Definations AZC


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Definations AZC

  1. 1. What is Computer? Computer is an electrical machine which accepts data and figures and after processing provides correct information. Computer is an electrical machine that can solve a no of problem in seconds. Components of Computer 1. Hardware 2. Software Hardware All those part of computer system which can be seen and touched are called hardware. For example Keyboard, Mouse, CPU, Speaker, Monitor etc. Two parts of hardware 1. Input Hardware 2. Output Hardware Input  Processing  Output Input All the fact and figures given to the computer for processing is called input Input Devices All devices which are used to enter data in the computer are called input devices. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Mouse Keyboard Scanner Micro phone Digital camera Joy stick Trac ball Bar Code Reader Light Pen Touch Screen 1. Mouse This is a pointing device which contains a roller in its base. When the mouse is moved on any surface, the pointer on the screen is also moved. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 1
  2. 2. 2. Keyboard This is most commonly used device which acts as input device. Its structure is like typewriter. Used for typing document applications. 3. Scanner The scanner is an input device like the photocopier machine which makes the electronic copy of the picture or document 4. Microphone An instrument that converts sound waves into an electric current, usually fed into an amplifier, a recorder. That used to enter sound in a computer. 5. Digital Camera A camera that records and stores digital images. 6. Joy Stick A joystick is a cursor control device used in computer games. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 2
  3. 3. 7. Track ball A trackball is a computer cursor control device used in many notebook and laptop computers. The trackball is usually located in front of the keyboard toward the user. 8. Bar Code Reader It is a device which is used to read the code from the products which are usually in the form of Bars. It contains a light sensitive detector which identifies the values of the bars on the product & converts them into numeric code. 9. Light Pen It is a pointing device which contains a photocell mounted at its tip. It senses the light from the screen when it becomes closer to the screen, & generates a pulse. So for identifying a particular location on the screen these light pens are very useful. 10. Touch Screen A touch screen is a computer screen or other screen that you can touch with your finger to enter information. Examples of touch screens include a smart board, a microwave, a dishwasher, or an ATM at a bank. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 3
  4. 4. Output The information obtain from computer after processing is called output Output Devices All those devices which are used to obtain information from the computer are called output devices. 1. Monitor 2. Speaker 3. Printer 1. Monitor A computer monitor is defined as being a piece of electrical equipment that displays images without producing a permanent record. A monitor consists of the display device, electronic circuitry, and a case that it all goes into. Computer monitors can be CRT, LCD, or Plasma. 2. Speaker Speakers are popular output devices used with computer systems. They receive audio input from the computer's sound card and produce audio output in the form of sound waves. Most computer speakers are active speakers, meaning they have an internal amplifier which allows you to increase the volume, or amplitude, of the sound. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 4
  5. 5. 3. Printer A printer is a device that accepts text and graphic output from a computer and transfers the information to paper, usually to standard size sheets of paper. Printers are sometimes sold with computers, but more frequently are purchased separately. Printers vary in size, speed, sophistication, and cost. In general, more expensive printers are used for higher-resolution color printing. Software All those part of a computer which can be seen but not touched are called software. For example Windows. Proper definition of software A set of instructions given to the computer for specific purpose is known as software. Parts of software 1. System/Operating Software 2. Application Software 1. System & Operation software The software which is necessary to run or operate a computer system are called operating or system software such as Dos Windows Linux etc. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 5
