03_computer applicationsGOA105X 2022.pptx

Personal Computers or desktop computers are the most widely used of all types of computers.
They are more versatile than the PDAs
They are much cheaper than the mainframes
They allow networked to allow multi-user support
Recent desktops have a high processing power
They are widely used in homes, schools and business
They are divided into two categories, the desktop computer and the laptop. Desktop computers are designed to be used in a fixed location while the laptop is designed for mobility.

1. 03 Computers

2. What is a Computer? A computer is device with processing capability It can accept data (or input), process it, provide solutions (or output) and store the output in a hard drive. Computers perform the following four basic functions, which are: Input Processing Output/Display Storage

3. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.chtips.com%2Fcomputer-fundamentals%2Ffunctions-of-computer-system&psig=AOvVaw23F5rpt3BcLFQxcgxBJs5W&ust=1595884242609000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCICQ0pvq6-oCFQAAAAAdAAAAABAD

4. Types of Computers

5. Personal Digital Assistant (PDAs) PDAs are the smallest most portable hand held computers. They are small in size and have low processing power and storage capacity. They are not as versatile (flexible) as personal computers (PCs) but can actually be connected to a PC for information exchange. The PDA group include Pocket PCs, Palms and Smart Phones.

6. https://www.google.com/url?sa=i&url=https%3A%2F%2Fcsc2k17.wordpress.com%2F2017%2F11%2F22%2Fpda-personal-digital-assistant%2F&psig=AOvVaw2ur5os_EBGExN7ymHkj_G5&ust=1595885021869000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCKDAgo_t6-oCFQAAAAAdAAAAABAF

7. Personal Computer (PCs) Personal Computers or desktop computers are the most widely used of all types of computers. They are more versatile than the PDAs They are much cheaper than the mainframes They allow networked to allow multi-user support Recent desktops have a high processing power They are widely used in homes, schools and business They are divided into two categories, the desktop computer and the laptop. Desktop computers are designed to be used in a fixed location while the laptop is designed for mobility.

8. https://www.google.com/url?sa=i&url=https%3A%2F%2Fturbofuture.com%2Fcomputers%2FBuying-Your-First-Desktop-Computer&psig=AOvVaw3kRlI2VfP0F-01efcbCRBN&ust=1595885735197000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCOiAmefv6-oCFQAAAAAdAAAAABAG

9. https://www.google.com/url?sa=i&url=https%3A%2F%2Fstore.hp.com%2Fus%2Fen%2Ftech-takes%2F5-great-reasons-to-own-an-all-in-one-desktop-computer&psig=AOvVaw3kRlI2VfP0F-01efcbCRBN&ust=1595885735197000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCOiAmefv6-oCFQAAAAAdAAAAABAR

10. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.lenovo.com%2Fza%2Fen%2Flaptops%2Fideapad%2Fc%2FideaPad&psig=AOvVaw13IXMr3PgAxTUsJlnXRBOI&ust=1595886230333000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCPD7qtLx6-oCFQAAAAAdAAAAABAE

11. Mainframe Computers Mainframe computers are the largest and most expensive computers They are designed for large scale processing. They are mainly used by large organisations for critical applications. Scientists and researchers use them for complex computations and simulations. They are used for control system e.g. the one that in controlling ATM (automated teller machine) network. More than 100 people can use it at the same time They are generally more expensive than the other computer types. They can be used as network server on the internet

12. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.3nions.com%2Fdifference-between-personal-computers-and-mainframes%2F&psig=AOvVaw1IkVsCMu9n6xQXPNAMpVf3&ust=1595886837136000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCKjjtvfz6-oCFQAAAAAdAAAAABAD

13. Networked Computers Networked computers are computers that are connected together so that they can share data and resources (e.g. printers) and support communication and file transfers between their users. The smallest network consists of 2 computers connected to each other.

