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3.
Release interrupt. If AIOstatus bit2 is set, the device,
operating in dual access mode, has generated an inter-
rupt after its re lease by the other control! er.
4.
Attention interrupt. If AIO status bit 1 is set, the de-
vice has generated an interrupt as a result of the
depression 9f its manual ATTENTION pushbutton while
placing the device in the "operational" state (or after
the device was already operational).
TESTS FOLLOWING CHANNEL ENO OR UNUSUAL
. ENO INTERRUPTS
The following tests can be performed after receipt of a
channel end or an unusual end interrupt:
1.
CCl and CC2 are zero for an AIO instruction.
2.
AIO status bits 8,
9,
and 12 are zero.
3.
CC 1 and CC2 are zero for a TDV instruction.
4.
TDV status bits 8 through 15 are zero.
The testing described in this and the preceding section is
applicable to all peripheral devices. If no error is found,
device-dependent fault testing (see below) is not required.
PRIORITY OF DEVICE-DEPENDENT TESTING
One or more status bits may be set when a fault occurs.
Thus to properly describe the fault, testing must be per-
formed in a predefined sequence. Table 10 shows the test-
ing sequence priorities •
Before performing device-dependent testing, the program
must issue a TIO instruction to determine the state of the
device.
In case of software timeout, the TIO has a
I
ready
been issued.
The recovery actions annotated in Table 10 are more thor-
oughly described in the section subsequent to the table -
"Recovery Actions".
Table 10. Xerox Removable Disk Storage Systems Testing Sequence
.~
~
D.
-"
u
~
. .
-"
~
u
..5
5
~
. .
.!!
•O
~~
"'
~
0 ..
.g
""Cl
.~
""' a
....
·
0
-.; c
. .
~
""0
u
"'
...
-.:
~
-·
;;
;;
-"
:K'ii
~
""Cl
""Cl
""Cl
Sequence and Summary Description
Condition Code, Status Response Bits, and Detailed Information
..
cc
0
0
0
Recommended Corrective Action
J!
.. 0
. . . .
. . . .
V>U
"' "'
J:
J:
Step 1.
TDV CC1,CC2
01
x x x x x x
See recovery action l.
Perform if TDV CC 1, CC2
I
00,
in-
Test mode. The controller has been placed in test mode due to a
dicoting TDV condition code error.
hardware failure or a programming error.
TDV CC1,CC2
10.
x x
See recovery action
2.
Busy. The controller indicates
it is currently "busy" with a
x x x
See recovery action
4.
CJeV'lce other than the one addressed; this is the result of a hard-
x
See recovery action 3.
ware failure.
· - -
Step 2.
TIO 5,6 - 01.
x x x x x x
See recovery action l .
Perform if TIO 5, 6
I
00, indicating
Not
o~rational.
The controller has sensed that a power shutdown
control I er is not
11
ready
11
immediately
is in progress or that its control memory does not respond correctly.
following an
1/0
interrupt.
--
TIO 5,6' 10.
x x
See recovery action 2.
Not defined.
x x x
See recovery action 4.
x
See recovery action 3.
TIO 5,6
11.
x x
See recovery action 2.
Busy. The controller failed to return to the "ready
11
condition.
x x x
See recovery action 4.
flliScan occur if a command list is coded for multiple interrupts
x
See recovery action 3.
or
if
hardware malfunction prevented the controller's return to
the
11
reody
11
condition.
1/0
Fault Detection and Recovery Actions
35
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