylinder and head surface. In either case, the
surface operation is not performed.
Header Read Operations.
~law
mark has been detected in the cur-
rently addressed sector. This indicator should not be considered an
error.
Sense Operations. Flaw mark during a Sense operation indicates that
a header has been read containing a flaw. This header may be any of
the six headers of the currently addressed cylinder and head. The
flaw mark indication should not be considered an error.
Transmission Data Error. This error may be caused by any of the
following:
a.
Data Over-Run. When the system fails to maintain data
transfer rate required during Read, Write, Checkwrite,
Header Read, or Header Write operation.
(TDVO will also
be set to a
l.)
b.
Data Parity Error. The sector data parity has failed to
compare to the expected parity during a Read, Checkwrite,
or Header Read operation. (Bit 0 of Sense Byte 8 is also
set to a l.)
c.
Checkwrite Error. When a data comparison error occurs
during a Checkwrite operation. (Bit 1 of Sense Byte 8 is
also set to a 1.)
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Recommended Corrective Action
I
x
Use Recovery Procedure 3.
x
Use Recovery Procedure 2.
x
Use Recovery Procedure 2.
Use Recovery Procedure 3.
x
Use Recovery Procedure 2.
Use Recovery Procedure 3.
x
Use Recovery Procedure 6.
Use Recovery Procedure 5.
x
Use Recovery Procedure 4.
Use Recovery Procedure 4.
Use Recovery Procedure 4.
I/O faults and Recovery Procedures
27
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