14. https://www.google.com/url?sa=i&url=https%3A%2F%2Fnetworkencyclopedia.com%2Fwhat-is-networking%2F&psig=AOvVaw3uOIwjsT1AUPu0fR1tmJne&ust=1595887455667000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCLicvZv26-oCFQAAAAAdAAAAABAD

15. Computer Hardware: CPU CPU stands for Central Processing Unit. It contains a functional unit (processor) that interpret and carry out instructions. It may be likened to Central Nervous System of a person. The purpose of the central processor is to retrieve instructions and the data required to process them, and perform the different required operations. Processor models were initially named for example for example 80286 or simply 286. Some examples of the processors are 386 sx , 386dx, 486DX2, 486DX4 or Pentium I, Pentium II, Pentium III, Pentium IV. We now also have the AMD K-6 Processors. The type of processors determines the speed and efficiency of the computer. Generally the higher the processor model number, the faster the processor. In general, processor size and speed increase incrementally e.g. i3, i5 and i7. An i7 is more powerful than the i3 processor.

16. Computer Hardware: CPU The speed of the processor is measured in Megahertz (MHz) which means million cycles or instructions every second. (now in Gigahertz) The speed of the computer is actually given by the Clock of the computer which sends timed electrical signals every second and provides the processor’s heartbeat. The processor is made up of two functional units and a set of workspaces that is Control Unit, Arithmetic Logic Unit (ALU) and Registers.

17. The Control Unit The control unit is responsible for supervising the operation of the processor. It performs the “fetch and execute job” that is retrieving instructions from memory and executing them accordingly. The control unit is driven by a clock pulse. The rate of the clock directly affects the processor speed and it is measured in Megahertz (MHz).

18. The Arithmetic Logic Unit (ALU) The ALU is responsible for all the mathematical operations. It receives data and instructions from the Control Unit and performs either Arithmetic operations (add, subtract, multiply and divide) or logic operations (e.g. making comparisons).

19. Input Devices Input devices send data and instructions to the computers. There are many input devices but the most common ones are the keyboard and the mouse. Keyboard Mouse Trackball Light pen Touch screen Modem Scanner Microphone Bar Code Reader Digital Camera

20. Keyboards This is a human tough input device, which means it needs the human hand to press the keys when entering data. It is mostly captures text data. There are four general areas of the keyboard. These are the function keys that are labelled from F1 to F12, the typewriter area in the QWERTY format; the numeric keypad located on the far right side of the keyboard and the cursor motion and control keys. To use the keyboard, just press and release the keys.

21. Mouse The mouse is used for all “ point and click ” operations. It is a powerful device in today’s graphical user interface type of programs. The mouse translates the movement of the hand to the movement of an arrow, called the mouse pointer, on the screen. The mouse usually has a ball underneath which rolls when the mouse is moved, and this ball cause two shafts to rotate. When the pointer is over an icon the mouse buttons can be clicked or double-clicked, or the mouse can be dragged to initiate an action. When the mouse is sticky, you can turn the ball towards the right side and open the lead to clean the mouse.

22. Trackball A trackball is commonly used instead of a mouse on laptop and notebook computers. The main part of these devices is a ball built into the keyboard. The ball has the same function as the ball into the bottom of a mouse. When you turn the ball the pointer moves.

23. Trackball https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.grainger.com%2Fproduct%2FKENSINGTON-Corded-Trackball-Mouse-6NWC3&psig=AOvVaw1b9okXrViF1U1W1WKgcy7f&ust=1595931769605000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCNiFyaKb7eoCFQAAAAAdAAAAABAE

24. Scanner This is used to capture text and graphical or image data. There are two types of scanners, the hand and the table or flatbed scanner. When you want to copy a printed picture into a computer you need a scanner to capture it. The hand scanner is pulled over the image manually, whereas the table scanner is like a photocopier, automatically pulls the sensors over the image.

25. Scanner https://www.google.com/url?sa=i&url=https%3A%2F%2Fimagescience.com.au%2Fproducts%2Fepson-perfection-v600-scanner&psig=AOvVaw0w0vwUTLadOrukyPdN88YT&ust=1595931904074000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCLCau-Kb7eoCFQAAAAAdAAAAABAG

26. Light Pen This is a device the size of a normal pen with a light at its end. This light pen is connected to the computer by code. The used touches the point of the light pen on the screen of a special pad then makes writing or drawing motions. Artists and designers mostly use this device.

27. Light Pen https://www.google.com/url?sa=i&url=http%3A%2F%2Fshaniqueeportfolio.weebly.com%2Flight-pen.html&psig=AOvVaw06f_hD8u1MzvYHjZHcsBVk&ust=1595932076571000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCOjSk7-c7eoCFQAAAAAdAAAAABAQ

28. Touch Pad This allows the user to sketch a design. It is a flat pad that user can write on using a pen like structure known as Stylus. All movements made on the pad by the stylus are translated into writing or drawings on the screen, because the pad is sensitive to the position of the stylus and the stylus is sensitive to the pressure applied by the user.

