RCA 301 Programmer's Reference Manual page 27

Addressing
Addressing is a function of the retrieval unit, which contains the required registers as follows:
A full register for selection.
A full register for preselection.
A magazine address register used to return a card to its associated magazine.
These registers permit overlapping of the selection, preselection, and return of cards.
INSTRUCTIONS
The instructions utilized to program the Random Access device include:
These instructions are described on the following pages under the headings:
Select, Reading, Writing, and input/output sense.
The read/write head assembly, which contains eight pairs of heads (one Read, one Write head for each pair),
can be moved to one of sixteen positions. Once positioned, the head assembly is capable of reading or writing to
one of four bands, each band containing four blocks.
Card Select
The Card Select time (275 ms. nominal) 260 ms. minimum; 290 ms. maximum; is the time required to select
a specific card from a magazine and place it into position to be extracted onto the raceway. If at this point of time
the card can be placed on the capstan, it will be immediately extracted. Approximately 75 ms. nominal (67-82 ms.)
is required to clear a card from the Preselect position through the pinch rollers that place it on the raceway. At this
point, another card select is permissible.
Timings
(all times are in milliseconds and are nominal)
Position*
OA
0B/1A
1B/2A
2B/3A
-
00
3B/4A
00
4B/5A
CO
5B/6A
6B/7A
7B
8A
8B/9A
9B/10A
10B/11A
cs
t
11B/12A
00
00 00
12B/13A
T T
CO CO
13B/14A
14B/15A
15B
* where A = 1st half of magazine and B = 2nd half of magazine
Select (SEL)
Read Normal (RFN)
Read Simultaneous (RFS)
Write Normal (TWN)
Write Simultaneous (TWS)
Input/Output Sense (IOS)
Card Select Card Feed
i
i 136
145
156
172
185
198
211
225
235
<r>
r>
c
*
275
288
302
313
324
335
346
357
1
r
368
Card Return Reload
{
170 I
182
196
209
222
235
248
262
275
o
11 rj
327
341
355
369
383
397
411
425
1 r
441
11-11