  6. 6. 2. Application Software The software which is not necessary to run or operate a computer system but it is used for user application and requirement are called application software such as Ms. Office Typing Master In page Games etc. Types of Computer Computer types can be divided into 3 categories according to electronic nature. Types of computers are classified according to how a particular Computer functions. These computer types are · Analogue Computers · Digital Computers · Hybrid Computers Analogue Computers Analogue types of Computer uses what is known as analogue signals that are represented by a continuous set of varying voltages and are used in scientific research centers?, hospitals and flight centers With analogue types of computer no values are represented by physical measurable quantities e.g. voltages. Analogue computer types program arithmetic and logical operations by measuring physical changes i.e. temperatures or pressure. Digital Computer type With these types of computers operation are on electrical input that can attain two inputs, states of ON=1 and state of OFF = 0. With digital type of computers data is represented by digital of 0 and 1 or off state and on state. Digital computer type recognizes data by counting discrete signal of (0 0r 1), they are high speed programmable; they compute values and stores results. After looking at the Digital computer type and how it functions will move to the third computer type as mentioned above. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 6
  7. 7. Hybrid type of Computer Hybrid computer types are very unique, in the sense that they combined both analogue and digital features and operations. With Hybrid computers operate by using digital to analogue convertor and analogue to digital convertor. By linking the two types of computer above you come up with this new computer type called Hybrid. Classification of Computer’s on the base of size & power Computers can be generally classified by size and power as follows, though there is considerable overlap: Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second. Mainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously. Minicomputer: A multi-user computer capable of supporting up to hundreds of users simultaneously. Workstation: A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and, in general, a higher-quality monitor. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 7
  8. 8. Personal computer: A small, single-user computer based on a microprocessor. Personal Computer Types Tower model The term refers to a computer in which the power supply, motherboard, and mass storage devices are stacked on top of each other in a cabinet. This is in contrast to desktop models, in which these components are housed in a more compact box. Desktop model A computer designed to fit comfortably on top of a desk, typically with the monitor sitting on top of the computer. Desktop model computers are broad and low, whereas tower model computers are narrow and tall. Desktop models designed to be very small are sometimes referred to as slim line models. Notebook computer An extremely lightweight personal computer. Notebook computers typically weigh less than 6 pounds and are small enough to fit easily in a briefcase. Aside from size, the principal difference between a notebook computer and a personal computer is the display screen. Laptop computer A small, portable computer -- small enough that it can sit on your lap. Nowadays, laptop computers are more frequently called notebook computers. Subnotebook computer A portable computer that is slightly lighter and smaller than a full-sized notebook computer. Typically, subnotebook computers have a smaller keyboard and screen, but are otherwise equivalent to notebook computers. Hand-held computer A portable computer that is small enough to be held in one’s hand. Although extremely convenient to carry, handheld computers have not replaced notebook computers because of their small keyboards and screens. The most popular hand-held computers are those that are specifically designed to provide PIM (personal information manager) functions, such as a calendar and address book. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 8
  9. 9. What is C.P.U (Central Processing Unit) The Central Processing Unit (CPU), also known as CPU, is the main processing chip of a computer. This chip processes the information that the various components in the computer pass to it. In current times the speed of the CPU is rated in MHz or Hz. For example 760MHz and 2.40GHz. Types of CPU The Central Processing Unit (CPU) has 2 parts, the Control Unit(CU) and the Arithmetic Logic Unit (ALU) 1) Arithmetic Logic Unit (ALU) Its divided into two parts AU (Arithmetic unit) and LU (Logic Unit) AU (Arithmetic unit) Its performed all mathematical operations such as (+,-,*,/) For example 2+2=4, 5*2=10 LU (Logical unit) Its tell us the answer is true or wrong. For example 2+2=4 True and 5*2=7 Wrong. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 9
  10. 10. 2) Control Unit (CU) Its control and manage all the process performed in CPU and Can execute or store the results coming out of the ALU. Computer Storage Devices  Primary Storage Devices  Secondary Storage Devices Primary Storage Devices Internal memory and main memory, primary storage is a storage location that holds memory for short periods of times while the computer running. For example, computer RAM and ROM are both examples of a primary storage device.  ROM (Read only Memory)  RAM (Random Access Memory) ROM (Read only Memory) Short for Read-Only Memory, ROM is a type of "built-in" memory that is capable of holding data and having that data read from the chip, but not written to. Unlike Random Access Memory (RAM), ROM is non-volatile which means it keeps its contents regardless if it has power or not. A good example of ROM is EEPROM, which is a programmable ROM used for the computer BIOS, as shown in the example picture to the right. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 10
