2. Computer System
Computer is an electronic device, operating under the
control of instructions stored its own memory
That can accept data (input)
Process the data according to specified rules
(process)
Produce results (results)
Store the results for future use (storage)
3. Input -Any data and instructions entered into the memory of a
computer
- 4 types of input are text, graphics, audio and video
Input device -Any hardware component that allows users to enter data
and instructions into a computer
-Examples: keyboard, mouse, joystick, scanner
Processor / -An electronic component on a computer’s motherboard
CPU / that interprets and carries out the basic instruction that
Microprocessor operate the computer
-Examples: Intel Pentium IV, AMD Athlon
Output - Data that has been processed into a useful form, called
information
Output device -Any hardware component that present information
(processed data) to one or more people
-Examples: speaker, monitor, LCD projector, printer
Storage -A location in which data, instructions and information are
saved for future used
-Examples: CD ROM, diskette, hard disk
4. Block Diagram of the Information
Processing Cycle
INPUT PROCESS OUTPUT
STORAGE
5. The processing unit controls all activities within the
system.
For every instruction, the control unit repeats a set
of four basic operations called machine cycle
(fetch, decode, execute and store)
7. Functions of CPU
Fetch a program instructions or data item from memory
Decode the program instructions into signals that
computer can execute
Execute the instructions
Store the result of instructions to the memory
Interprets and carries out basic instructions that operate
a computer
Control unit directs and coordinates operations in
computer
Arithmetic logic unit (ALU) performs arithmetic,
comparison and logical operations
8. Data Representation
Bit
o A bit (short for binary digit) is the smallest unit of
data the computer can process
o The binary system is a number system that has two
unique digits, 0 and 1, called bits
o They correspond to the states of on and off, true
and false or yes and no
9. Byte
o Byte is a unit of information built from bits
o When 8 bits are grouped together as a unit, they
form a byte
o A byte provides enough different combinations of
0s and 1s represent 256 individual characters
10. Character
o One byte is equals to 8 bits
o One byte represents a single character such as the number,
letter or symbol
o Example is capital F represented by binary code
01000110 that can be understood by the computer system
o There are 3 character codes to represent characters which
are ASCII, EBCDIC and Unicode
o The 256 character capability of ASCII and EBCDIC is too
small to handle the characters that are used by other
languages such Arabic, Japanese and Chinese
8 bits = 1 byte
11. What is ASCII??
ASCII (pronounce as-key) is an acronym for
American Standard code for Information
Interchange
Used in most computers to represent letters,
numbers and other characters
12. Function of ASCII Code
ASCII was established to achieve capability
between various types of data processing
equipment making it possible for components to
communicate with each other successfully
ASCII enables to manufacturers to produce
components that are assured to operate correctly
in a computer
14. Clock Speed Measurement
Every microprocessor contains a system clock
The clock speed unit is measured in hertz
A hertz is on cycle per second
1 Hz = 1 GHz =
1 MHz =