RCA 301 Programmer's Reference Manual page 147

I Block Write Record Simultaneous (BWS)
General Description
This instruction writes from a designated HSM location to selected Data Record File cells. From one to ten
blocks of information may be transferred to the Data Record File with one instruction. A cell may contain a block
of one to 900 characters of information. In writing, a block is terminated by an End of Block (EB) Symbol or a
cell count of 900 characters. This instruction is performed in the Simultaneous Mode.
Format
Operation — I
N Selects the Data Record File Unit and the number of blocks to be written as indicated below:
Number of Blocks
fo be Written
First File
Second File
A Address — FISM address of first character to be written.
B Address — B must be zero (0).
0
Bj determines if record stays on turntable after operation.
B = odd — record returned to cage.
x
B = even — record stays on turntable and arm is placed at beginning of previously selected
x
band.
B specifies whether EB sensed or not.
2
B = 1 — block is terminated on counting of 900 characters.
2
B = 0 — count or EB recognition.
2
If EB sensed before 900 characters have been written, stop transfer to this cell. If
900 count reached before an EB sensed, stop transfer to this cell.
B addresses cells 1 through 10, with cell 1 specified by zero and cell 10 specified by 9.
3
Direction of Operation
Left to right.
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 Record
File and the arm is placed on the previously selected record on the turntable. As soon as the Normal Mode is
interruptable, the contents of the HSM location specified by the S Register are transferred to the Record File Buffer
and from the buffer to the specified cell. The contents of the S Register are increased by one and the contents of the
HSM location now addressed by the S Register are transferred in a like manner. When the end of a block is reached,
determined by T , M is decreased by one. When M is decreased to zero the operation terminates. The record does
2
not have to be returned to the cage to perform additional reads or writes to the same surface.
Final Register Contents
(S) = HSM address of location one to the right of the last character written.
t
(T), = (B)i
4
1 2 3
4
1 2 3
C D
A B
7 8
6
5
6 7 8
5
H
F G
E
10
9
0
9
I &
XI-13