29. Touch Pad https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.tech-recipes.com%2Frx%2F66163%2Fhow-to-install-precision-touchpad-drivers-on-windows-10%2F&psig=AOvVaw3lgO9lhtR3f9XUyTY1qxGu&ust=1595932202723000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCMDj3fCc7eoCFQAAAAAdAAAAABAE

30. Touch Screen This device work similar way to the light pen. Signals are sent whenever the user touches any position on the screen to execute a particular instruction. A finger or pen can be used with map kiosks in shopping centres and pen based computers respectively. Touch screens are easy to use because of this we call them user friendly. They usually found in public areas. Some ATMs use a touch screen.

31. Touch Screen https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.touchscreenguru.com%2Fstore%2F55-uhd-multi-touch-pcap-lcd-touch-screen-monitor&psig=AOvVaw0_vsfPRS0ICTvTCTh3zrBu&ust=1595932295064000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCNjUgp2d7eoCFQAAAAAdAAAAABAF

32. Output Devices These are devices that display or output work which has been done by the computer in a form readable and understandable to the user. These include the following: Monitor Printer Plotter Speakers

33. Monitor/Display This is also called the screen or VDU (Visual Display Unit) It is the main way of getting the processed data out of the computer. Monitors come in different shapes and sizes. The most common size is the 14 inch, 15 inch and 17 inch and the size is measured diagonally. Although they come in different capabilities in terms of colour output their function is still the same – to display information to the user. NOTE: Switching on and off your monitor will not affect your information. Whenever you switch off you computer remember to switch off your monitor. The CPU can run continuously for days because it has got an inbuilt fan but the monitor need to be switched off because of the absence of the inbuilt fan and it can become hot after some time.

34. Types of Monitors Liquid Crystal Display (LCDs): This is a type of screen that does not consume as much power as the normal PC (Cathode Ray Tube) monitor. They are used in laptop computers. Some of digital watches, cell phones and calculators use this type of displays. Light Emitting Diode (LEDs): These are small electronic components that emit light when a voltage is passed though them. They are 3-10mm in diameter.

35. Printers Printers produce “hard copies” printed on permanent material (paper). It is called hard copy because it is tangible and cannot be easily changed. There are two categories of printers, impact and non-impact printers. The Dot Matrix is an example of a impact printer because it uses tiny dots to produce letters and graphics. They make a lot of noise and are quite slow. Some examples of Dot matrix printers are the Epson LX300, Epson LX780 and the Citizen Prodot 24. https://raru.co.za/electronics/6850513-epson-fx-890ii-dot-matrix-printer-impact-dot

36. Printers Ink Jet printers are an example of non-impact printer since they use nozzles to spray characters on the pages. They are between the dot matrix and laser printers in terms of speed and quality. Some examples are Cannon BJC 620, HP610C HP590C, etc https://in.pcmag.com/printers/95856/the-best-inkjet-printers-for-2020

37. Printers Laser Jet Printers use the principle of photocopies and use a laser beam to print characters on a page. They are faster and more expensive. They are also an example of non-impact printers. High quality text and graphics are produced. Some examples are HP LaserJet 1100, HP LaserJet 2100. https://raru.co.za/electronics/7823555-hp-managed-e60155dn-laserjet-printer

38. Printers Plotters - Plotters are used in the scientific and engineering sectors for printing building plans, machines and machines parts. Plotters can print up to A0 paper size. Plotter use precision motors controlled by a computers. These motors move an arm across the paper in the X direction and a pen unit up and down in the Y axis direction whilst an electromagnetic lifts and drops the pen into the paper, by so doing drawing or plotting and object according to instructions. https://www.quora.com/What-are-plotters-What-functions-do-they-have

39. Speakers Computers with sound cards are able to translate digital sound into audible signals via speakers. http://ipsnews.net/business/2020/06/06/fluance-ai60-bluetooth-speaker-review-large-and-in-charge/