  11. 11. RAM (Random Access Memory) RAM is an acronym for random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers. Ram is a temporary memory all programs are loading in ram and then display. If computer is off all data running in ram is loss . Types of RAM There are two different types of RAM:   DRAM (Dynamic Random Access Memory) SRAM (Static Random Access Memory). The two types of RAM differ in the technology they use to hold data, with DRAM being the more common type. In terms of speed, SRAM is faster. DRAM needs to be refreshed thousands of times per second while SRAM does not need to be refreshed, which is what makes it faster than DRAM. DRAM supports access times of about 60 nanoseconds, SRAM can give access times as low as 10 nanoseconds. Despite SRAM being faster, it's not as commonly used as DRAM because it's so much more expensive. Secondary Storage Devices      Store most of the information the computer uses Locate outside the primary storage area Non-volatile Retains data even when the computer is turned off Used for relatively long term storage of data out side the CPU 1. 2. 3. 4. 5. 6. 7. Disk drive Hard disk Floppy disk Magnetic Taps CD (Compaq disk) or Optical Disk DVD (Digital Video Disk) USB/ Flash Memory Ahmad Zafar Academy 201 Made By Raza Taqdees Page 11
  12. 12. 1) Disk Drive  The device in which the disk is made rotating  Reads data from or writes them onto the disk  Reading or writing is done via read/write heads 2) Hard Disk  The main secondary storage device of a computer system.  Available in 40 GB, 80 GB, 320 GB,500GB and even more capacities.  Composed of a pack of disks mounted on to the disk drive.  There is one read write head per each surface. 3) Floppy Disk  Can be insert into and remove from its drive whenever needed  Can be used  For transferring data from computer to computer.  As a backup media The size of today’s most popular type.   Length and width (both) = 3.5 inch Capacity = 1.44 MB  Not reliable and easily damageable.  . Used in desktop and laptop computers.  Storage capacity and the access rates are lower than hard disks. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 12
  13. 13. 4) Magnetic Taps  An older storage technology.  Still employed for secondary storage of large quantities of data, needed rapidly but not instantly.  Relatively very inexpensive and stable.  Stores data sequentially.  Relatively very slow compared to other secondary storage media. 5) CD (Compaq disk) or Optical Disk     Also called compact disks. Store massive quantities of data in a highly compact form. Available for both PCs and large computers. A 4.75-inch compact disk for PCs can store up to 700 MBs of data.  Nearly 500 times more than the capacity of a high-density floppy diskette.  They are also suitable for applications combining text, sound, and image. 6) DVD (Digital Video Disk)  Digital video disks (DVDs), are optical disks having the same size as CD-ROMs but of even higher capacity.  Can hold a minimum of 4.7 GBs of data.  DVDs are enough to store full length, high quality motion pictures, movies and multimedia applications. 7) USB( Universal Serial Bus) or Flash Memory  The flash drive is removable and portable.  The drive and the storage device both are compactly built into a single small unit.  Available in 1 GB, 2 GB, 4 GB, 8 GB, 16 GB or even more .  Ahmad Zafar Academy 201 Made By Raza Taqdees Page 13
  14. 14. Storage measuring units  8 bits  1024 bytes  1024 KB  1024 MB  1024 GB Ahmad Zafar Academy 201 = = = = = 1 Byte 1 Kilo byte (KB) 1 Megabyte(MB) 1 Gigabyte (GB) 1 Terabyte (TB) Made By Raza Taqdees Page 14
  15. 15. System Buses A bus, in computing, is a set of physical connections (cables, printed circuits, etc.) which can be shared by multiple hardware components in order to communicate with one another. The purpose of buses is to reduce the number of "pathways" needed for communication between the components, by carrying out all communications over a single data channel. This is why the metaphor of a "data highway" is sometimes used. There are three types of system buses. 1. Data Bus 2. Address Bus 3. Control Bus 1. Data Bus A bus which carries data from one part of computer to another part is caller data bus 2. Address Bus A bus which carries address at which the data needs to be placed is called address bus 3. Control Bus A bus which helps the control unit to control all the functions and operation of the computer is called control bus. Bus Throughput To get the total throughput capability of the bus, multiply the bus clock speed in hertz times the number of bits 'wide' the bus is. Data Busses are almost always a multiple of 8 bits wide (8, 16, 32, 64 etc.) For instance: 33 MHz x 32 bits = 1,056 mbps/sec 200 MHz x 64 bits = 12,800 mbps/sec (12.8 gbps) Ahmad Zafar Academy 201 Made By Raza Taqdees Page 15
  16. 16. Ahmad Zafar Academy 201 Made By Raza Taqdees Page 16