CHAPTER 2_INTRO TO COMPUTER SYSTEM.pptx

LOGO
CHAPTER 2: INTRODUCTION
TO COMPUTER SYSTEM

COMPANY LOGO
www.themegallery.com
LEARNING OBJECTIVES
Computer System
1
2
3
The System Unit
4 Input and Output
The CPU and Primary Storage
5 Computer Software
6 Programming Language

COMPANY LOGO
WHAT IS AN COMPUTER SYSTEM?
 Computer system consists of (refer Figure 1.0) :
a. System Unit
b. storage
c. Input devices
d. Output devices
e. Communications devices.

COMPANY LOGO
FIGURE 1.0: HARDWARE COMPONENT OF
COMPUTER SYSTEMS
Communication
Devices
Secondary Storage
- Magnetic disk
Central Processing
Unit (CPU)
Primary Storage
Input Devices
- Keyboard
Output Devices
- Printers
Buses

COMPANY LOGO
THE SYSTEM UNIT
 What are common components inside the system unit?
a. Processor
b. Memory
c. Adapter cards
i. Sound card
ii. Video card
d. Port
e. Drive bays
f. Power supply
power supply
ports
drive bays
processor
memory
sound card
video card

COMPANY LOGO
THE SYSTEM UNIT
 What is motherboard?
 Main circuit board in
system unit.
 Contains adapter cards,
processor chips, and
memory chips.
 Also called system board.

COMPANY LOGO
THE SYSTEM UNIT
 The CPU
 Manipulates raw data into more useful form and controls the
other parts of the computer system.
 Primary storage / RAM
 Temporarily stores data and program instructions during
processing.
 Secondary storage
 Devices store data and programs when they are not being used
in processing. Mainly Hard disk HDD dan Solid State Drive
(SSD)

COMPANY LOGO
THE SYSTEM UNIT
 Input devices
 Convert data and instructions into electronic form for input into
the computer.
 Output devices
 Convert electronic data produced by the computer system and
display them in a form that people can understand (information).
 Communication devices
 Provide connections between the computer and communications
networks.

COMPANY LOGO
THE SYSTEM UNIT
 Buses
 Circuitry paths for transmitting data and signals among the parts
of the computer system.

COMPANY LOGO
HOW COMPUTERS REPRESENT DATA ?
 All symbols, pictures or words must be reduced to a string of
binary digits.
 A binary digit is called a bit and represents either a 0 or a 1.
 These are the only digits in the binary or base 2, number
system used by computers.
 A string of eight bits used to store one number or character in a
computer system is called a byte (refer Figure 2.0).

COMPANY LOGO
Figure 2.0: HOW COMPUTER REPRESENT
DATA
One byte for character A 01000001
The computer representation in ASCII for the name
Alice is
01000001 A
01001100 L
01001001 I
01000011 C
01000101 E

COMPANY LOGO
HOW COMPUTER REPRESENT DATA
 To represent the numbers 0 through 9 and the letters a through
z and A through Z, computer designers have created coding
systems consisting of several hundred standard codes.
 In one code, for instance, the binary number 01000001 stands
for the letter A.

COMPANY LOGO
 Two common coding systems;
a. Extended Binary Coded Decimal Interchange Code
(EBCDIC)
b. American Standard Code for Information Interchange
(ASCII).
 EBCDIC represents every number, alphabetic character, or
special character with eight bits, used primarily in IBM and
other mainframe computers.
 ASCII was originally designed as a seven-bit code, but most
computers use eight-bit versions.

COMPANY LOGO
 ASCII is used in data transmission, PCs and some larger
computers.
 The computers store a picture by creating a grid overlay of the
picture.
 Each single point in this grid, or matrix is called a pixel (picture
element) and consists of a number of bits.

COMPANY LOGO
DATA REPRESENTATION
 How is a letter converted to binary form and back?
Step 1.
The user presses
the capital letter D
(shift+D key) on
the keyboard.
Step 2.
An electronic signal for the
capital letter D is sent to the
system unit.
Step 3.
The signal for the capital letter D
is converted to its ASCII binary
code (01000100) and is stored in
memory for processing.
Step 4.
After processing, the binary
code for the capital letter D is
converted to an image, and
displayed on the output device.