40. Storage Devices Keeping information for later use, and it is one of the most important tasks when one is operating a computer. It is therefore necessary that one understands the different types of storages devices. These devices store information and are part of secondary memory: Hard Disks Floppy Disks CD ROM ZP Disk Magnetic Tapes Flash Drive External hard Drive

41. Hard Disk/Hard Drive The hard drive is the most common form of secondary storage. The hard disk is found in the Central Processing Unit (CPU) and cannot be removed by the user. It is usually known as the drive as the Drive C and when partitioned the other partition may be called drive D. Hard disks differs in size with common sizes being 500Gig and 1 Terrabyte for laptops. The hard disks holds the operating systems, the basic software your computer requires for it to be functional. It also holds other program applications such as your word processing programs. Data and information are stored magnetically on the surface of a flat circular plate that rotates at a very high speed of about 60 revolutions per minute.

42. Hard Disk/Hard Drive The hard disk also contains the disk heads, which read and write information onto a disk. They are a type of direct access storage device since each sector containing data can be addressed directly and because of this access is extremely fast. A PC may have more than one hard disk. What is the difference between an external and internal hard drive? The internal hard drive sits within the computer case or box whereas an external drive sits outside the computer case and can be detached from the computer. It can be moved to another computer and attached – therefore allowing the use of core and library material on any number of computers.

43. https://za.rs-online.com/web/p/hard-drives/1828700/

44. Floppy/Stiff Disks (No longer in use) These are the removable part of secondary storage. They are used with floppy drives and there are two types of floppy disks, the 3.5-inch and the 5.25-inch. The 5.25 –inch disk is virtually obsolete and new computers are being manufactures without this drive. The 3.5-inch diskette is more robust, physical smaller and can hold more information than the 5,23-inch floppy Advantages of Floppy Diskettes They are cheaper than hard disks and CD-ROMs They are portable hence used to transfer data or information from one computer to another They offer direct access and they are faster than magnetic tapes Disadvantages of Floppy Diskettes They are prone to virus They are difficult to handle The can be easily be corrupted They have a relatively short life span They hold relatively smaller amount of data They are not always 100% efficient

45. https://www.quora.com/Will-floppy-disks-make-a-return-in-2020

46. Magnetics Tapes These are same as those used radios or tape recorders. Data or information is stored on tape in a sequential way in blocks separated by interblock gaps. The tape drives have magnetic heads, which read or write information on to the tape as it moves. Usually the tape drive is external and connected to the computers by a cable. Advantages of using magnetic tapes They are relatively cheap Used for back-up purposes and can take a copy of a hard disk They are reusable i.e. can be overwritten Can be used in any environment Easier to handle than multiple floppy disks when backing up large files Disadvantages of Using Magnetic Tapes Data access is very slow since it is sequential It is expensive to buy the tape drive

47. https://www.iasa-web.org/magnetic-tape-alert-project

48. Compact Disks These are the common means of distributing software to PCs. They look exactly like musical CD’s that are played on your radio. They store a large amount of information up to 650MB in the form of text, sound, still pictures, animation and video clips. A laser beam reads the information. CDs can be found in four different forms, that is the CD-ROMS, CD-Rs, CD-RWs and finally the DVDs. CD ROMs:These letters stands for Compact Disk – Read Only Memory that means you can only read but cannot change anything either by deleting or adding new information. Although it’s a storage device it cannot be considered to be a backing store since the user cannot write onto it. They are to distribute programs such as encyclopaedias , dictionaries, multi-media, programs, educational programs and games. CD-Rs:These are blank CDs that the user can write on, once only using a CD write which can be either external or internal.

49. Compact Disks CD-RWs: These are re-writable CDs, which means the user can read and write many times as if using a hard disk. DVDs:Digital Video Disks use the same principle as CD-ROMS but store more information. They are more information on both sides and they can take up to 17Giga Bytes. DVDs are becoming widely used for distribution of films and video materials. To play a DVD you must have a DVD Drive or Player (which is also able to play CD-ROMs) Zip or Flip Disks: These are like floppy diskettes by with an external zip drive. They are used for data back-up and can take up to 120MB, Their advantage is that they can be disconnected or store in different site from the computer, so they are ideal for remote sites back-ups.

50. https://edition.cnn.com/2012/09/28/tech/innovation/compact-disc-turns-30/index.html

51. The End