MAGICAL LANGUAGE
Binary number system: A numerical system wherein
each digit stands for a power of two. The binary system
uses only two symbols, 0 and 1, to represent values.
In the decimal system, commonly used in most
countries, each digit represents a value
of 10. For example, the number 103 would break down
as follows:
1 x 100 = 100
0 x 10 = 0
3 x 1 = 3
103 = 103
In the binary system, each digit position represents a
value of 2. Because computers use the binary system,
powers of 2 play an important role. This is why
everything in computers seems to come in 8s (2 to the
3rd power), 64s (2 to the 6th power), 128s (2
to the 7th power), and 256s (2 to the 8th power).
Therefore, in the binary system, the number 103 would
break down as follows:
1 x 64 = 64
1 x 32 = 32
0 x 16 = 0
0 x 8 = 0
1 x 4 = 4
1 x 2 = 2
1 x 1 = 1
1100111 = 103
The values in a binary system -- the 0s and 1s -- are
called ‘binary digits’ or bits.
Binary digit (bit): A digit within the binary number
system. A bit is the smallest unit of information held in
a computer.
The computer’s electronic circuits have only two states,
on or off, and therefore can only understand 0s and 1s,
which may represent such opposites as on or off, yes
or no, or up or down. This is why all computers use the
binary system. In order to make the bits useful, they
are combined into ‘bytes’ of information.
Byte: A
combination of bits that represent one
character. A byte is usually composed of 8 bits
Computer programmers have developed codes for
various bytes of information, so that they may be read
by different computer programs. For example, one
code might define the letter A as ‘11000001’ and the
letter B as 11000010’.
The number 6 might be defined as ‘11110110’ and the
number 8 as ‘11111000’. When the person entering
data strikes the A key on the keyboard, the computer
registers it as ‘11000001’. When he or she enters the
B, the computer reads it as ‘11000010’. Similarly, the
number 6 is understood by the computer as ‘11110110’
and the number 8 as ‘1111100’. In this way, the
computer can store words and numbers as binary digits
and then retrieve them and convert them back into
words or numbers as required.
As discussed earlier, this work of manipulating, storing
and processing the data takes place in the Central
Processing Unit, the computer’s main memory. The
CPU consists of an arithmetic and logic unit, or ALU, a
control unit, and a set of registers.
The arithmetic and logic unit is the portion of the
CPU where arithmetic and logical operations take place.
The control unit is the part of the CPU that
supervises the general operations of the computer.
The registers are devices that hold data inside the
computer’s memory long enough to execute a
particular function, such as indexing, calculating,
sorting or otherwise manipulating data. They are the
CPU’s own internal memory.
Data travels from one part of the computer to another
through a kind of path known as a bus.
Bus: The
channel or path that lets the parts of a
computer communicate with each other.
Similar to a school bus for school children, a computer
data bus picks up a load of data from one of the
components on the main computer board and then
transfers the data to another component on the main
computer board. The main circuit board of a
microcomputer is also known as the motherboard. The
motherboard is the principal board that has connectors
for attaching devices to the bus. Typically, it contains
the CPU, memory and basic controllers for the system.
The data bus is really a series of electrical circuits that
connect the various electrical elements on the main
board.
The data are input into the computer and processed in
the CPU. They travel along the bus to be stored in the
computer’s memory. The amount of memory available
is described in bytes of information, referring to the
combination of bits representing characters. The higher
the number of bytes the more memory the computer
has.
Today’s computers hold ‘megabytes’ or even
‘gigabytes’ of data. A megabyte is a unit of one million
bytes; a gigabyte is one billion bytes, and a terabyte is
one trillion bytes. If a computer has a memory of 64
megabytes, then it can hold 64 million bytes of
information.
Data can be stored so that it is readable again only
using the software with which it was created, or it can
be stored in other formats, so that it may be
transferred or used by other software programs. There
is a standard character code used to store data so
that it may be used by other software programs; this
code is called ASCII or American Standard Code for
Information Interchange. The ASCII code assigns a
specific pattern of bits to each character, as described
above. Another code that may be found, especially in
IBM-brand mainframe computers, is EBCDIC, or
Extended Binary Coded Decimal Interchange Code. The
important point to remember about these codes is that
their main value is to store information so that it is
readable by other computers. By using ASCII or
EBCDIC, it is possible for people to retrieve and use
someone else’s data using a different type of hardware
or software. The main disadvantage of using ASCII or
EBCDIC is that the formatting or other special
qualities of
computerised information may be lost.
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