RCA 301 Programmer's Reference Manual page 160

G Sector Read Disc Simultaneous (SRS)
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 sector designated. However, this instruction may be terminated by any other Data Disc File
instruction to the same file when the terminating instruction has the proper B
Format
Operation —G
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 Ov erride Any DDF
Simultaneous Instruction
Will Ov erride Any DDF
Simultaneous Instruction
Bu B , B
2 3
Direction of Operation
Left to right in HSM.
Outline of Operation
Initially this instruction is staticized in the Normal Mode. If the Simultaneous Mode is free and the SMDI button
is not on, the contents of the NOR, N, A and B Registers are transferred to the SOR, M, S, T Registers respectively,
and this instruction is executed in the Simultaneous Mode. A start signal is sent to the Data Disc File. The contents
of the sector, as specified by the T Register are transferred to the Data Disc File Buffer, and when the Normal Mode
is interruptable, from the buffer to the HSM location designated by the S Register. Transfer is accomplished two
characters at a time, with the contents of the S Register being increased 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.
The operation may also be terminated by another Data Disc File instruction to the same file when the B
character of the overriding instruction ranges from
XII-6
0
0
&
0
0
&
— specify zone from which data is to be read:
Module
1
2
3
4
to "I" as specified above.
MT used
override character.
0
2 4
1 3 5
4
1 2 3 5
D E
A B C
1 2 4 5
3
2 4
1 3 5
D
A B C E
Zone
000 to 107
108 to 215
216 to 323
324 to 431
6 7 8
9
8
6 7 9
G H I
F
6 8
7 9
6 7 8 9
H I
F G
0