User`s manual

~ 08107 ~
16 BIT DATA WORD
HIGH BYTE LOW BYTE
00000 1 000000
r---------~------~
000003 000002
757777
760001
--
----
-
--
--
757776
760000
*777777 777776
1
USER ADDRESS SPACE
AVAILABLE USING 18
ADDRESS BITS ON
PDP-11 PROCESSOR
J
WITH MEMORY
MANAGEMENT OPTION.
INCLUDES 248K(253,952)
BYTES OR 124K(126,976)
WORDS.
HIGHEST
8K (8192)
BYTES OR 4K(4096)
WORDS RESERVED FOR
DEVICE REGISTER
ADDRESSES.
LLAST ADDRESS IS BYTE NUMBER 262.143,0
* MAXIMUM SIZE WITH 18 ADDRESS BITS IS 256K(262,144) BYTES OR 128K(131,072)WORDS.
Figure A-I Memory Organization for Maximum
Size
Using 18 Address Bits
Memory Size Memory capacities of 56K bytes (28K words) or
under do not have the problem of interference with
the reserved area, because designations less than
160000 do not have a binary I in bit A 13. No address-
es
are converted and there is no possibility of physical
memory locations interferring with the reserved
space.
K-Words K-Bytes
PDP-II core memories are available in 4K, 8K, or
16K increments. The highest location of various size
core memories are shown.
A-2
4
8
12
16
20
24
28
8
16
24
32
40
48
56
11-1690
Highest Location
(Octal)
017777
037777
057777
077777
117777
137777
157777