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F
Sector Read Disc Normal (SRN)
General Description
This instruction reads from a selected sector of the Data Disc File to a designated HSM location. From one
to ten sectors of information may be transferred from the Data Disc File with one instruction. 160 characters are
transferred for each sect,qr designated.
10
4
Format
Pit/d
Operation —F
N
— Specifies additional number of sectors to be read as follows:
Additional Sectors
First File
Second File
A Address — Address of HSM location to receive the first character read from the Data Disc File. This address
must be an even number (left-hand end of a diad).
B Address — B
— designates first sector to be read:
0
First Sector to be Read
Will Not O verride Any DDF
Simultaneous Instruction
Will Ov erride Any DDF
Simultaneous Instruction
B
B
, B
1;
2
3
Direction of Operation
Left to right in HSM
Outline of Operation
A start signal is sent to the Data Disc File and the contents of the sector specified by the B address are
transferred to the Data Disc File Buffer and from the buffer to the HSM location, designated by the A Register.
Transfer is effected two characters at a time, with the contents of the A Register being incremented by two after
each pair of characters is transferred. When the additional number of sectors has been read, according to the N
character, the operation terminates.
If a character with faulty parity is read, an octal 57 (57
An indicator will also be set and will remain set until another read instruction is started.
If this instruction contains a bit in the B
Mode, the Simultaneous Instruction being performed will be terminated on the next transfer of data to or from the
file. The new instruction will then be executed in the normal manner.
XII-4
0
0
&
0
0
&
— specify the zone from which data is to be read:
Module
1
2
3
4
4
2
position and the selected Data Disc File is busy in the Simultaneous
0
1
2
3
4
5
2
4
5
1
3
B
C
D
E
A
u
:
f
2
4
1
3
5
4
1
2
5
3
D
A
B
C
E
Zone
000 to 107
108 to 215
216 to 323
324 to 431
Standard Location
STA (0212 - 0215 )
) will be stored in HSM in place of the faulty character.
s
6
7
8
9
6
7
8
9
F
G
H
I
8
6
7
9
8
6
7
9
I
F
G
H
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- The Rca 301 Code
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