When a programming error occurs in the inform a -
tion placed in theCAW or ccw and the addressed
channel or sub channel is working, either condition
code 1 or 2 may be set, depending on the model.
Similarly, either code 1 or 3 may be set when a pro
gramming error occurs and a part of the addressedI/O system is not operational.
When a programming error occurs and the ad
dressed device contains an interruption condition,
with the channel and sub channel in the available
state,START I/O mayor may not clear the interruption
condition, depending on the type of error and the
model. If the instruction has caused the device to be
interrogated, as indicated by the presence of the busy
bit in the csw, the interruption condition has been
cleared, and the csw contains program check, as well
as the status from the device.
When the channel detects several error conditions,
all conditions may be indicated or only one may ap
pear in the csw, depending on the condition and the
model.Parity errors detected by the channel on data sent to
or received from theI/O device on some models cause
the current operation to be terminated. When the
channel and theCPU share common equipment, parity
errors on data may cause malfunction reset to be per
formed. The recovery procedure in the channel and
158
subsequent state of the sub channel upon a malfunc
tion reset depend on the model.
Detection of channel control check or interface con
trol check causes the current operation, if any, to be
immediately terminated and causes the channel to per
form the malfunction-reset function. The recovery pro
cedure in the channel and the subsequent state of the
sub channel upon a malfunction reset depend on the
model.
The contents of the csw, as well as the address in
the psw identifying theI/O device, are unpredictable
upon the detection of a channel-control-check con
dition.
Execution of malfunction reset in the channel de
pends on the type of error and model. It may cause
all operations in the channel to be terminated and all
operational subchannels to be reset to the available
state. The channel may send the malfunction-reset
signal to the device connected to the channel at the
time the malfunctioning is detected, or a channel shar
ing common equipment with theCPU may send the
system-reset signal to all devices attached to the chan
nel.
The method of processing a request for interruption
due to equipment malfunctioning, as indicated by the
presence of the channel-data-check, channel-control
check, and interface-control-check conditions, depends
on the model. In channels sharing common equipment
with theCPU, malfunctioning detected by the channel
may be indicated by the machine-check interruption.
tion placed in the
channel or sub channel is working, either condition
code 1 or 2 may be set, depending on the model.
Similarly, either code 1 or 3 may be set when a pro
gramming error occurs and a part of the addressed
When a programming error occurs and the ad
dressed device contains an interruption condition,
with the channel and sub channel in the available
state,
condition, depending on the type of error and the
model. If the instruction has caused the device to be
interrogated, as indicated by the presence of the busy
bit in the csw, the interruption condition has been
cleared, and the csw contains program check, as well
as the status from the device.
When the channel detects several error conditions,
all conditions may be indicated or only one may ap
pear in the csw, depending on the condition and the
model.
or received from the
the current operation to be terminated. When the
channel and the
errors on data may cause malfunction reset to be per
formed. The recovery procedure in the channel and
158
subsequent state of the sub channel upon a malfunc
tion reset depend on the model.
Detection of channel control check or interface con
trol check causes the current operation, if any, to be
immediately terminated and causes the channel to per
form the malfunction-reset function. The recovery pro
cedure in the channel and the subsequent state of the
sub channel upon a malfunction reset depend on the
model.
The contents of the csw, as well as the address in
the psw identifying the
upon the detection of a channel-control-check con
dition.
Execution of malfunction reset in the channel de
pends on the type of error and model. It may cause
all operations in the channel to be terminated and all
operational subchannels to be reset to the available
state. The channel may send the malfunction-reset
signal to the device connected to the channel at the
time the malfunctioning is detected, or a channel shar
ing common equipment with the
system-reset signal to all devices attached to the chan
nel.
The method of processing a request for interruption
due to equipment malfunctioning, as indicated by the
presence of the channel-data-check, channel-control
check, and interface-control-check conditions, depends
on the model. In channels sharing common equipment
with the
may be indicated by the machine-check interruption.
