Transcript
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COMPUTER SYSTEM
• Combination of components designed to process data and store files
• Consists of four major hardware components input devices, output devices, processor and storage devices
• Needs hardware, software and a user to fully function
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*input devices*processor*output devices*storage devices
COMPUTER HARDWARE
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Input devices
Output devices
hardware
software
Computer system
COMPUTER HARDWARE COMPUTER HARDWARE BLOCK DIAGRAMBLOCK DIAGRAM
Input devices
processor
Storage devices
output devices
An Input device feeds raw data to the processor. A processor processes raw data and turns it into useful information. A storage device keeps or stores both process and unprocessed data for later usage. An output device shows or display the processed data
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Any questions so far?
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Human uses the brain to think, make decisions and
process information. A computer has a brain too,
and the brain of a computer is the processor or the central processing unit (CPU) that processes
information
THE CENTRAL PROCESSING UNIT
All processing activities are done in the CPU
It utilizes the computer memory to execute instructions from the application software and accomplish a task
The processor must be connected to input devices, output devices and storage devices to carry out the tasks
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THE INFORMATION PROCESSING CYCLE
Input processor
Storage
output
User will input the data to be processed by the
processor.The storage holds
databases, files and programs. The output of the processed data will
be displayed by the output devices present as useful information products for the user
The Information Processing Cycle
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Draw the computer hardware block diagram
and the information processing cycle. Explain
briefly each diagram
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Information processing cycle
Any data or instructions that we enter into the computer system for processing
Input
A location which data, instruction and information are held for future use
Storage
Data that has been processed into a useful form information
Output
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Machine cycle that consist four basic operations, that’s are fetching, decoding, executing and storing
Process
Fetching
DecodingStoring
Executing
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FetchingThe process of obtaining a program instructions or data item from memory
Decoding The process of translating a program instruction into signals that the computer can execute
StoringThe process of writing the result to the storage or memory
Executing The process of implementing the instructions in a program.
process
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Any questions?
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DATA REPRESENTATI
ON
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Computers recognize only two discrete states on & offThese states can be represented by two digits 0 & 1Each 0 or 1 is called a bit in the binary system.
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BINARY DIGIT
The smallest unit of data a computer can process The binary system has a base of 2 with the two digits (0 and 1) Combinations of 0s and 1s represent larger numbers
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BYTE
• Unit of information built from bits
• 1 byte = 8 bits• One byte represents a single character (3, B or #)
• Unit of information built from bits
• 1 byte = 8 bits• One byte represents a single character (3, B or #)
CHARACTER
• One byte represents one character such as A, 7, 9 and +
• F = 01000110 (binary code)
• One byte represents one character such as A, 7, 9 and +
• F = 01000110 (binary code)
00111001 = 900101011 = +
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æThree character codes to represent characters
æASCII, EBCDIC, Unicode
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* ASCII (American Standard Code for Information Interchange)* Proposed by ASA (American Standard Association)
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To achieve compatibility between various types of data processing equipment making it possible for the components to communicate with each other successfully
Enables manufacturers to produce components that are assured to operate correctly in a computer
Enables human to interact with a computer
Enables users to purchase components that are compatible with their computer configurations
FUNCTIONS OF ASCII
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HOW ASCII WORKS IN A COMPUTER SYSTEM?
When you press a key, for example the letter D on your keyboard, the electronic signal is sent to the CPU for the computer to process and store in memory. Every character is converted to its corresponding binary form. The computer the processes the letter as a byte, which actually a series of on and off of electrical states. When the computer is finished processing the byte, the software installed in the system convert the byte back which is then displayed in the screen. Example, the letter D is converted to 01000100
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DATA DATA MEASUREMENTMEASUREMENT
Bit Bytes Kilobytes (1 KB = 210 bytes) Megabyte (1 MB = 220 bytes) Gigabyte (1 GB = 230 bytes) Terabyte (1 TB = 240 bytes)
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EVOLUTION OF
COMMUNICATION
Computer’s “speed = how fast computer can process data
Every microprocessor contains a system clock
The system clock controls the speed of all the operations within a computer
The speed of the clock = how many cycles per second the clock makes
CLOCK SPEED MEASUREMENT
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The units of clock speed measurement
Hertz (Hz)
æ The clock speed unit is measured in hertz
æ A hertz is one cycle per second
Megahertz (MHz)
æMega = millionæMegahertz (MHz) = 1
million cycles of the system clock
æA computer that operates at 933 MHz has 933 million clock cycles in one second
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Gigahertz (GHz)
æGiga = billionæ1GHz = 1000 MHzæE.g. a microprocessor that runs at 200 GHz
executes 200 billion cycles per second
The units of clock speed measurement
Processing Speed
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»The system clock major factors that influence
the computer speed
»CPU with a higher clock speed can process
more instructions per second than a CPU with a
lower clock speed
»E.g. A 1 GHz CPU is faster than a CPU operating
at 800 MHz
Speed and path
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The combination of speed and number of paths
determines the total processing speed or
channel bandwidth
Different processors often use different
architectures
e.g. a 1.4 GHz Pentium 4 performs better than a
1.4 GHz Pentium 3, but it is not as fast as a 1.4
GHz Power PC G4 processor.
