mt
0 Card Read Normal (CRN)
General Description
This instruction reads information from punched cards in the Read Unit of the Card Reader-Punch into the HSM
using the Normal Mode.
Format
Operation — 0 (Zero)
Symbol
Result
K
1
Binary read mode specified
Translate read mode specified
A Address — Address of HSM location to receive the first character read from punched cards.
B Address — Must be zeros (0000).
Direction of Operation
Left to right.
Outline of Operation
This instruction directs the Card Reader Unit to place a card in the read station and operates on successive
characters in the following cycle:
When the translate read mode has been specified (N = 1) the character in column one of the punched card is
automatically translated from RCA Card Code to RCA 301 code and is placed in HSM in the location specified by
the A Register. The following 79 characters are placed in successive locations in HSM. The final character (column
80) is located at (A+ + 79.
When the binary read mode has been specified (N = K) each card column is split into two groups of six bits
each, a parity bit is generated and added to each group, and the resultant two characters are transferred into HSM.
The character represented by rows 9 through 4 in column 1 (row 9 — 2
5
, row 4 = 2°) is read into HSM at the
location specified by the A Register. Successive characters representing rows 9 through 4 are also read into memory
with column 80 being placed at (A)
(
+ 79. The character represented by column 1, rows 3 through Y (row 3 = 2
5
,
row Y = 2°) is read into HSM at (A)j + 80. Successive characters representing rows 3 through Y are likewise read
into HSM with column 80 being placed at (A)j +159. The final A Register setting is (A), + 160.
A card read instruction must be staticized for each card read. In order to maintain an 800 card per minute rate,
successive Card Read Instructions must be staticized before 75 milliseconds have elapsed. The 75 milliseconds card
cycle is comprised of 21 milliseconds card feed access time, 44 milliseconds card read time, and 10 milliseconds time
free for compute. When the read release option is exercised (via the Input/Output Control Instruction), an additional
21 milliseconds of compute time is made available.
Final Register Contents
(A), = One location to the right of the last character read into HSM.
(B)
(
= (A)j when N = 1 (Translate Read Mode).
(B)t = (A)j + 80 when N = K (Binary Read Mode).
VIII-7
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