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See Figure 5-14 for reader/punch
operational flow.
The I/O operations required by the
1400 object program are performed by
their respective micro programs.
The
1400 I/O commands must be able to sense
status, perform the operation, and
detect any errors that occur during that
operation.
To further illustrate this
point, let us examine the 1402 opera-
tional flow chart.
Notice the micro
program will first define what operation
is to be performed.
Next, it fetches
the unit address from local storage and
issues a sense command.
The micro pro-
gram then examines the status byte com-
ing back to make sure the 1402 can
accept the
com~and.
If the 1402 status
is good, the command is given and the
micro program goes into a data loop.
While in the data loop, the micro pro-
gram is continually looking for a Chan-
nel End to occur.
The operation is
being done in burst mode because select
out cannot be reset.
When Channel End
occurs, the micro program gives the
statement FB->K, which resets select out
and allows the 1402 to drop-off the
channel.
The micro program will examine
the status byte that came with Channel
End to make sure the operation was per-
formed error free.
If not, the micro
program will go to an error routine to
display a coded byte in the R register
to indicate a 1402 error.
If the opera-
tion did occur error free, the micro
program goes back to interrogate the Cp
code again.
This is done to determine
whether or not it is a combined Cp
(read, punch, etc.).
If it was not a
combined Op, the micro program will exit
to I-cycles for the nex.t Op code.
Notice the micro program does not use
Device End at all.
The micro program
will accept Device End to get it off the
line, but does not use it because Chan-
nel End indicates the end of the opera-
tion.
1442 Reader/Punch Operation
When running the 1442 in compatibility
mode, there are two operational differ-
ences between the 1442 on the 1440 sys-
tem and the 1442 on a 2030 in compat-
ibility mode.
The 1442 when reading or
punching in compatibility mode: does not
stop on a column in error, but continues
to the end of the card'.
The micro pro-
gram tests for errors at the end of the
card operation.
The second difference
modifies the last card indication.
Last
card (end-of-file) occurs with the Chan-
nel End of the last card read.
The 34 MLP characters transmitted by
the 1442 are changed by the micro pro-
gram so that the 8-9 punches that desig-
nated the characters as MLP characters
are eliminated.
The characters in core
storage are the EBCDI equivalent of the
card code minus the 8-9 punches.
For
1442 operational flow, see Figure 5-16.
CHARACTER
CHARACTER
CHARACTER
CHARACTER
IN STORAGE
TO 1443
&
-
1
/
A
J
2
S
B
K
3
T
C
L
4
U
D
M
5
V
E
N
6
W
F
0
7
X
G
p
8
y
H
CD
Sent As 01000001
<b>
Sent As 11100001
&
-
0
A
J
/
1
B
K
S
2
C
L
T
3
D
M
U
4
E
N
V
5
F
0
w
6
G
P
X
7
H
Q
CD
®
IN STORAGE
TO 1443
Q
y
9
8
~
I
I
R
R
~
0
9
:j:
>
?
<
~
:j:
#
:
,
I
$
,
@
#
%
-
J::r
*
*
%
:
@
v
(
(
)
)
-v-
>
-v
\
+
<
;
;
-
'("""""""'
-
+++
*
*
I-
~
+
Blank
..-
Blank
Blank
J{
Blank
Figure 5-15.
52 and 63 Character
Typebar Decode
1443 Printer Operation
The character configuration of the
52- and 63-character type bar for the
1443 N1 is not the same as the 52-
and
63- character bar for the 1443 on the
1440 system.
To run the 1443
N1
in
compatibility mode, the 52- or
63-character bar for the 1440 system
must be installed in the 1443 N1.
Since
5-25
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