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This section is concerned with instructions for 1620
input/output units. Complete operating details for
these units are described in the
IBM
publications on
the cover page of this manual.
1620 Input/Output instructions enable the transfer
of data between core storage and disk storage, and
core storage and input/output units. The Read in-
structions transfer data from the input unit to core
storage, and the Write and Dump instructions trans-
fer data from core storage to the output unit. The
Q8
and
Q9
digits specify the
I/O
unit; as follows:
01 - Typewriter
02 - Tape Punch
ft
02 - Plotter
ft
03 - Paper Tape Reader
ft
04 - Card Punch
05 - Card Reader
07 - 1311 Disk Storage Drive
09 - 1443 Printer
I
OP
\
P
\Q81 Q 91 IQlll
~
~
"-v--'
I/O
Core
I/O
1311 and
Codes
Storage
Unit
1443
( 35-39)
Address
Modifier
The
Qll
position of the instruction is used to define
1311 operations and 1443 carriage spacing. Although
the 1311 is controlled with standard input/output
codes (36 and 38) and
Qll
modifiers, the number and
variety of instructions make their placement at the
end of this section desirable.
Read Check and Write Check Indicators
The Read Check and Write Check indicators (codes
06 and 07) are turned on if a parity error occurs in
the 1620 during input and output operations. Once
the Read or Write Check indicator is turned on it
,
is not turned O'ff by the reading or writing of subse-
quent correct characters; program interrogation or
manual reset is required to turn it off.
System Restart
The
CPU
will hang-up if the program addresses an
I/O
unit that is in a "not ready" cO'ndition. In this
ft
The Plotter (1627) and Paper Tape Reader and
Punch (1621) cannot be installed on the same system
except by special order.
Input/Output Instructions
event, the
CPU
should be stopped, the not ready con-
dition of the
I/O
unit corrected - Meter switch on,
Power-on switch on, correct placement of disk pack,
etc. - and the
CPU
restarted. (The master
1311's
Meter switch must be on to operate any slave 1311.)
Read Numerically (RN-36)
Description. Numeric information from an input
unit is transmitted serially to the P address and to
successively higher-numbered core storage locations.
TransmissiO'n continues until terminated by one of
the following conditions:
1. Sensing of the end-of-line character when
paper tape is being read. At this time a record
mark character is generated automatically by
the machine and placed in core storage follow-
ing the last character read from the tape.
2.
Depression of the Release key on the console
when the typewriter is used to enter informa-
tion. The Release key terminates typewriter
1/
a operations and puts the computer in man-
ual mode. A record mark character is not
generated automatically by the machine. If it
is desired to place a record mark in core
storage follOWing the last character entered,
the Record Mark key on the typewriter must
be pressed before pressing the Release key
on the console.
3.
Reading the 80th character from the Card
input buffer storage into core storage.
Each numeric character from an input device, along
with its flag bit (if any), is stored in a single, core
storage location. A parity check bit (C bit), if needed,
is furnished by the machine and stored in the same
location. All data that is replaced, including flag bits,
is destroyed.
The - (dash) and
J
through R characters from the
paper tape reader are entered into core storage as
numeric digits with flag bits. Numeric blanks from
the card reader are entered into core storage as C 8
and 4 bits and are punched out as blanks on a
writ~
Numerically operation. Actual blanks
(from un-
punched card columns) are entered intO' core storage
as plus zeros (C bits) and are punched out as zeros
on a Write Numerically operation. No other alpha-
betic or special characters (except the record mark)
are transmitted correctly to core storage when this
instruction is used.
39
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