2What are computers?Computers are electronic devices that can follow instructions to accept input, process the input and then produce information. It is a machine that manipulates data according to a set of instructions.
15Hardware Organization CPUmemoryhard driveغير مطلوبة فقط للفهم
16Mother-Board (or Main Board) غير مطلوبة فقط للفهمغير مطلوبة فقط للفهمCPURAMROM
17Hardware Organization CPUmemorymotherboardhard driveغير مطلوبة فقط للفهم
18Central Processing Unit (CPU) A specific chip or the processora CPU's performance is determined by the rest of the computers circuitry and chips.The Central Processing Unit (CPU) performs the actual processing of dataThe speed (clock speed) of CPU measured by Hertz (MHz)
19The CPU consists of : Control Unit (CU) Arithmetic and Logical Unit (ALU)Some Registers
20Central Processing Unit (CPU) This is CPU Only:Central Processing Unit (CPU)Control Unit (CU)Arithmetic LogicUnit (ALU)Registers
21coordinates all activities of the computer by: The Control Unit (CU) :coordinates all activities of the computer by:Determining which operations to perform and in what order to carry them out.The CU transmits coordinating control signals to other computer components.
22consists of electronic circuitry to perform: The ALU :consists of electronic circuitry to perform:Arithmetic operations (addition, subtraction, multiplication and division)Logical operations (and, or, not, …) and to make some comparisons (less-than, equal, … etc.)
23Hardware Organization CPUmemorymotherboardhard driveغير مطلوبة فقط للفهم
24Primary MemoryMemory (fast, expensive, short-term memory): Enables a computer to store, at least temporarily, data, programs, and intermediate results.Two general parts:RAMROM
25RAM (Main Memory) its a primary storage or random access memory (RAM). it temporarily holds data and programs for use during processing (volatile)Any information stored in RAM is lost when the computer is turned off.RAM is the memory that the computer uses to temporarily store the information as it is being processed. The more information being processed the more RAM the computer needs.RAM consists of locations or cells. Each cell has a unique address which distinguishes it from other cells.
28ROM: Read Only Memory ROM is part of memory Programmed at manufacturing timeIts contents cannot be changed by usersIt is a permanent storeQ: Mention some examples of ROM?A: (PROM & EPROM )
29Other Kind of Memory PROM: Programmable Read Only Memory. EPROM: Erasable Programmable Read Only MemoryCache MemoryRegisters: not part of the main memory.Q : Registers are part of “ …… ” ?
30Secondary StorageStores data and programs permanently: its retained after the power is turned offExamplesHard Drive (Hard Disk)Located outside the CPU, but most often contained in the system cabinetFloppy DiskOptical Laser DiscsCD-ROM, CD-RW, and DVD
32Common Secondary Media DiskettesData represented as magnetic spots on removable flexible plastic disksMost common size is 3 1/2 inches, in a rigid plastic caseDisk drive holds the diskette, reads or retrieves the data and writes or stores data
33Common Secondary Media Hard driveData is represented magnetically as with diskettesNormally more than one rigid platter in a sealed unitThese disks are not removableSignificantly more capacity and faster operating than diskettes
35Hardware Organization CPUmemorymotherboardhard driveغير مطلوبة فقط للفهم
36Common Secondary Media Optical Laser DiscsCD ROM & DVD’sData is represented as pits and landsSome kinds are read only (CD-ROM) and some Kinds are rewritable (CD-RW)Significantly more capacity and faster operating than diskettesDVD: Digital Video Disk
37Approximate printed 8.5 x 11 inch pages Common Secondary MediaApproximate printed 8.5 x 11 inch pagesAmount of storageDisk size180 pages360 Kb5.25 low density360 pages720 Kb3.5 low density600 pages1.2 Mb5.25 high density720 pages1.44 Mb3.5 high densitya small library700 MBCDa feature length movie8.5 GBDVD
38Common Secondary Media tapesPanasonic's LS inch diskettesIomega's Zip & Jazz disksVCR tape (Video Cassette Recorder )Flash USB disksMMC (Multi Media Card )SD
39The benefits of secondary storage can be summarized as follows: Capacity. Organizations may store the equivalent of a roomful of data on sets of disks that take up less spaceReliability. Data in secondary storage is basically safe, since secondary storage is physically reliable.
40Convenience. With the help of a computer, authorized people can locate and access data quickly. Cost. It is less expensive to store data on tape or disk (the principal means of secondary storage) than to buy and house filing cabinets.
41Hardware Organization CPUmemoryhard driveغير مطلوبة فقط للفهمOutput …
42CPUOutput DevicesPieces of equipment that translate the processed information from the CPU into a form that humans can understand.Processedinformation
43Output Devices Monitors Printers Dot matrix printersInk jet printersLaser printersSound Blasters (Sound Card By Creative Lab)Controlling other devices
44Software The instructions that tell the computer what to do Application Software - helps end-users perform general purpose tasksSystem Software - enables application software to interact with the computer
45System Software System Software Operating System The most important is theOperating SystemExamples of operating systems:Windows XP, DOS, Apple, UNIX
46System SoftwareThe software that controls everything that happens in a computer.Background software, manages the computer’s internal resourcesResources examples : CPU, RAM , I/O devices, …
47Among other things, the operating system: All hardware and software are under the control of the operating system.Among other things, the operating system:Determines how valuable RAM is allotted to programs.Performs tasks related to file management.Sets priorities for handling tasks.Manages the flow of instructions, data and information to and from the processor (CPU).
