Bad Spots On Disk; No Record Found (2) Error; Seek (3) Error; Disk Read (4) Error - IBM 3741 Data Station Reference Manual

4.
Modify the EOD field in the data set label with the
recorded address.
5. Execute a search EOD operation to validate the EOD
address.
6.
If the operator had originally keyed over currently
valid data, the records should be examined and
corrected.
On occasion, an operator will remove a diskette from the
disk drive before pressing RETURN TO INDEX. When
this happens, there is the possibility that the EOD address
will not be correct because the only time that the address
is updated is when the return to index function is perform·
ed. The preceding procedures should also be used for this
situation.
BAD SPOTS ON DISK
If a record cannot be read from or written onto disk, the
copy function can be used to copy surrounding data and
then manually key the bad record. Alternate methods
depend on the mode the station is in when the error occurs:
Enter mode - return to index and continue the batch on a
new diskette. Verify or Update mode - backspace several
records and then record advance to see if the problem wi II
clear itself; if not, delete the record and add it to the data
set (see
Adding Records to
a
Batch
in this section).
The following are recovery procedures to follow when disk
errors 2, 3,4, and 5 persist.
No Record Found (2) Error
A no record found error occurs when the address that
identifies the location of a record on disk is defective.
• If the error occurs when record advancing in update
mode, the display is blank.
• If the error occurs when record backspacing in enter or
update mode, the record displayed when the record back·
space key was pressed remains displayed.
• For verify mode, the record on which the no record
found error occurred is the next record to be verified
not the current record being verified- and displayed. '
The operator can reset the error, complete verification
of the current record, and press R EC ADV. The record
displayed after pressing R EC ADV is the record just
verified.
• For all other modes, the record read prior to the no
record found error is displayed.
When the no record found error persists, perform the
appropriate copy operation to copy the data. The IBM
3741 Data Station Operator's Guide, GA21·9131 provides
copy procedures.
Follow the procedures in the operator's guide for error
recovery when the no record found error occurs while
copying. Be sure to identify the diskette on which the no
record found error occurred as being defective. The defec·
tive diskette should be initialized.
Seek (3) Error
A seek error occurs when the address that identifies a track
is defective. When the seek error occurs, the 3741 either
returns to the index track or remains within the data set
depending on the mode of operation. When the seek error
persists, perform the appropriate copy operation to copy
all of the disk. The
IBM
3741
Data Station Operator's
Guide,
GA21·9131 provides copy procedures. Follow the
procedures in the operator's guide for error recovery when
the seek error occurs while copying. Be sure to identify
the diskette on which the seek error occurred as being
defective. The defective diskette should be initialized.
Disk Read (4) Error
A disk read error occurs because a portion of the record, or
the entire record read is in error. However, the record on
which the read error occurred is displayed even though a
portion or all of the record is in error. If the read error
persists after being reset several times, the following can
be performed to try and correct the error.
Note:
For verify mode, the record on which the read error
occurred is the next record to be v.erified, not the current
record being verified and displayed. Therefore, the operator
can reset the error and complete verification of the record
and then press R EC ADV. The record on which the
read error occurred is then displayed.
If you can identify what data is incorrect in the record,
correct the data and press record advance. If no write error
(5) occurs, the record has been written to disk correctly and
it should be read properly.
Operation Modes and Considerations 23