3Types of Computers Mainframe Computers PC ( Personal Computer ) Networked ComputerLaptopPDA ( Personal Digital Assistant )
4Mainframe computer Description Capacity : very power full computers Are big , powerful , expensive computers used by most large organizationCapacity :very power full computersSpeedVery Fast in processing dataCosts :very expensiveUsersLarge companies including banks...
5( PC) Personal computer DescriptionIBM invented the pc since 1981Capacity :large hard diskSpeedFast normally measured in GHzCosts :Getting cheaper by dayUsersHome users , Doctors , Education …..
6Networked Computer Description Capacity : large hard disk Speed Allow you to connect two or more than one computer togetherCapacity :large hard diskSpeedFast normally measured in GHzCosts :A pc need inexpensive card to connect to networkUsersHome users , Doctors , Education , any one…..
7Laptop Description Capacity : Speed Costs : Small , Portable , Can run on batteries as well as main powerCapacity :Large hard disk, often less powerful than PC which is equivalent in priceSpeedFast normally measured in GHz – Speed specification are less than PC which is equivalent in priceCosts :Exceeds when compared with PCUsersBusiness users , People on the move , Educational user
8PDA ( Personal Digital Assistant ) DescriptionUse a special pen rather than keyboard, can store and retrieve informationCapacity :Much smaller than PCSpeedMuch slower than PCCosts :Exceeds when compared to PCUsers :Mostly Business Users
11System Unit The name given to Main PC box It Houses items like …. Mother BoardCPURAMCDFloppy Disk
12System (Mother ) BoardAll items of the system unit attached to Mother board , either directly or via cable
13CPU (Central Processing Unit ) IT is one of the most important components within ComputerIt is the brain within your ComputerIt performs most of the calculation within the computerIt determines How fast you Computer will runIt is measured by GHz2 GHz Pentium is much faster than 1GHz Pentium
15RAM ( Random Access Memory ) It’s where the operating system is loaded when you switch on your computerIt’s where your application are copied to when you start application (such as word processing )Volatile and changeableThe more RAM you Have installed in you Computer is betterIt is measured by MBThese days you will commonly find over 512 MB of Ram installed
16ROM - BIOS ( Read only Memory – Basic input out put system ) It is special chip held on your computers’ mother boardIt contains Software which makes your computer work with your operating systemIt is Non volatile, unchangeable
17Serial PortIt is socket located at the back of your computer which enable you to connect items to the computer , such as Modem
18Parallel PortIt is socket located at the back of your computer which enable you to connect items to the computer , such as Modem
19USB (Universal Serial Bus ) It is Relatively new item within the PCYou will see one or more USB Sockets at the back of Your computerIt enables you to Plug in devices such as Printer, Scanner, Digital camera .
28ScannerA scanner allows you to scan printed material and convert it into a file format which may be used within PC
29Web CamEver since it was invented , the web has become increasingly interactive .It allows you to communicate in two ways not just text communication but also sound and video
30Digital CameraA digital camera can be used in the same way of traditional camera but instead of storing images on rolls of films , the images are storing in memory housed within the camera ,this images can easily be transferred to your computer
31Output Device ….Output devices allow you to output information From the computerComputer monitorFlat screen monitorComputer presentation projection devicePrintersspeakers
32Computer monitorThe VDU ( Visual Display Unit ) is the computer screen used to output information.
33Flat screen monitorFlat screen computer monitor have become available , these take less size on the desk and use less energy than the traditional
34Computer presentation projection device It can be attached to your computer and it is useful to display presentations to group of people.
37Output / Input Device …. Some devices are both input / output devices Touch screen
38Storage Device Hard desk ( Internal – External ) Zip Driver Diskette CD deskDVD driverJaz DisksBack up tape
39Hard disk Internal Hard Disks Speed: Cost: Very fast! The speed of a hard disk is often measured by “RPM" speed, The smaller this number the slower the hard disk.Capacity:Enormous! Often in excess of 10 Gigabytes. A Gigabyte is equivalent to 1024 Megabytes.Cost:Getting cheaper by the day
40Hard Disks External Hard Disks Speed: Capacity: Cost: Normally slower than internal disks, but more expensive, offer the same performance as internal hard disks.Capacity:Same as internal disks.Cost:More expensive than internal disks.
41DVD Drives Speed: Capacity: Cost: Much faster than CD-ROM drives but not as fast as hard disks.Capacity:Up to 30 G bytes.Cost:Slightly higher than CD-ROM drives.
42CD-ROM (Compact Disc) Speed: Capacity: Much slower than hard disks. Around 650 Mbytes.
43Zip Disks Speed: Capacity: Slower than hard disks but ideal for backup.Capacity:100 or 250 Megabytes.
44Jaz Disks Speed: Capacity: Slower than hard disks but ideal for backup.Capacity:Around 2 Gigabytes (2048 Megabytes).
45Diskettes (Floppy Disks) It can be write protected to prevent data from changes or infection of viruses.Speed:Very slow!Capacity:Normally 1.44 Mbytes.Cost:Very cheap.
46Back up TapeUsed to archiving the files that are not needed
47Storage measurement Tera byte = 1024 Giga byte Giga byte = 1024 Mega byteMega byte = 1024 Kilo byteKilo byte =1024 ByteByte = 8 Bit
48SoftwareTypes of SoftwareOperating SystemApplication Program
49Format Pre formatted disk can be used immediately to store data. Unformatted disk need operating system data written to them before they can store files.Pre formatted disk can be used immediately to store data.Full formatting completely erase the previous contents of a disk.You can purchase preformatted disk.You can reformat a used floppy disk.
50Operating System DOS Windows The operating system is a special type of programs which is loaded automatically when you start your computerThere are number of different types of operating systemDOSWindowsUnix and LinuxMac/OS
51DOS IBM invented Pc Since 1981 And used DOS Operating system. This operating system was very basic.You had to be computer expert just to understand how to use computerIt was not user – friendly
52WindowsMicrosoft introduced windows which is more powerful than DOS and which is commonly used on PC today.There are numbers of different types of windowsThe main advantage of windows that it has a Graphical User Interface ( GUI )
53Graphical User Interface ( GUI ) It is part of operating system which display windows and drop down menusThe system using windows, icons to operate a computerIt enables you to drive your computer by using mouseAdvantageAll programs look similar and when switches from a program supplied by one manufacturer to different program supplied by another manufacturer , you will find the transition very easyBy GUI its easier to learn and use Application Program
54Unix & LinuxAre other examples of Operating Systems which may be run on PCs
55Other Types of computers , Such as Manufactured by Apple have a completely different operating System called Mac/OS .
56Application SoftwareAn application program is the type of program which you use when the operating system has been loaded.Can run more than one at the same time.Can be used to edit data type
57Create letters, Faxes, Memos Example ….Word ProcessorCreate letters, Faxes, MemosSpread Sheet ( Excel )Make financial projectsWith ChartsDatabase ( Access )Sort large amount of informationPresentation ( Power point )Crate overhead projection or slidesDesktop publishProducing a newspaper withcomplex page layoutAccounts payroll ( Sage )(Make financial projects )large Organizations
58Things to avoid Dust Drinking and eating over the key board Heat MoistureDon’t move the system while it switched onFollow the correct steps to shutdown your computerDon’t place object in the top of monitorDon’t place floppy disk near monitor . Monitor produce a strong electromagnetic
59System Cycle Most project work in cycle First step ( System analysis): Analyze the need of computer user.Second Step ( Design )Draw up the plans on how it can be implemented on a real.Third Step ( Programming )Convert the design to actual plan.Final Step ( Testing )Testing the software.