A computer is a machine that is used to store and process data electronically Computer Definition
Types of computer : 1- Personal Computer 2- Network Computer 3-laptop computers 4-PDA 5-Mainframe
Computer components SoftwareHardware
Hardware: - Pieces of equipment that make up a computer system. - These are the parts you can touch (although many parts are contained within the computer’s case).
1+2 3 memory Brain 1+2
Input devices 3 Output devices Memory Brain Computer
Computer hardware Storage devices Output devices Input devices memory Central Processing Unit CPU
Touch screen Electronic board
Any devices that allows the result of computer processing activity to be seen or heard
Output device: The screen : CRT LCD Plasma
Plotter Speakers
Data Show
Memor y (RAM)(ROM)
Storage drives are used to store and transfer data files. After data is entered into a computer, it must be saved as a file to preserve its contents after the computer is switched off.
Hard disk Drive: HDD Usually fixed inside the computer and stores large volumes of data, which can be accessed and retrieved quickly. A software application must also install files onto the hard disk drive in order to run. The access time of a HDD is measured in milliseconds(msec)
Floppy disk drive: A floppy disk drive is like a hard disk, but with removable disks called floppies, floppy disks or diskettes. Floppies can be used to transfer small files from one PC to another (up to 1.4MB) CD-ROM/DVD-ROM Drive: CD-ROM (Compact Disk – Read Only Memory) CD-ROM -> CD-R -> CD-RW -> DVD -> DVD-R Other Types of storage devices??
AA Byte Bit Storage Capacity uses several terms to define the increasing amounts of data that can be stored
: the amount of storage space needed to hold either a 1 or a 0 in memory (binary numbering ).This is the smallest unit of computer memory bit Equal to 8 bits, this is the amount of storage space needed to hold one character byte bytes 1024Kilobyte(KB) 1024 KBMegabyte(MB) 1024 MBGigabyte(GB) 1024 GBTerabyte
The user can judge the performance of a PC according to how quickly tasks are performed. Factors determine the overall operating speed of a PC: The clock speed of the CPU The Capacity of the RAM The Capacity and speed of the HDD
Computer components SoftwareHardware
Operating Systems software : Is the software that runs the computer Microsoft Windows is the operating system a lot of people use. However, there are other forms of Operating systems software such as Unix, Linux, OS2, BeOS, OS-X (MacOS) and so on Operating system cannot run without the BIOS (Basic Input Output System)
Common Applications Software Word Processing: Example Microsoft Word Spreadsheets:. Example Microsoft Excel Database: Examples Microsoft Access Presentation: Example Microsoft PowerPoint Web browsing Applications Software must be compatible with the Operating Systems
BIOS (Basic Input Output System) Sara Turn on her computer and then open the word processor to write her homework : What are the steps taken by the computer to do this task in order: Load MS word intothe RAM Run the BIOS software from the ROM the BIOS crries out the Power On Self Test(POST) read the OS files from HDD and copy them to the RAM
two or more computers connected together is called a network
Local Area Network(LAN) Wide Area Network(WAN) less than one square kilometre is a LAN While any network covering more than one square kilometre is WAN.
Internet : a vast computer network. Which allows users all over the world to communicate with each other. Connections to the internet are made by an Internet service Provider (ISP) Intranet: Many medium to large organizations now operate their own internal networks that provide similar functions to the internet Extranet : an intranet or part of an intranet which can be accessed by certain external users by the internet.