Control Data 3100 Reference Manual page 169

Fractional binary numbers may be represented by using the symbols as coefficients
of ascending negative powers of the base.
2
-1
2
-2
2
-3
2
-4
2
-5 ...
Binary Point 1;2
!.4
Va
1116 1/32
The binary number 0.10 110 may be represented as:
1 x 2
-1
=
1 x
112
=
1/2 8/16
+
0 x 2
-2
=
0 x 1 14
=
0 0
+
1 x 2
-3
=
1 x 118
=
1/8 2/1 6
+1 x2
-4
=
1 x 1/16
=
1/16
=
Jil6
11/1610
OCTAL NUMBER SYSTEM
The octal number system uses eight discrete symbols, 0 through 7. With base eight the
positional value is:
8 5
32,768
8
4
4,096
8 3
512
8 2
64
The octal number' 5138 represents:
5
X
8 2
=
5 x 64
=
320
+1x8 1 =1x8
8
+3 x 8 0
=
3 x 1 __ 3_
33110
8
1
8 0
8 1
Fractional octal numbers may be represented by using the symbols as coefficients of as-
cending negative powers of the base.
8
-1
1/8
8
-2
1/64
The octal number 0.4520 represents:
8
-3
1/512
8
-4
1/4096
4x8 -1=4x1/8 =4/8 =256/512
+5x8 -2=5x1/64 =5/64
=
40/512
+2x8
-3
=2x1/512 =2/512
=
21512
298/512= 149/25610
B-2