Programming instructions

MEMORY
The memory contains stored information for processing, and the instruc-
tions of the program being run. Memory capacities of from 1,024 to 32,768
words are available in PDP-4. Standard models PDP-4A and PDP-4B come
with 1024-word and 4096-word memories, respectively. The two models
are identical in all other respects. The smaller memory has a 32 by 32 by
18 core array, the larger a 64 by 64 by 18 core array. A Memory Module
Type 17, containing a 64 by 64 by 18 core array may be added to PDP-4B
to give it an 8192-word capacity. With the addition of the Magnetic Core
Memory Extension Control Type 16, memory modules may be added to
build a memory of 32,768 words. Further increase in storage capacity can
be gained by adding the Magnetic Drum System Type 24, available in
three capacities: 16,384, 32,768, and 65,536 words.
OPERATOR CONSOLE
The Operator Console contains all the switches and controls necessary to
run the machine, and lights which indicate the current status of the In-
ternal Processor. The functions of the lights and controls are described
in the following tables.
Figure 4 - Operator Console
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