information technology. computer generations the computer passed through develop stages these stages...
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1Computer GenerationsThe computer passed through develop stages these stages or generation are:Computer GenerationsComputer GenerationsFirst Generation (Vacuum Tubes)They relied on the machine language to perform operations. They were huge in size.They were very expensive.They had very low processing speed.
4Computer GenerationsSecond Generation (Transistors)It is smaller.It is faster.It is cheaper.
5Computer GenerationsThird Generation (Integrated Circuits)The speed and the efficiency of the computers were increased.
6Computer GenerationsFourth Generation (Present Microprocessor)The most powerful.Can be linked together to form networks.They are the fastest and the most efficient.
7DefinitionsComputer:A computer is an electronic machine that receives input, stores and automatically processes data, and provides output in a useful format.
Information Technology:A term that refers to both the hardware and software that is used to store, retrieve and manipulate information.
8DefinitionsData: Data is raw & unorganized facts and figures that need to be processed.
Information:When data is processed and organized to make it useful and meaningful, it is called Information..
Advantages of computersSpeed and accuracy of calculations and processing.Save huge amounts of data.Economic in cost and time.Network communications.
10Types of computer
11Super computerThe biggest and the most powerful.They are rare because of their cost and size.Used by companies like NASA.
12Mainframe computerGreat processing speed and data storage.Often connected to many individual PCs with limited processing capabilities called dumb terminals.Used in Banks, Airlines etc.
13Minicomputer Minimized in size and power. They are not used very commonly these days.
14MicrocomputerCalled Personal computer (PC)It is small enough to fit on top of a desk, which can be used by one user at a time.Used in homes, schools etc..
15Workstation ComputerHigh-endmicrocomputer.Used by one person at a time.They are commonly connected to alocal area networkThe workstation term can be also used to refer to aPC connected to anetwork.
16Control computerUsed for controlling operations in industrial, medical devices and travel media like planes and carsAlso used to alert in any dangerous case.
17Parts of Personal computers
1819DefinitionsHardware:The physical parts of a computer which you can see and touch.
21Hardware1) Input Devices
221) Input devicesDevices used to translate the data into a form that the computer can process.
23a) KeyboardIt is a board containing the keys of letters, numbers and some functions which allows you to type information into the computer.
24b) MouseA small hand-held device used to point, select, click on items and to drag and drop items from one place to another.
25C) ScannerIt allows you to scan pictures, text and images and save it to your computer in a digital form.
26d) Bar Code Reader
Photoelectric scanners that translate the bar code symbols into digital form.E) JoystickSmall hand-lever that can be moved in any directions to control movement on the screen.It can be used for playing games.
28Hardware2) Output Devices
292) Output devicesDevices used to translate the processed information into a form that humans can understand.30a) Monitor (computer screen)It displays the text, information and pictures.
They are different in (Size and Resolution)
31b) PrinterIt produces a hard copy of the material you are working on.
Types:1) Laser Printer 2) Ink-jet Printers
32C) PlottersIt is similar to a printer but allows you to print larger images.
33D) Speakers / HeadphoneThey are used to output voice from a computer
34Some devices can be used as both Input and output devices at the same time such as:Touch Screen:It receives input from the touch of a finger.
35Hardware3) Processing unit
36CPU ( Central Processing Unit )The most important part of a computer system.
Usually referred to as the brain of the computer.
It determines the speed of your computer which measured in MHz or GHz.1 GHz= 1000 MHz
37CPU ( Central Processing Unit )CPU consists of:CU (Control Unit): It tells the computer system how to carry out program instructions from the memory. It controls and coordinates all activities of the computer.
ALU (Arithmetic and Logic Unit): It performs mathematical and logical operations 4) Memory unitHardware39a) RAM (Random Access Memory)The operating system is loaded into the RAM when you switch on your computer. Used to store applications that you are currently working with. It is temporary (volatile).
40b) ROM (read only memory)It has special programs which are built-in when you buy the computer.Used to store control programs.It is permanent (non-volatile)
41Hardware5) storage Devices
42Storage DevicesHardware devices which are used to record and store data.
1) Internal storageHard disk:It is the most important storage media in the computer.It stores operating system and programs.
2) External Storagea) Flash MemoryA compact and easy-to-use device for transferring data between computers.
45b) CD (Compact Disk)An optical disk which uses laser to read information.It has 750 MB capacity.
46c) DVD (Digital Versatile Disk) A high-density video disc that stores large amounts of data, especially high-resolution audio-visual material like movies, encyclopedia etc.
The capacity is up to 17 GB.
Disk and memory capacityThe first level of storage is called bit ( the bit is referred to a binary number 0 or 1).Byte = 8 bits.Kilo Byte (KB) = 1024 bytes.Mega Byte (MB) = 1024 KB.Giga Byte (GB) = 1024 MB.Tera Byte (TB) = 1024 GB.48Computer PerformanceThe speed of the processor.The capacity of RAM.The capacity and the speed of the Hard disk.49