RCA 301 Programmer's Reference Manual page 117

7 Tape Read Reverse Simultaneous (RRS)
General Description
This instruction transfers a series of consecutive characters from magnetic tape or punched paper tape into
the HSM. Transfer from tape begins with the first character following a gap and ends when the next gap is sensed
or the specified HSM area is filled. Though the tape moves in reverse, the characters will be placed in their proper
relative position within HSM. This instruction operates in the Simultaneous Mode.
Format
Operation — 7
N — Identification character of Tape Station or Paper Tape Reader. (See Appendix G.)
A Address — Address of HSM location to receive the first character read from tape.
B Address — Address of HSM location to receive the last character read from tape.
Direction of Operation
Right to left.
Direction of Tape Motion
Magnetic tape moves in a reverse direction. Paper tape will move in the forward direction but characters read
from paper tape are placed in memory from right to left.
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, and T Registers
respectively, and this instruction is executed in the Simultaneous Mode. This instruction sends a start signal to the
input unit specified by the contents of the M Register. After a gap is passed on magnetic tape, the first character
is placed in the input buffer, and this instruction operates in the following cycle:
The character in the input buffer is transferred to the HSM location specified by the S Register. The contents
of the S Register are decremented by one. If a gap is passed in sequence, the instruction terminates. If the comparison
proves equal and a gap is not passed, the instruction terminates, and tape movement continues to gap. If the
comparison proved not equal and a gap is not passed, the cycle is repeated.
If an EF or ED alone is read from magnetic tape, the EF/ED Simultaneous Indicator is set. The EF/ED
Simultaneous Indicator is not set when reading from paper tape. If SMDI is set, the EF/ED Normal Indicator will
be set.
If ETW is passed the ETW flip-flop is reset.
Final Register Contents
(S) = Address of location one to the left of the last character read.
t
(T) = (B)i
t
Timing
Hi-Data tapes, Model 381, are read at the rate of 10 KC.
Hi-Data tapes, Model 382, are read at the rate of 30 KC.
Paper tape is read at the rate of up to 1000 characters per second.
The tape station attached to the Tape Adapter or Dual Tape Channel is read at the rate of 33.3 KC if it is a
Model 581 Tape Station or 66.7 KC if it is a Model 582 Tape Station.
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