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A Pentium 4 running at 2.4 GHz isone-third faster than
a Pentium 4 running at 1.8 GHz
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Input devices
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Any data or instructions that we enter into the computer system for processing
Input
text
audio
Graphic
video
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OUTPUT DEVICES
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Data that has been processed into a useful form information
Output
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MOTHERBOARD
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Motherboard main circuit board of the system unit
Consist of some electronic components attached to it and others built into it
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CPUExpansion
slot
RAM
Components of a Motherboard
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RAM•Memory of the computer•Placed on the RAM slot
expansion card•Plugged into an expansion slot•Used to add new devices or capabilities to a computer
Components of a Motherboard
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Ports and connectors• The point at which a peripheral attaches to a system unit so that the peripheral can send data to or receive information from the computer
• Serial port• Parallel port• Universal Serial Bus (USB) port• FireWire port• Spécial purpose ports - MIDI port - SCSI port - IrDA port
Components of a Motherboard
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PORTS AND CONNECTORS
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Serial port
A socket on a computer used to connect a modem, data acquisition terminal or other serial devices via a slow-speed serial interface
Connect a device to the system unit by transmitting data one bit at a time
Example = COM (communication) port
A socket on a computer used to connect a modem, data acquisition terminal or other serial devices via a slow-speed serial interface
Connect a device to the system unit by transmitting data one bit at a time
Example = COM (communication) port
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Parallel port
A devices by transferring information more than one bit at a time socket on a computer used to connect
Transfer eight bits of data (one byte) simultaneously through eight separate lines in a single cable
Many printers connect to the system unit using a parallel port
A devices by transferring information more than one bit at a time socket on a computer used to connect
Transfer eight bits of data (one byte) simultaneously through eight separate lines in a single cable
Many printers connect to the system unit using a parallel port
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USB port
• A socket on a computer or peripheral devices into which a USB cable is plugged in
• Can connect up to 127 different peripherals together with a single connector
• Transfer data to a speed of 12 megabits per second
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Fire Wire port
• Previously the FireWire port is called IEEE 1394 port, a personal computer (and digital audio/video) serial bus interface standard
• Similar to a USB port in that it can connect multiple types of devices that require faster data transmission speeds
• Data can move across the port at up to 400 megabits per second
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Special purpose
port
MIDI portconnect the system unit to a musical instrument (electronic keyboard)
SCSI portspecial high-speed parallel port used to attach peripheral devices
IrDA porttransmit data via infrared light waves
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CENTRAL PROCESSING
UNIT
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CPU
an integrated circuit chip that is capable of processing electronic signals
CPU interprets instructions given by the software and carries out those instructions by processing data and controlling the rest of the computer’s components
Control Unit (CU)
Arithmetic Logic Unit (ALU)
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Control Unit (CU)
æMain function to direct the CPU to process data
æExtracts instructions from memory and decodes and executes them
æManages a four-step basic operation machine cycle @ processing cycle
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Arithmetic Logic Unit (ALU)
• Perform all arithmetic and logical operations
• Arithmetic operation is an operation that forms a function of two numbers
• Logic operation is an operation on logical values
• 16 logic operations over one or two operands (AND, OR, NOT, NAND, NOR, XOR and equivalence)
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STORAGE
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FUNCTIONS OF COMPUTER STORAGE1.Store programs and data to be used at a later time2.Keep current data while being processed by the processor until the information is saved in a storage media3.Stores instructions from a computer program
Primary storage
Secondary storage
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Primary storage • main memory in a computer
• stores data and programs that can be accessed directly by the processor
• Installed inside computers
• The data in RAM can be read (retrieved) or written (stored)
• RAM is volatile the programs and data in RAM are lost when the computer is powered off
• Stores data during and after processing
RAM
• Permanently stored inside the computer
• ROM is non-volatile• Programs in ROM
have been pre-recorded (It can only be stored by the manufacturer once it is done, it cannot be changed)
• Many complex functions
• All the contents in ROM can be accessed and read but cannot be changed
ROM
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Secondary storage
• alternative storage to keep work and documents
•useful to store programs and data for future use
