RCA 70/46 Reference Manual page 118

Notes
(Cont'd)
Privileged
Instructions
a. The device control electronics and the device specified are
available.
b. The Start Device instruction specifies a Sense command to a
device that is inoperable.
5. Condition Code 1 indicates that either the channel status byte or
the standard device byte has been stored in the channel registers in
scratch-pad memory for the specified channel.
The channel status byte is stored under the following conditions:
a. A parity error occurs while accessing the Channel Address Word
(CAW), Channel Block Address (CBA), or a Channel Command
Word (CCW). The channel control check bit in the channel status
byte is set.
b. The Memory Protect feature is not installed and the key in the
CAW is not zero. The program check bit in the channel status
byte is set.
c. The main memory address specified in the CAW or CBA is not
on a double word boundary. The program check bit in the channel
status byte is set.
d. The main memory address in the CCW specifies an address out-
side the available memory for the system. The program check
bit in the channel status byte is set.
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 Start Device instruction specifies a command which is other
than a Sense command and the addressed device is inoperable.
The device inoperable bit in the standard device byte is set.
c. The specified device is busy but the device control electronics is
not busy (Le., tape rewinding, off-line seek to a random access
device end bit in the standard device byte are 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 con-
trol electronics has a termination interrupt pending.
f. A burst mode operation is directed to the multiplexor and there
is a termination interrupt pending on one of the attached device
control electronics.
7. Condition Code 3 is set under the following conditions:
a. A selector channel is specified that is not in the system.
b. The specified device control electronics is inoperable.
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