COMPANY LOGO
THE CPU AND PRIMARY STORAGE
 The CPU is the part of the computer system where the
manipulation of symbols, numbers, and letters occurs, and it
controls the other parts of the computer system.
The CPU

COMPANY LOGO
PROCESSOR
 What is the Central Processing Unit (CPU)?
 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
 Also called as processor

COMPANY LOGO
PROCESSOR
Processor
Control
Unit
Arithmetic
Logic Unit (ALU)
Input
Devices
Output
Devices
Memory
Data Information
Instructions
Data
Information
Instructions
Data
Information
Storage
Devices

COMPANY LOGO
PROCESSOR
 What is a machine cycle?
 Four operations of CPU comprise of machine cycle.
Processor
Control Unit
Memory
ALU
Step 1. Fetch
Obtain program instruction
or data item from memory
Step 2.
Decode
Translate
instruction into
commands
Step 4. Store
Write result to memory
Step 3. Execute
Carry out command

COMPANY LOGO
Control Bus
Address Bus
Data Bus
Central Processing Unit (CPU)
Arithmetic Logic Unit (ALU)
22 + 11 = 33
Control Unit
Primary Storage
I
8
# U

COMPANY LOGO
 Three kinds of busses linked between the CPU, primary storage
and the other devices in the computer system;
 Data bus
• Pass information in bi-directional.
 Address bus
• Transmits signals for locating a given address in primary
storage, indicating where data should be placed.
 Control bus
• Transmits signal specifying whether to read or write data to
or from primary storage address, input device or output
device.

COMPANY LOGO
 The characteristics of the CPU and primary storage are very
important in determining a computer’s speed and capabilities.

COMPANY LOGO
THE ARITHMETIC-LOGIC UNIT AND
CONTROL UNIT
 An arithmetic logic unit (ALU) and control unit is one of the
core components of all central processing units.
 The ALU performs the computer’s principal logical and
arithmetic operations.
 It adds, subtracts, multiples, and divides, determining whether
a number is positive, negative, or zero.
 ALU must be able to determine when one quantity is greater
than or less than another and when two quantities are equal.

COMPANY LOGO
THE ARITHMETIC-LOGIC UNIT AND
CONTROL UNIT
 The control unit coordinates and controls the other parts of the
computer system.
 It reads a stored program, one instruction at a time and directs
other components of the computer system to perform the
program’s required tasks.

COMPANY LOGO
PROCESSOR
 Which processor should you select?
 The faster the processor, the more expensive the computer.
Celeron
Itanium or Xeon
Pentium family
1.3 GHz and up
3.0 GHz and up
2.4 GHz to 3.0 GHz
Up to 2.4 GHz
2.2 GHz and up
Intel Processor Desired Clock Speed

COMPANY LOGO
PRIMARY STORAGE
 Primary storage is a category of computer storage, often called
main memory.
 Has three functions:
 Stores all or part of the program that is being executed.
 Stores the operating system programs that manage the
operation of the computer.
 Holds data that the program is using.
 Data and program are placed in primary storage before
processing, between processing steps and after processing
has ended prior to being returned to secondary storage or
released as output.

COMPANY LOGO
MEMORY
 How is memory measured?
 By number of bytes available for storage
TERM ABBREVIATION APPROXIMATE SIZE
Kilobyte KB or K 1 thousand bytes
Megabyte MB 1 million bytes
Gigabyte GB 1 billion bytes
Terabyte TB 1 trillion bytes

COMPANY LOGO
MEMORY
 Modern primary storage devices include:
 Random access memory (RAM)
• Is used for short-term storage of data or program
instructions. RAM is volatile. Its contents will be
lost when the computer’s electric supply is disrupted
by a power outage or when the computer turned off.
 Read-only memory (ROM)
• Can only be read from. It cannot be written to.
ROM chips come from the manufacturer with
programs already burned in, or stored. ROM
is used in general-purpose computers to
store important or frequently used programs,
such as computing routine for calculating the
square roots of numbers.

COMPANY LOGO
MEMORY
 How do program instructions transfer in and out of RAM?
Step 1. When you start the computer, certain
operating system files are loaded into RAM from
the hard disk. The operating system displays the
user interface on the screen.
Step 2. When you start a Web browser, the
program’s instructions are loaded into RAM from
the hard disk. The Web browser window is
displayed on the screen.
Step 3. When you start a word processing
program, the program’s instructions are loaded
into RAM from the hard disk. The word
processing program, along with the Web Browser
and certain operating system instructions are in
RAM. The word processing program window is
displayed on the screen.
Step 4. When you quit a program, such as the
Web browser, its program instructions are
removed from RAM. The Web browser is no
longer displayed on the screen.
Web browser
window is no longer
displayed on
desktop
Operating system
interface
Web browser
window
Word processing
program window
RAM
RAM
Web browser program
instructions are
removed from RAM
Operating system
instructions
Web browser
instructions
Word processing
program instructions

COMPANY LOGO
MEMORY
 What are two basic types of RAM chips?
 Static RAM (SRAM)
• Faster and more reliable than DRAM chips
• Do not have to be re-energized as often as DRAM
 Dynamic RAM (DRAM)
• Most common type
• Must be re-energized constantly
 Newer Type: Magnetoresistive RAM (MRAM)