•non-volatileMagnetic Medium•Non-volatile•Can be any type of storage medium that utilizes magnetic patterns to represent information• Magnetic disk (floppy disk, hard disk)•Magnetic tape (video cassette, audio storage reel-to-reel tape etc)
Optical Medium•Non-volatile•Holds content in digital form that are written and read by a laser (CDs, DVDs, CD-R, DVDR etc)
Flash Memory•Solid-state, non-volatile, rewritable memory that functions like RAM & a hard disk drive combined•Store bits of electronic data •Fast reading access times•Thumb drives, pen drives, flash drives etc
COMPUTER SOFTWARE
A program which consists of a set of instructions that tells the computer how to perform specific tasks
APPLICATIONSOFTWARE
SYSTEMSOFTWARE
SYSTEMSOFTWARE
Any software used to control and manage computer devices
and operations
APPLICATIONSOFTWARE
Any software used to help user perform specific tasks
OS, Utility program
Spreadsheet, web browser
Usage
Need
NumberOf software
Dependency
Function
System software Application software
Enable computer to function properly
Enable user to work efficiently
Compulsory Optional
One More than one
Independent
Provides environment for
application to run
Dependent
Provides environment enable user to do
specific tasks
SYSTEMSOFTWARE
OPERATING SYSTEM
A set of program that coordinates all the activities
among the computer
hardware devices
-LINUX
-Mac OS
-UNIX
-Windows XP
UTILITY PROGRAM
A type of system software that allows user to
perform maintenance type tasks to manage a computer, devices
or its program
-Antivirus
-Screen savers
-File manager
Function of OS
Starting a computer
Providing user interface
Managing data and programs
Managing memory
Configuring devices
Starting a computerOS function
❋ Booting – Loading and initialize OS into the computer’s
memory
❋ Two ways of booting
Warm boot Cold boot- Restarting a computer that is
already on
- After installing new software
or hardware / after
application stops working
- Starting a computer that is
already off
- Computer that is completely
powered off
Providing user interface
OS function
- Controls how user enters data and
instructions and how information
is displayed
- Interface enables users to;
- start an application program
- manage disks and files
- shut down computer safely
Command Line
Menu-Driven
GUI
CommandLine
➤Requires user to type command or press special
keys on the keyboard to enter data and
instructions to tell the OS what to do
➤Typed one line at a time
➤Difficult to use exact spelling, syntax or a set
of rules of entering commands
➤Advantage helps user to operate computer
quickly after memorizing the keywords and
syntax
Menu-Driven
➤ No need to memorize
keywords and syntax
➤ Provide menu to enter
commands
➤ shows all the option
available at a given point
in a form of text based
menu
➤ Easy to learn
GUI
• Friendly user, commonly used
• Operates after OS finishes loading into
memory
• Interacts with the menus and visual
images to issue commands
• On desktop can initiate many actions
by clicking icons that represents
computer resources
THE IMPORTANCE OF
USER INTERFACE✺Assists user to interact with OS
✺Control how user enters data and
instructions
✺Control how information is displayed
OS function
Managing data and programs
- CPU loads the application from storage into
memory
- Multitasking OS enable users to work
with two or more application at the same
time
Managing memory
OS function
- Optimizing the use of RAM
- Allocating data and instruction to an area
of memory while being processed- Monitoring the contents of memory
- Releasing data and instructions from
being monitored in memory when the
process is done
Configuring devices
OS function
- Handling input/output as
well as enabling
communication with i/o
devices
- Most OS comes with
drivers for popular
i/o devices
OS PLATFORMS• manufacturers produce unique
software version for each platform
ApplePlatform OS
PCPlatform OS
Cross-platformOS
ApplePlatform OS
• Used on Apple platform- Mac OS- Mac OS X
• Closed source software• For use with home desktop and
workstations
ApplePlatform OS
• Used in IBM compatible computers• Examples:
- Disk Operating System (DOS)- Microsoft Windows XP
• Closed source software• DOS - use command line interface• MS Windows XP – GUI interface
PCPlatform OS
PCPlatform OS
• UNIX Multitasking OS» Most versions of UNIX use GUI and some
use command line
Cross-platformOS
• LINUX Multitasking OS» Open source software» Free and UNIX-like GUI OS» Best known for its support of IBM-Intel
PC-based hardware
Cross-platformOS
APPLICATIONSOFTWARE
WORD PROCESSING
SPREADSHEET
PRESENTATION
GRAPHICS EDITING
• An office application enables user to create, edit, format and print textual document
WORD PROCESSING
• A program that processes information in the form of grid of columns and rows (table)
• Holds values or mathematical formulas• Indispensable if working with numbers
SPREADSHEET
• Enables user to create transparencies, slides and handouts for presentation
• Create visual aids for presentation to communicate ideas, messages and other information to a group
PRESENTATION
• A program that can edit digital representation or non-text information (drawings, charts or photographs)
GRAPHICS EDITING
APPLICATIONSOFTWARE
WORD PROCESSING
SPREADSHEET
PRESENTATION
GRAPHICS EDITING
SOFTWARE SUITE• A collection of individual programs sold as a
single package• Designed to enhance work performance • Word processing, spreadsheet, presentation and e-mail• Microsoft Office
• closed source software • stable system with support if
the software fails or malfunctions
PROPRIETARY SOFTWARE
• Provided for use, modification and redistribution
• Can download from the Internet for free and modify into better quality software
• The only qualification changes can't be copyrighted
OPEN SOURCE SOFTWARE
OPEN SOURCE SOFTWARE
OpenOffice.org, PHP-Nuke, The GIMP, Mozilla, ClamAV, OpenLDAP, Audacity and RedHat
LINUX version
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