Notes
(Cont'd)
Privileged
Instructions
The
standard
device byte is stored
under
the
following conditions:
a. The specified device control electronics
on
the
multiplexor
chan-
nel indicates
that
a device
request
interrupt
pending
condition
is present. The
external
device request
interrupt
pending
bit
in
the
standard
device
byte
is set.
b. The specified device is busy
but
the
device control electronics is
not
busy (Le.,
tape
rewinding, off-line seek to a
random
access
device). The device
busy
bit
in
the
standard
device
byte
is set.
c.
The specified device is inoperable. The device inoperable
bit
in
the
standard
device byte is set.
6.
Condition Code 2 is
set
under
the
following conditions:
a. A selector channel is specified
that
is busy.
b. A selector
channel is specified
that
has
an
interrupt
pending
(termination
or
external
device request.)
c.
The multiplexor channel is specified
and
it
is
operating
in
burst
mode.
d.
The multiplexor channel is specified
and
the
addressed device
control electronics is busy
with
addressed
or
non-addressed device.
e.
The multiplexor channel is specified
and
the
addressed device
control electronics
has
a
termination
interrupt
pending.
7.
Condition Code 3 is
set
under
the
following conditions:
a. A selector channel is specified which is
not
in
the
system.
b. The specified device control electronics is inoperable.
c.
A device is specified
that
is
not
in
the
system.
114
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