Lesson 1 0x001 001 The Computer System Mohamed Zaki Principal Lecturer Computer Systems / Ch. 1

Main Topics What is a Computer? General-purpose & Dedicated Computers. Computer as a system. Computer hardware system. Peripherals Input Peripherals. Output Peripherals. Storage. Computer Systems / Ch. 1

Course Assessment Attendance & Contribution 10 Assignments (2) 20 Presentation Midterm Final 40 Computer Systems / Ch. 1

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. 1

General Purpose and Dedicated Computers General-Purpose computer solves many types of problems, such as (document typing, Drawing, games,..etc) Dedicated Computers is used for only one task. (Control process in the manufacturing industry) Computer Systems / Ch. 1

General Purpose and Dedicated Computers (cont.) Remark: In general a dedicated computer is the same as a general-purpose computer in its fundamental construction Computer Systems / Ch. 1

Computer as a system System: is a set of interrelated components working together to achieve a certain goal. So, to consider a computer as a system, the computer must contain related components working together to perform the main functions. Computer Systems / Ch. 1

Computer Components As a System Computer System Hardware Software Peripherals Central Processing System Programs Application Control Unit ALU Main Memory Input Unit Output Unit Secondary Storage Computer Systems / Ch. 1

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. 1

Peripherals Parts of computer that transfer data in and out. Input Peripherals. Output Peripherals. Secondary Storage. Computer Systems / Ch. 1

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. 1

Other input peripherals: Light pens. } Mice } Pointing devices Touch screens. } Digitizers. Scanners. Microphones. Cameras. Computer Systems / Ch. 1

Output Peripherals Printers 1- Impact Printer: this method of printing is based on the impact of a hard object against an ink-coated ribbon, which is then forced on the paper to make it mark the shape of the character. Computer Systems / Ch. 1

Output peripherals (Impact Printers) (Cont.) Line printers Dot matrix printers Computer Systems / Ch. 1

Output peripherals (cont.) 2- Non-Impact Printers Ink-jet printers. Thermal printers. Laser printers. Computer Systems / Ch. 1

Comparison between printers Disadvantages Advantages Mechanism Impact/Non-impact Type Low quality. Used ordinary papers. Not expensive. It prints a whole line of text at one go. Impact Line printer Low speed. noisy cheap Use a pattern of dots in the shape of a character. Dot Matrix Ink is expensive compared with printer cost. High speed. Silent. Colored Sprays a stream of ink on an ordinary paper. Non-impact Ink-Jet Slow. Paper is costly. Use heat to produce an image on special paper. Thermal Expensive Large compared with others. High quality. A laser beam is used to dry up a powdered ink on the paper. Laser Computer Systems / Ch. 1

Output peripherals (Cont.) Plotters. Visual Display Unit(VDU). Projectors (Data Show) Computer Systems / Ch. 1

Secondary Storage Optical Storage Flash Memory - CD (Compact Disc) - DVD (Digital Versatile Disc) Flash Memory Computer Systems / Ch. 1

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. Kilo Byte (KB)=1024 B =210 B Computer Systems / Ch. 1

Storage Units of Memory Mega Byte (MB)=1024 KB =(1024 x 1024) B =104,8576 B = More than a Million of bytes. =210 x 210=220 B. 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. =210 x 210 x 210 = 230 B. Computer Systems / Ch. 1

Storage Units * % 8 1024 1024 1024 1024 Bit Byte KByte MByte GByte Computer Systems / Ch. 1

Refreshing Questions The ……………………. Can be described as an input device. 1.Light pen 2.HP laser jet printer 3. Plotter 4.None A device used for transferring a paper based image into a computer image is………………. 1. Ink jet printer 2. Scanner 3. Digitizer 4. None Computer Systems / Ch. 1

Refreshing Questions (cont.) RPM stands for _________. DVD stands for _________. VDU stands for _________. 10 MB =_____ KB. Arrange the following in ascending order: 0.6GB, 840MB, 15000KB Computer Systems / Ch. 1