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Upon Termination
When
of Operation at
During By
By
When
5ubch
Cmd
510
By
HID By I/O
I/O is is
Ctrl
I/O Chain- or
By
CLRIO or
Inter-
5tatus
Idle
Working 5ubch
Unit
Dev ing
510F TID +
HDV ruption
Attention
C*
C*
C*
5
5
5
5
5tatus modifier
C
C
C5
C5
5
C5
5
Control-unit end
C*
C5
C5
5
C5
5
Busy
C
C5
C5
5
C5
5
Channel end
C*
C*H
C*;t
C5;t
5
5
5
Device end
C*
C*
C ;t
C5;t
5
5
5
Unit check
C
C
C
C
C*
C5
C5
5
C5
Unit exception
C
C
C
C*
C5
5
5
5
Program-controlled
C*
C*
interruption
C
C5
5
5
5
Incorrect length
C
C
5
5
5
Program check
C
C
C*
C5
5
5
5
Protection check
C
C
C*
C5
5
5
5
Channel-data check
C
C
5
5
5
Channel-control check
C*
C*
C*
C*
C*
C*
C5
C5
C5
C5
C5
Interface-control check C*
C*
C*
C*
C*
C*
C5
C5
C5
C5
C5
Chaining check
C
C
5
5
5
Deferred cond code
1
C*#
5
5
5
Deferred cond code 3
C*#
5
5
5
Explanation:
C The
channel
or
device can create or present status at the indicated time.
A C5W
or its status portion is not necessarily stored at this time.
5tatus such as channel end or device end is created
at
the
indicated time.
Other
status bits may have been created previously
but are made accessible to the program
only at the
indicated
time.
Examples of such status bits
are
program
check and
channel-data
check,
which
are
detected
while
data is transferred
but are made
available to the program only with channel end, unless the PCI
flag or an equipment
malfunction has caused an interruption condition to be generated earl ier.
5 The status indication is stored in the C5W at the indicated time.
*
An
5 appearing alone
indicates that the
status has been created previously.
The
letter
C
appearing
with the
5
indicates that the
status did not
necessarily
exist previously in the
form that causes the
program to be alerted, and
may
have
been created by the I/O instruction or I/O interruption.
For
example, an equipment
malfunction may be detected during an
I/O
interruption, causing channel-control or
interface-control
check
to
be indicated; or a device such as the 2702 may
signal
control-unit busy in response to interrogation by an I/O instruction, causing status
modifier, busy, and control-unit end to be indicated in the C5W.
The status generates an interruption condition.
Channel
end
and
device
end do not result in interruption conditions when command
chaining is specified and no unusual situations have been detected.
;t
This indication is created at the indicated time only by an immediate operation.
# Applies only to 510F.
H When an operation on the selector channel has been concluded by HALT DEVICE or
HALT
I/O,
or
an
operation
has
been concluded by CLEAR I/O, channel end indicates the
conclusion of the data-handling portion of the operation at the control unit.
+ The entries in this column apply only when the CLRIO
function
is
executed.
When
CLEAR I/O
causes the
TID
function
to
be executed, the entries in the TID column
apply.
Contents of the CSW Status Fields
Chapter 12. Input/Output Operations
12-59
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