1. Basics of the Computer System
Bayram Güzer

2. A Computer System A computer system consist of three main components:
Hardware
Software
People
Software is a set of instruction which tells hardware what to do
People use the computer for some purposes and without people computer can be meaningless.

3. A Computer System Software is also called as programs.
A program is a set of step-by-step instructions that guides the computer to do the required tasks and produce the desired results.
A computer programmer is a person who writes programs.
Users are people who purchase and use computer software. They are also called as end-users.

4. Basic Components of a Computer Hardware
What does a computer machine do?
It is programmed to accept data as input
It process data into useful information as output
It stores the information in a secondary storage
Processing of input to output is directed by the software but executed by the hardware

5. Basic Components of a Computer Hardware
Outside the computer
In order a computer to function, it requires four main aspects of data handling;
Input
Processing
Output
Storage
Accepts Data
Shows it to people
Until storing
it into secondary storage

6. A Personal Computer System

7. Input
Input is the data that you put into the computer system for processing.
Keyboard is one of the most common input devices which consist of keys arranged in much the same way as those on typewriter.

8. Input A mouse is a device that is moved by hand over a flat surface.
As the ball on its underside rotates, the mouse movement causes corresponding movement of a pointer on the computer screen.
When you press the buttons on the mouse, it lets you select commands.

9. Input
Another input method is through scanning with a wand-reader or bar-code reader.
These devices are used in retail stores commonly.
A stripped bar-codes found on many products which each line is represented with a character and codes are read through a bar-code reader.
Sample Bar-Code from Code 128

10. Processing
The processor which is also called as central processing unit (cpu) is the center of the activity which consist of electronic circuits that interpret and execute program instructions, communicate with input, output and storage devices.

11. Processing Data is the raw material to be processed by a computer.
Ex; grades of an exam.
When data is organized into useful and meaningful form, it becomes information.
Ex; An instructor could enter various student grades as data and when he process this data in order to produce final grades or class average, by this way he produces information.
Data: student grades
Information: final grades and class average

12. Primary Storage
Primary storage which is also known as memory has close relationship with central processing unit but it is separate from the CPU.
When data is fetched from input, it is kept in memory as temporarily.
Next data is processed, displayed on a output device and then it is still kept in memory as temporarily.
When data is stored into secondary storage and the file is closed, then it is removed from the primary storage.

13. Primary Storage
Memory also holds the programs (computer instructions) that is requested by the CPU.
Primary storage devices require continuous flow of present electric and when there is no electric present (no power), all the data in the primary storage is lost.

14. Output
Output is the result produced by the central processing unit which is the whole meaning of computers.
Most common output devices are;
Computer screens
Printers
Computer screens which is also called as monitors is used to display the output to users.
Monitors can vary in its forms of display.

15. Output
Printers produce printed reports as instructed by computer program.
Many printers can print in color or black/white.
Some of the most common printer types are ink-jet and laser-jet printers.

16. Secondary Storage
Secondary storage provides additional storage separate from memory.
There are three most-common storage media which are
Magnetic disk
Optical disk
Magnetic tape

17. Secondary Storage A magnetic disk can be diskette or hard disk.
A diskette usually consists of a magnetic disk 3 ½ inches in width, enclosed in a plastic case.
Hard disks usually have more storage capacity than diskettes and data access is faster than diskettes.
Hard disks were contained in hard disk drives and the data is read by the disk drive through hard disk drive head.

18. Secondary Storage
Optical disks use laser beam to read large volumes of data and it is relatively inexpensive in comparison to magnetic disks.
Some of the common optical disks are;
Compact Disk (CD) (up to 0.73 GB)
Digital Versatile Disk (DVD) (up to 17 GB)
High Definition DVD (HD DVD) (up to 60 GB)
Blu-ray Disk (BD) (up to 50 GB)

19. Secondary Storage
Magnetic tape data storage is usually used in large computer systems
Example; servers
This kind of tapes comes in a special cartridges and they are similar to the tapes that we usually listen music from tape recorder.
In order to use a magnetic tape, a magnetic tape drive is needed.
It is usually used in backup and archiving because tape is inexpensive than other media

20. The Complete Hardware System
The hardware devices attached to the computer are called peripheral equipment.
Input, processing, output and secondary storage devices are all peripheral equipments.
In personal computers all these equipments can be found in a metal case.
In some business computers, input, processing, output and secondary storage can be in different rooms.
Ex: computing systems of banks
But, all the computers have input, processing, output and secondary storage devices.

