Erick jon c. apa
HA3
1. Binary Number System
A set of eight
trigrams and a set of 64
hexagrams, analogous to the three-bit and six-bit binary numerals, were known in
ancient China through the
classic text I Ching. In the 11th century, scholar and philosopher
Shao Yong
developed a method for arranging the hexagrams which corresponds to the
sequence 0 to 63, as represented in binary, with yin as 0, yang as 1
and the
least significant bit on top. There is, however, no evidence that Shao understood binary computation. The ordering is also the
lexicographical order on
sextuples of elements chosen from a two-element set.
[7]
Similar sets of binary combinations have also been used in traditional
African divination systems such as
Ifá as well as in
medieval Western
geomancy. The base-2 system utilized in geomancy had long been widely applied in sub-Saharan Africa.
In 1605
Francis Bacon
discussed a system whereby letters of the alphabet could be reduced to
sequences of binary digits, which could then be encoded as scarcely
visible variations in the font in any random text.
[8]
Importantly for the general theory of binary encoding, he added that
this method could be used with any objects at all: "provided those
objects be capable of a twofold difference only; as by Bells, by
Trumpets, by Lights and Torches, by the report of Muskets, and any
instruments of like nature".
[8] (See
Bacon's cipher.)
The modern binary number system was studied by
Gottfried Leibniz in 1679. See his article:
Explication de l'Arithmétique Binaire[9](1703). Leibniz's system uses 0 and 1, like the modern binary numeral system. As a
Sinophile, Leibniz was aware of the
I Ching
and noted with fascination how its hexagrams correspond to the binary
numbers from 0 to 111111, and concluded that this mapping was evidence
of major Chinese accomplishments in the sort of philosophical
mathematics he admired.
[10]
In November 1937,
George Stibitz, then working at
Bell Labs, completed a relay-based computer he dubbed the "Model K" (for "
Kitchen", where he had assembled it), which calculated using binary addition.
[13]
Bell Labs thus authorized a full research programme in late 1938 with
Stibitz at the helm. Their Complex Number Computer, completed January 8,
1940, was able to calculate
complex numbers. In a demonstration to the
American Mathematical Society conference at
Dartmouth College on September 11, 1940, Stibitz was able to send the Complex Number Calculator remote commands over telephone lines by a
teletype.
It was the first computing machine ever used remotely over a phone
line. Some participants of the conference who witnessed the
demonstration were
John Von Neumann,
John Mauchly and
Norbert Wiener, who wrote about it in his memoirs.
[14][15][16]The Decimal Number System uses base 10. It includes
the digits from 0 through 9. The weighted values for each position
is as follows:
3. Octal Number System
The octal, or base 8, number system is a common system used with computers. Because of
its relationship with the binary system, it is useful in programming some types of
computers.
Look closely at the comparison of binary and octal number systems in table 1-3. You can
see that one octal digit is the equivalent value of three binary digits. The following
examples of the conversion of octal 2258 to binary and back again further
illustrate this comparison:
4. Hexadecimal Number System
A big problem with the binary system is verbosity. To
represent the value 202 requires eight binary digits.
The decimal version requires only three decimal digits
and, thus, represents numbers much more compactly than does the binary
numbering system. This fact was not lost on the engineers who designed
binary computer systems.
When dealing with large values, binary numbers quickly become too
unwieldy. The hexadecimal (base 16) numbering system solves these
problems. Hexadecimal numbers offer the two features:
- hex numbers are very compact
- it is easy to convert from hex to binary and binary to hex.
Since we'll often need to enter hexadecimal numbers
into the computer system, we'll need a different mechanism for
representing hexadecimal numbers since you cannot enter a subscript
to denote the radix of the associated value.
The Hexadecimal system is based on the binary system
using a Nibble or 4-bit boundary. In Assembly Language programming, most
assemblers require the first digit of a hexadecimal number to be 0, and
we place an H at the end of the number to denote the number base.
The Hexadecimal Number System:
- uses base 16
- includes only the digits 0 through 9 and the letters A, B, C, D, E,
and F
In the Hexadecimal number system, the hex values greater
than 9 carry the following decimal value: