Introduction to Computer in Education

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Introduction to Computer in Education:

Introduction to Computer in Education Chapter # 2 Computer Hardware Section A Group 2 Presented by Nazia Tabasum.

Computer:

Computer A device that computes, especially a programmable electronic machine that performs high-speed mathematical or logical operations or that assembles, stores, correlates, or otherwise processes information .

Computer Hardware :

Computer Hardware Computer hardware are the physical parts of the computer system. We can easily touch or see these parts. These includes: Input Devices e.g. Keyboard, Mouse, Scanner etc. Output Devices e.g. Monitor, Printer, Plotter etc. CPU (Central Processing Unit) Primary Memory Devices e.g. ROM, PROM, RAM etc. Secondary Memory Devices e.g. Floppy Disk, Compact Disk etc.

Central Processing Unit (CPU):

Central Processing Unit (CPU) The combination of microprocessor and Ram is called CPU. Microprocessor is the brain of the computer. CPU is located on the motherboard inside the system unit. CPU is the centre of all activities and it is the unit which changes input to output.

Slide 6:

MOTHER BOARD

Slide 7:

CPU contains the following main components: i. Control Unit ii. Main Memory iii. Arithmetic Logic Unit (ALU) Ram Rom Control Unit ALU Main Memory

1. Control Unit:

1. Control Unit The control unit is the most important component of the CPU. It controls and coordinates the activities of all other units of the computer. Control Unit obtains instructions from the programs, stored in RAM then interprets the instructions from signals which cause the ALU to execute them. Control Unit Board Bottom Top

2. Arithmetic Logic Unit (ALU):

2. Arithmetic Logic Unit (ALU) ALU carries out all the Arithmetic logic functions required in data processing. ARITHMETIC OPERATIONS

Data Processing:

Data Processing The whole process of information or data processing can be thought of as a cycle of input, processing and out, which are often followed by more input.

Input Devices:

Input Devices Input devices are used to enter data and instructions into the computer. The input devices are the eyes and ears of computer. A list of most popular and most commonly used input devices is given as:

1. Keyboard:

1. Keyboard The keyboard is the most common data entry device in a computer system. The buttons on the keyboard are called keys. A standard keyboard used in personal computers contains more than 100-keys.

Parts of keyboard :

Parts of keyboard A standard keyboard may be divided into four parts. Function keys There are 12 function keys on the top of the keyboard.

II. Main keyboard:

II. Main keyboard The main keyboard area is like typewriter. It includes alphabetic character keys, numeric keys and some special command keys e.g. Esc, Caps Lock, Shift, Ctrl, Alt, Tab, Backspace, Enter etc…

III. Numeric keys:

III. Numeric keys This part consists of numeric keys and arithmetic operator keys. These keys are similar to calculator keys. These keys are also used to perform Mathematical operations (such as /, *, -, +).

IV. Additional Keys:

IV. Additional Keys Extended keyboards also have some additional keys like Arrow Keys, Insert, Delete, Home, Scroll Lock, Print Screen etc…

2. Mouse :

2. Mouse A mouse is a pointing input device. It is most commonly used in windows environment on the personal computers. It is used to control the cursor or pointer on the screen. A mouse is connected to a Serial Port or USB port on System unit.

A mouse has a ball in its bottom when it moves, a pointer moves at the monitor screen. The mouse has two or three buttons on its top. :

A mouse has a ball in its bottom when it moves, a pointer moves at the monitor screen. The mouse has two or three buttons on its top . The graphic designer cannot draw graphs with out mouse.

Types of Mouse:

Types of Mouse Mechanical mouse It has metal or rubber ball at its bottom and an electronic circuit containing sensors. The ball moves in response to our moving the mouse across a surface.

Optical Mouse:

Optical Mouse It has advanced features and more expensive than mechanical mouse. It has no ball inside. It uses laser technology to detect the mouse.

Cordless Mouse:

Cordless Mouse Cordless or wireless mouse is not connected to the computer. It uses the wireless technology, such as radio waves or infrared light waves.

3. Scanner:

3. Scanner A scanner is a very popular and light-sensing input device. It can be used to input printed images or pages of text directly into the computer. It converts documents or pictures in Digital signals and we can save, print or watch them on monitor screen.

4. Light Pen:

4. Light Pen The light pen is a handheld input device. It is connected with the computer by wire. When the pen is pointed at the screen the computer can work out where the pen is pointing. Light pen devices are used by engineers, graphic designers and illustrators. These devices require special monitors. Light pen is hardly ever used today.

5. Joystick:

5. Joystick Joysticks are used to play computer games. A joystick may also have several buttons which can be pressed to trigger actions such as firing a missile. We can move a standard joystick in any one of eight directions.

6. Digital cameras:

6. Digital cameras These are used in the same way as standard photographic cameras. A digital camera uses a light-sensitive processor chip to capture photographic images in digital form. These images are stored on a small diskette inserted in the camera or on flash memory chip.

Output devices:

Output devices The data processed into a useful form is called output. Hardware components which are used to receive the output from the computer are called output devices. A list of commonly used output devices is as :

1. Monitors:

1. Monitors Video monitor or Video Display Unit is the most commonly used as output device. It works like a T.V. it has a cathode Ray Tube that works like a T.V screen. But it has no ability to receive T.V signals.

2. Printers :

2. Printers These are the most commonly output devices used to get printers of documents on the paper. A printer is connected to a parallel port or USB port of system unit by a cable. Printers are classified into two main categories. 1. Impact printers 2. Non-impact printers

1. Impact Printers:

1. Impact Printers Impact printers work like a typewriter, approach of hammering a typeface against paper and inked ribbon.

The examples of impact printers are::

The examples of impact printers are: i. Dot Matrix printer Dot matrix printers are used with personal computers. It printing speed varies from 200 ti 100 or more characters per minute. They are less expensive. They also produce noise while printing and not having good printer quality.

2. Daisy Wheel Printer:

2. Daisy Wheel Printer It is similar to typewriter. It has print wheel with series of petals. This wheel is known as daisy wheel. A motor rotates the wheel. A desired character is printed when a hammer strikes a petal against the ribbon.

3. Line Printer:

3. Line Printer Line Printer is very fast. It print a complete line of characters at a time. The printing speed of the line printer is measured in lines per minute (lpm). It is up to 3000 lines per minute.

2. Non-Impact Printers:

2. Non-Impact Printers Non-Impact printers do not hit a ribbon to print. They use thermal, electro static, chemical and inkjet technologies. The examples of non-impact printers are; 1. Laser Printer 2. Inkjet printer 3. Thermal printer

1. Laser printer:

1. Laser printer LASER stands for Light Amplification by Stimulated Emission of Radiation . It is the fastest and high quality non-impact printer. The laser printer can print both text and graphics in very high quality resolution. Laser printers are used by companies where “Book Quality” is required.

2. Ink-jet printer:

2. Ink-jet printer Inkjet printer creates output on paper by spraying small electrically charged droplets of liquid ink. Inkjet printer are slower and have low print quality than laser printer.

3. Thermal Printer:

3. Thermal Printer Thermal printer can only print output on a special heat sensitive waxy paper. Thermal printer produces a high quality print out. It is quite expensive as compared to other non-impact printers.

3. Speaker and Headset:

3. Speaker and Headset Speakers are used to receive audio output from the computer. The speaker is connected to the computer through the port of sound card. The headset is used for the solution of the sound quality problems.

4. Projector :

4. Projector With the help of projector, we can display information on a larger screen. Projectors are mostly used in colleges and universities for teaching purposes. It is very easy, efficient and fast way to deliver lectures.

Primary Memory Devices:

Primary Memory Devices The memory unit is the most important part of the computer. The main memory is also called the Primary Storage. It is used to store data and instructions. In computer, there are two types of memories. Volatile Memory : It is a temporary memory. RAM is an example of volatile memory. 2. Non-volatile Memory : It is a permanent memory. It does not lose its content when computer is turned off. ROM is an example of non-volatile memory.

Basic Storage Units of Memory:

Basic Storage Units of Memory The basic storage units of memory are described below. BIT : The binary digit 1 or 0 is called a BIT. It is the basic unit for storing data. BYTE : A combination of 8-bits is called BYTE. One character takes one byte of memory. The data and program size are measured in bytes.

Units of data and Memory:

Units of data and Memory The commonly used storage units are as follows. 1 Nibble = 4 – bits 1 Byte = 8 – bits 1 Kilo Byte (KB) = 1024 Bytes 1 Mega Byte (MB) = 1024 Kilo Bytes 1 Giga Byte (GB) = 1024 Mega Bytes 1 Tera Byte (TB) = 1024 Giga Bytes 1 Peta Byte (PB) = 1024 Tera Bytes

RAM – Random Access Memory:

RAM – Random Access Memory RAM is a volatile memory, depends on the availability of electricity, this means that any data it holds is lost the moment the computer is switched off. The main use of RAM is as a temporary store for the data and program currently in use on the computer. The maximum capacity of RAM to store instructions or data is 128 MB .

ROM – Read Only Memory:

ROM – Read Only Memory ROM is one in which information is permanently stores. It is also called permanent storage device. When power supply is switched off, the information stored inside the ROM is not lost. ROM is used to stored the programs which are needed for the operationsof the computer – “boot” programs and BIOS programs.

ROM is divided into following types ::

ROM is divided into following types : PROM : PROM stands for Programmable Read Only Memory . It is variation of ROM chip. User can customize his computer by converting his own programs to micro programs and storing them in a PROM chip. Once the chip has been programmed, the recorded information can not be changed.

2. EPROM:

2. EPROM EPROM stands for Erasable Programmable Read Only Memory. This type of storage solves the problem to write and erase the instructions on the ROM. So, program or data written in EPROM chip can be changed and new data can also be added. When EPROM is in use, it contents can only be read.

3. EEPROM:

3. EEPROM EEPROM stands for Electricity Erasable Programmable Read Only Memory. This kind of ROM can be written or changed with the help of electrical devices. So, data stored in this type of ROM chip can be easily modified.

Secondary Memory Devices:

Secondary Memory Devices The storage capacity of Primary storage of today’s computer is not sufficient to store the large volume of data. As a result additional memory called Secondary storage is used with the most computer systems. A wide rage of secondary devices is available. There are two major categories of Secondary devices. Magnetic Storage Devices : Diskette drives, tape drivers and hard disk are the examples of magnetic storage devices. These devices are used to write and read data to and from the diskettes, tapes and hard disks. ii. Optical Storage Devices : These devices use laser technology to store and read data to and from the disk. CD-ROM drive and DVD-ROM drive are the examples of these devices.

We study here five types of secondary storage devices.:

We study here five types of secondary storage devices. Floppy Disks Floppy disks are very popular type for personal computers. It may look or work like a small stereo cassette. They usually come into two sizes. 3.5-inches Floppy Disk : capacity of 1.44 MB 2. 5.25-inches Floppy Disk

2. Hard Disk:

2. Hard Disk Hard Disk is the most popular secondary device for the personal computer. It can store a large quantity of programs (software) and the data in it. Hard disk usually has more data storage capacity than a floppy disk and a CD-ROM. Hard disk is compulsory for every computer.

3. Magnetic Tape:

3. Magnetic Tape Magnetic Tape is the most popular and oldest storage medium. It is used to store large amount of data permanently. The magnetic tape is a plastic ribbon with width of 0.25 to 1 inch. The tape unit can be internal and external to a computer system.

4. CD – ROM :

4. CD – ROM CD – ROM stands for Compact Disk Read Only Memory . A CD-ROM’s capacity is also measured in terms of how much data a CD can store. Normally a CD-ROM has the capacity of 700 MB which is more than the capacity of 450 floppy disks.

5. DVD – ROM :

5. DVD – ROM DVD stands for Digital Video Disc or Digital Versatile Disc. DVD-ROM is an extremely high capacity optical disc with storage capacity from 4.7 to 17 GB. It is also used to store huge databases, music, complex software etc.