21. Classification of Computers
Computers vary in sizes from tiny to enormous (huge) in both appearance and power.
The type of the computer that is need by a person or an organization depends on the computing requirements.
There are five main types of computers
Personal Computers
Notebook Computers
Handheld Computers
Mainframes
Supercomputers
Sometimes this classification can overlap because of the developments in the computing industry.

22. Personal Computers
Personal computers sometimes called as PCs, desktop computers, microcomputers and home computers.
There are types of personal computers;
Low end: cheap PCs
Word processing, personal finance, record keeping, games and access to the Internet
Upper end: workstations
Usually used by the engineers, financial traders, and graphic designers.
Fully powered personal computers: not like low end or upper end PCs.
Graphic images, heavy-duty calculations, programming and action oriented arcade games.

23. Personal Computers
There is also another type of personal computers which is the network computer (NC) or net computer
Limited piece of hardware with cpu, minimal memory and the Internet access
Usually connected to the Internet over a telephone line
Usually it is a set with a television and people can use television as a computer screen
They usually don’t have disk storage
Simplicity and low price are the important characteristics of the net computers.

24. Notebook Computers
Notebook computers are portable and functional and they are popular for travelling availability
Fits in a briefcase
Weights less
You can carry it to anywhere you’re travelling
They are more expensive than desktop computers
They have all the hardware that desktop computers have such as hard disk, dvd-rom, sound card, etc…

25. Handheld Computers
Handheld computers are also called as personal digital assistants (PDAs)
They are capable of keeping track of appointments, business information, customer names and orders, etc…
They are also called as pen-based computers.
Because some of them are capable of handwritten input directly from touch-sensitive screen
They have wireless Internet capabilities

26. Handheld Computers
Usually used by clipboard-carrying workers, businessmen or workers who on their feet all day.
Parcel drivers
Nurses
Sales representative
Businessman who keep their work organized
Another type of handheld computer is pocket pc.
Offers capabilities of PDAs and stripped-down versions of software such as word processing and spreadsheets applications

27. Mainframes Large computers are called as mainframes.
Mainframes are capable of processing data at very high speeds and have access to billions of characters of data (millions of instructions per second).
Some of the customers are
banks,
insurance companies,
manufacturers,
large mail-order houses,
airlines with sophisticated reservation system,
government accounting services,
aerospace companies,
servers.

28. Mainframes
Mainframes are designed for multiple-users at the same time.
They are also called as servers or large server depending on the type of the mainframe.
Price vary between $ to $

29. Supercomputers
The most expensive, powerful and the fastest computers are called as supercomputers.
They can process trillions of instructions per second.
Used for some of the activities which require huge amount of data manipulation.
Some of the activities for supercomputers are;
Stock analysis
Weather forecasting
Weapons research
Special effects for movies

30. References Capron, H. L. (2000). Computers Tools for an
Information Age.(6th ed.). New Jersey, USA: Prentice Hall.
Barcode. (2009). Retrieved 17 October from
Code128. (2009). Retrieved 17 October from
Online Barcode Generator. (2005). Retrieved 17 October 2009 from
Intel 80486DX2. (2009). Retrieved 17 October from
Central Processing Unit. (2009). Retrieved 17 October 2009 from
Computer Parts. (2008). Retrieved 17 October 2009 from
LCD Monitor. (n.d.). Retrieved 17 October 2009 from

31. References
CRT Monitor. (2009). Retrieved 17 October 2009 from
Inkjet Printer. (2007). Retrieved 17 October 2009 from
Laserjet Printer. (n.d.). Retrieved 17 October 2009 from
Hard Disk Drivers. (2001). Retrieved 17 October 2009 from
Optical Disk. (2009). Retrieved 17 October 2009 from
Magnetic Tape. (n.d.). Retrieved 17 October 2009 from