D
Band Select Normal (BSN)
General Description
This instruction initiates a search of a designated Data Record File for the record containing a specified band,
places the record on the turntable and advances the read/write arm to the "ready" position. Once this instruction
is initiated (staticizing and establishing a control counter), the data record and band are selected independent of
computer operation.
A Band Select Normal instruction must be issued prior to a Block Read (or Write) Record Normal (or Simul
taneous) instruction (BRN, BRS, BWN, BWS). These instructions may be used to address one of two Data Record
Files controlled through a Data Record File Control.
Format
Operation —D
N
— Selects the Data Record File Unit and Band as indicated below:
1 st File
2nd File
Effect
0
&
The record on the turntable, if any, will be returned to the cage. The
desired record is then placed on the turntable and the indicated band
selected.
1
A
The band selected is one of the two on the upside of the record on the
turntable. If the B address is even, the first band will be selected; if odd,
the second band will be selected.
A Address — Must be zeros (0000).
B Address — B
0
must be zero (0); B
1;
B
2
, B
3
designate band (000 to 511).
Outline of Operation
Band addresses are numbered from 000 through 511 and are specified by the last three digits of the B address.
The contents of the N Register designate the proper Data Record File and specify whether the record on the turn
table, if any, is to be returned to the cage or not.
Final Register Contents
(A)
f
= (A),
(B)t = (B),
Timing
A. Computer time to initiate selection (staticizing and establishing address counter) in microseconds: 21 (B,)
+ 14 (B
2
) + 42.
B. Select data record from storage wheel:
Note. Since the 128 position data record storage wheel rotates in either direction, the maximum data record
position from the selection point is 64.
XI-3
Summary of Contents for 301
Page 6: ...HRSfOTPflf I I I I ...
Page 16: ......
Page 34: ......
Page 43: ......
Page 44: ......
Page 47: ......
Page 48: ......
Page 61: ......
Page 62: ......
Page 74: ......
Page 75: ......
Page 76: ...j I j I I ...
Page 86: ......
Page 87: ......
Page 88: ......
Page 108: ......
Page 109: ......
Page 110: ......
Page 126: ......
Page 127: ......
Page 128: ...X ry V ...
Page 134: ......
Page 135: ...INPUT OUTPUT INSTRUCTIONS DATA RECORD FILE INPUT OUTPUT INSTRUCTIONS DATA RECORD FILE XI l ...
Page 136: ......
Page 154: ......
Page 156: ......
Page 175: ......
Page 176: ......
Page 180: ...WWH H i i w m H H J V fi t y v if i Hk I ...
Page 182: ......
Page 195: ......
Page 234: ......