1. The Computer Computer Systems / Ch. 11 Mohamed Zaki Principal Lecturer

2. Main Topics What is a Computer? Computer system. Peripherals – Input Peripherals. – Output Peripherals. – Storage. Units Computer Systems / Ch. 12

3. What is a Computer? Computer: is a programmable machine that receives input, stores and manipulates data/information, and provides output in a useful format. Computer Systems / Ch. 13

4. General Purpose Computer 1.General-Purpose computer used in many applications, such as (document typing, Drawing, communication, games,..etc) Computer Systems / Ch. 14

5. Computer Components As a System Computer Systems / Ch. 15 Computer System Hardware Software Peripherals Central Processing Central Processing System Programs System Programs Application Programs Application Programs Control Unit ALU Main Memory Input Unit Output Unit Secondary Storage MS-Word MS-Excel MS-Power Point MS- Access MS-Windows

6. 1-Computer Hardware Hardware devices can be organized according to the following system functions: Input: Devices that convert data into electronic form in the computer system. Output : The output devices are used to convert the electronic information into a human understandable form. Processing: The CPU is the main processing component. ALU (Arithmetic Logic Unit) will perform all the processing. Storage: Takes place in the primary storage unit of the CPU and in secondary storage units. these devices store data and program instructions are needed for processing. Control: control unit of the CPU is the control component of the computer system. It interprets computer program instructions and transmits directions to other components of the computer system. Computer Systems / Ch. 16

7. Peripherals Parts of computer that transfer data in and out. Input Peripherals. Output Peripherals. Secondary Storage. Computer Systems / Ch. 17

8. Input Peripherals: Devices used for transferring data from the outside world representation into the internal character code of the computer. Keyboard. Barcode reader: Barcode data can be described as a sequence of vertical lines vary in thickness, light focuses on and scanned across these lines using a small laser beam, then data can be read and input to computer. Computer Systems / Ch. 18

9. Other input peripherals: Light pens. } Mice } Touch screens. } Digitizers. Scanners. Microphones. Cameras. Computer Systems / Ch. 19

10. Secondary Storage Hard disks Optical Storage - CD (Compact Disc) - DVD (Digital Versatile Disc) Flash Memory Computer Systems / Ch. 110

11. Storage Units Bit (Binary Digit): it is the smallest unit to store data,(0 or 1). Byte (B) :it is the basic storage unit of memory. It consists basically of 8 bits. It can hold one symbol only at a time such as “A”, “a”, “$” and so on. Symbols are converted into binary codes Kilo Byte (KB)=1024 B =2 10 B Computer Systems / Ch. 111

12. Storage Units of Memory 4.Mega Byte (MB)=1024 KB =(1024 x 1024) B =104,8576 B = More than a Million of bytes. =2 10 x 2 10 =2 20 B. 5.Giga Byte (GB)=1024 MB =(1024 x 1024) KB =(1024 x 1024 x1024) B =104,8576 KB = 1,073,741,824 B = More than a Billion of bytes. =2 10 x 2 10 x 2 10 = 2 30 B. Computer Systems / Ch. 112

13. Storage Units % Bit Byte KByte GByte MByte TByte * 8 1024

14. Refreshing Questions 10 MB =_____ KB. Computer Systems / Ch. 114 Which program allows you to produce letters, memos etc. A.Database Application B.Photo editing C.Web browsing D.Word processing

15. Refreshing Questions Computer Systems / Ch. 115 Which one of the following used as input device? a)Printer b)Monitor c)Scanner d)Plotter

16. Refreshing Questions List main four types of Hardware, and give one example for each. Computer Systems / Ch. 116