COMPANY LOGO
MEMORY
 What is read-only memory (ROM)?
Three types:
Firmware
Manufactured with
permanently written
data, instructions,
or information
EPROM
(Electrically
Erasable Programmable
Read-Only Memory)
Type of PROM
containing microcode
programmer
can erase
PROM
(Programmable
Read-Only
Memory)
Blank ROM
chip onto which
a programmer
can write permanently
Memory chips that store
permanent data
and instructions
Nonvolatile memory, it is not
lost when computer’s
power is turned off

COMPANY LOGO
STORAGE
 What is storage?
 Storage medium is physical material used for storage.
 Holds data, instructions, and information for future use.
 Also called secondary storage. 1.44 mb

COMPANY LOGO
STORAGE
 How does volatility compare?
 Storage medium is non-volatile – contents retained when
power is off.
 Memory is volatile – holds data and instructions temporarily.
Memory
(most RAM)
(chips on motherboard)
Screen Display
Storage Medium
(floppy disks, Zip disks,
hard disks, CDs)
Contents
retained
Contents
available to
user
Display
disappears
Data and
instructions
available to user
Display
appears
Data and
instructions erased
ON OFF
Nonvolatile
Volatile

COMPANY LOGO
WHAT IS INPUT?
 Data or instructions entered into memory of computer.
 Input device is any hardware component that allows users to
enter data and instructions.

COMPANY LOGO
WHAT IS OUTPUT?
 Data that has been processed into a useful form.
 Output device is any hardware component that can convey
information to user.

COMPANY LOGO
COMPUTER SOFTWARE
 Application Software /apps
 Refers to programs that are developed to solve some specific
problems.
 There are two types of application software:
a. Application program to solve special classes of
problems.
b. Application programs that you can write to solve your
own problems.
 Examples of application software:
a. Word processing – ms word / lotus/ wps
b. Database programs – ms access (database)
c. Spreadsheets – ms excel
d. Presentation programs –ms powerpoint

COMPANY LOGO
COMPUTER SOFTWARE
 System Software
 Refers to programs that make the computer usable and
accessible to the developers and programmers of applications
software.
 Examples of system software:
a. Operating systems – Microsoft windows
b. Language translator
c. Linker
d. Loader
e. Preprocessors

COMPANY LOGO
PROGRAMMING LANGUAGES
 Programming Language is an agreed upon format of symbols
that allow a programmer to instruct a computer to perform
certain predefined tasks. ( C++, java, php,visual basic)
 Apps -> My sejahtera (programmer ) – program interface,
function
 Apps -> Microsoft word (programmer company Microsoft)
Apps - > mobile legend, candy crush,
Antivirus – avg, kapersky
 Provide features to support the data processing activities,
which include declaring variables, evaluating numeric
expressions, assigning values to variables, reading and writing
data to devices, looping and making decisions.

COMPANY LOGO
PROGRAMMING LANGUAGES
 There are three types of programming languages;
a. Machine language
• Is the natural language of a computer.
• Does not need to translate and is ready for immediate
execution.
• Machine language instruction is a binary string of 0s and 1s.
– 010 1 1000 0001 0000 1100 0000 0001 0000
• Are machine-dependent; each computer type has its own
machine language.
• Programs written in machine languages are not portable
because programs written in for one type of computer cannot
be run on another type.

COMPANY LOGO
b. Assembly Languages
• Consists of English-like abbreviations.
• Easier to understand.
– L 1, GROSSPAY
– S 1, TAX
– ST 1, NETPAY
• Program written in assembly languages cannot be directly
processed by a computer.
• Must use language translators, called assemblers, to convert
them to machine code.
• Disadvantages:
– In general, each assembly language instruction
corresponds to one machine language instruction.
Therefore, the programs written in them are lengthy.
• Because of variations in assembly languages, programs
written using them are not portable.

COMPANY LOGO
c. High-Level languages
• Instructions are quite English-like, and a single instruction can be
written to correspond to many operations at the machine level.
• For example, the assembly language program can be written in
high-level languages as follows:
• Netpay = gross pay – tax
• Are easier to learn than machine or assembly languages.
• Have to be converted to machine languages before they can be
executed using compilers, system software that translates a
source program into an almost executable object program.

CHAPTER 2_INTRO TO COMPUTER SYSTEM.pptx

More Related Content

Similar to CHAPTER 2_INTRO TO COMPUTER SYSTEM.pptx

Recently uploaded

CHAPTER 2_INTRO TO COMPUTER SYSTEM.pptx