IBM System/360 2050 User Manual

Skipping Bad FLT Records
If a record on tape or disk cannot be read in cor-
rectly, and it is desired to skip that record and read
in the next record, the following procedure must be
followed:
For Tape: With the FLT control switch not on auto
reread, depress the system reset PB and then de-
press the load PB.
For Disk: With the FLT control switch not on auto
reread, set the FLT mode switch to the force pass
position and depress the system reset PB. (This
steps the cylinder counter up by one.) Next, set the
FLT mode switch back to the load position and then
depress the load PB.
Disk (FLT) Operating Procedures
The following procedures are for disk-originating
FLT's and are not to be confused with the tape-
originating FLT procedures which precede this
section.
MS Mode Hardcore (Disk): For stops and loops not
identified in this section, refer to the main store
hardcore listing (FLTOl) and check the stop codes to
identify the failure.
1. Mount disk pack No. 1 containing the MS
hardcore tests on a disk drive attached to a selector
channel, start motor, and wait until unit is ready.
2. Select the channel and disk drive address
with the load unit switches (switch labeled 0-7 selects
the channel).
3. Press system reset with the FLT mode
switch in neutral.
4. Place the FLT mode switch in the load posi-
tion.
5. Place the FLT control switch in the halt-
after-load position.
6. Place the check control switch in the stop
position.
7. Press the load key. The first record of MS
hardcore is read into storage and the following indi-
cators should now be on:
a. Sequence counter indicators 1 and 2
(equal 3).
b. Sequence stat 3.
c. Sequence counter mode.
d. Load light.
IAR should equal 024 (1st pack only).
IAR should equal 4V8C (2nd and 3rd packs).
8. Return the FLT control switch to process if
the load was successful; otherwise, repair the load
circuitry and reload (Figure 26).
9. Press start.
a. Record 1 is executed. If successful,
record 1 calls in record 2 which, if success-
ful, calls in record 3.
b. Record 3 will stop three times for ROS
words FD5, FD6, and FD7. These words
have bad parity to test ROS parity check cir-
cuits.
10. At the first stop, the hard stop indicator
should be on.
11. Turn CPU roller 2 to display current ROS
address (row 7).
12. Depress the force indicator lever switch;
the ROS address shown should be FD5.
13. Press start. The ROS address should be
FD6 and the hard stop indicator should be on.
14. Press start. The ROS address should be
FD7 and the hard stop indicator should be on.
15. Press start. SDR indicates a successful stop
as follows:
p
p p p
lFF OFF lFF lFF
MS Mode ROS Bit Tests (Disk): The SDR is used for
error analysis and error indications. See the main
store mode ROS bit test listing (FL T04) for stops and
loops not identified.
1. Press start (following a successful halt of
MS hardcore tests).
2. ROS bit test record 1 loads, executes, and
calls for the next record.
3. ROS bit test records continue to be executed
until the termination record is sensed at the end of
the disk pack. If no stops occurred, disk pack No. 1
successfully checked out ROS bits for planes 0-5.
IAR 004
SDR P P P P
lFF OFF lFF lFl
4. Remove disk pack No. 1 and mount disk pack
No. 2, start disk drive motor and wait for the unit
to become ready.
5. Repeat steps 2-8 as described under "MS
Mode Hardcore (Disk)."
6. Press the start key.
7. ROS bit records continue to be executed until
the termination record is sensed at the end of the
disk pack. If no stops occurred, disk pack No. 2
successfully checked out ROS bits for planes 6-B.
IAR 004
SDR P P P P
lFF OFF lFF 1F2
Maintenance Features (3/71) 57

IBM System/360 2050 Specifications

General

Brand	IBM
Model	System/360 2050
Category	Computer Hardware
Language	English