48Examples of Microcomputer Operating System Software DOS - original standard for IBM compatiblesWindows - a graphical operating environmentWindows VISTA, XP, millennium, 2000, 98, and 95Continue …
49Examples of Microcomputer Operating System Software Cont. Windows NT - for powerful workstations & networksOS/2 - competitor to Windows 2000Macintosh Operating SystemUnix - originally for minicomputers, now used on microcomputers and Internet serversQuestion: List some examples of operating systems ?
50Application Software Packaged Custom Packaged - “off the shelf”, pre-written programs ( General purpose)Custom - written for an organization’s specific purpose (Special purpose)
51Application Software – Basic Tools Word processors– example: Microsoft wordSpreadsheets-- example: Microsoft ExcelDatabase managers-- example: Microsoft AccessGraphics-- example: PhotoshopSpreadsheets: Computer software that allows the user to enter columns and rows of numbers in a accounting book like format.
52Units of Measurements Bit (Binary Digit)(takes two values: 1 or 0) Byte = 8 bitsKB (Kilo-byte) = 1024 bytesMB (mega-byte) = 1024 KBGB (giga-byte) = 1024 MBTB (Tera-byte) = 1024 GBRemark: 1024=210
53Four Kinds of Computers Microcomputers2. Minicomputers3. Mainframe computers4. Supercomputers
54Comparison between the previous kinds of computers may made based on : PriceProcessing SpeedStorage CapacityPowerfulSingle-user or Multi-userSupporting hundreds (or thousands) of users simultaneouslyComputer SizeCompanies size…etc.
55Microcomputer =>Personal Computer => PC There are 3 types of the Microcomputers :LaptopDesktopWorkstation
56Personal Computer: A small, single-user computer based on a microprocessor. 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.
57Minicomputer, Mainframe, and Supercomputer Minicomputer: A multi-user computer capable of supporting up to hundreds of users simultaneously.Mainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second.
58Desktop Computer Small enough for a desktop, but not easily portable Personal computers (PC’s) run general purpose software and are employed by a wide spectrum of users
59Desktop Computers Cont. Workstations are powerful machines, running more advanced software, for technical, scientific, or data-intensive tasksThese distinctions, however, are blurring
60Portable ComputersEasily transported from one place to another
61Portable Computers Four categories Laptops Notebooks Sub-notebooks Personal Digital Assistants (PDA)Q: list all portable computer categories?
70Characteristics of Computers 1- Store a large amount of data and information for a long period of time.2- process data and information in high accuracy level .3- Speed in processing data information.4- Sharing of information / network.
71Understanding the difference between Data, Information and Knowledge: ComputerDataInformationKnowledge
72Data: is the name given to basic facts such as names and numbers. Information: is data that has been converted into a more useful or intelligible form.Knowledge: arrangement of information and classifying information of the same type or the same topic.
73DataData: are details of various types of transactions and details relating to specific situations, which are input to a data processing system (e.g. computer) for processing in a prescribed way.Examples of data relating to students are student-number, student-name and grades.
76Information Information: the result of processing data. Information: Must serve a useful purposeMust be of an acceptable level of accuracyMust be available at the right timeMust be relevant to the enterprise, person, … etc.
77KnowledgePutting a number of information with the same type or same topic would be a knowledge.
78Processing data produces information, and processing information produces knowledge.
80Computer VirusesA computer virus are small software programs that are designed to spread from one computer to another and to interfere with computer operation.A virus might corrupt or delete data on your computer, use your program to spread itself to other computers, or even erase everything on your hard disk.
81Examples of Viruses Win32/Conficker INF/Autorun Win32/PSW.OnLineGames n32/Agent
82Viruses and Virus Protection A virus programInfects programs, documents, databases and more …It is man-madeIt can hide and reproduceIt can lay dormant (inactive) and then activateAnti-virus programs can help
83Types of Computer Viruses Macro VirusesA macro virus, often scripted into common application programs such as Word or Excel, is spread by infecting documents.Network Virusesrapidly spreads through a Local Network Area (LAN), and sometimes throughout the internet.•Trojan HorsesThe Trojan virus once on your computer, doesn't reproduce, but instead makes your computer susceptible to malicious intruders by allowing them to access and read your files. Making this type of virus extremely dangerous to your computer's security and your personal privacy.
84Types of Computer Viruses Logic Bombsa piece of code that are inputted into a software system. When a certain and specific condition is met, such as clicking on an internet browser or opening a particular file, the logic bomb virus is set off.Companion Virusestakes advantage of MS-DOS. This virus creates a new file with typically the .COM extensions, but sometimes the .EXD extension as well.
85Types of Computer Viruses Boot Sector Virusesgenerally hide in the boot sector, either in the bootable disk or the hard drive. Unlike most viruses, this virus does not harm the files in the hard disk, but harm the hard disk itself.Multipartite Virusesspreaded through infected media and usually hides in the memory. Gradually, the virus moves to the boot sector of the hard drive and infects executable files on the hard drive and later across the computer system.
86Sources of Computer Viruses Three primary sourcesThe InternetVia downloads and exchangesDiskettesExchanging disksComputer networksCan spread from one network to another
87How do you know if you have a virus? Lack of storage capabilityDecrease in the speed of executing programsUnexpected error messagesHalting the system
88Virus ProtectionThe software package distributed with new PCs always includes an antiviral program. The best way to cope with viruses is to recognize their existence and use an antiviral, or antivirus program.
89Some tips that will help minimize your vulnerability to viruses: Delete s from unknown or suspicious, untrustworthy (unreliable) sources, especially those with files attached to an .Never open a file attached to an unless you know what it is, even if it appears to come from a friend.Download files from the Internet only from legitimate and reputable sources.Update your antivirus software at least every two weeks as over 200 viruses are discovered each month.Backup your files periodicallyTraditionally virus protection has been at the PC or client level. However, this may change as companies look to network and Internet service providers for more services.