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Bit
'12, 11,
10,
9
(Coordina-
tion message)
(cont'd)
I
13
(Terminate
CCW)
14
(Exclude
Control Char-
acter block
parity)
Table 3-5
Optional Word 1 (OW-I)
Function
0010
0011
through
1111
1
an (FF)16 and bit 16 of LSW B (error recording)
will have been set; whenever LSW B 16 is set,
if a good message is requested it is changed to
a bad message in the CRB.
If a good message
has not been requested, the hardware generates
bad message CMs only_
(Upon CM generation, LSW
B
16 is reset to zero).
For systems using block parity, a good message
and bad message CM's are generated automatically
by the hardware, the 0001 bit setting in the
OP WORD is not necessary and should not be used.
(Bad Message - Bad Parity)
Because this bit con-
figuration may be automatically generated by
the hardware, it should not be used to indicate
other "bad messages" say those which are termina-
ted by a
CAN
(cancel) character unless it is
unnecessary to distinguish between bad messages
with parity errors and other bad messages.
If a
bad message CM is requested (OP WORD bit setting
0010) and a parity error (character and/or block)
occurs, two bad message CMs are sent:
one caused
by the request (0010), the other caused by the
error.
These settings are available to the program as
desired, but certain software systems may by
convention reserve some of these settings for
specific use.
When permitted by the action control bits,
terminate the existing channel command word
(CCH) .
o
No Action
The
fol1ow~ng b~ts
are not subject to-the
act~on"
control bits (2, 1, 0)
j
their functions are performed
whenever the OP WORD is called up by a control character:
1
Note:
a
Exclude the control character which fetched
this Op Word from the block count.
This bit and bit
a
of OW 2 must not be both equal
to 1.
Include the character in the block parity count.
(Use
a
setting for non-block parity systems.)
15
1
Effective only during a Read CCW, inhibit trans-
fer of the control character to the processor.
(Control characters, those characters which
fetch Op Words, are transferred to the processor
regardless of the In/Out of Data Block setting
(Delete Control
Character)
OW-l
a
((LSWC 13)} unless inhibited by this bit.)
Transfer the control character to the processor.
7
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