Computer

1. Computer A computer is a device that performs computations. There are several types of computers: - Main Frame/Super Computers - Desktop or Personal Computers (PC) - Notebook/Laptop Computers All computers have one or more interface(s), so that they can interact with users (Monitor, keyboard, mouse). In addition they have internal components that allow them to perform tasks/computations (CPU, Hard Drive, and memory (Random Access Memory [RAM])

2. Computer Components A typical computer system has the following elements: Input - The PC takes data from the user via the keyboard or a file. Processing - The PC processes the data based on a pre-defined algorithm. Output - The results of the computation, is placed in the output defined (the monitor, printer, a file..etc.) Storage -- Permanent (ROM, Hard/Floppy drive, USB drive) -- Temporary (RAM)

3. Parts Of A DeskTop Computer

4. Laptop/Notebook Computers Windows 7 Laptop Apple Macintosh Laptop Notebook Computer

5. The Personal Computer (PC) The ‘Apple Macintosh’ (Mac) computer was introduced in 1976 by the ‘Apple Corporation’ The ‘IBM’ computer (IBM PC) was introduced in 1981 by ‘IBM Corporation’. Both computers were intended for ‘home’ use and were classified as a ‘Personal Computer’ (PC). A computer system is divided into two main categories: Hardware Software

6. PC Software Programs that are used by the PC to perform all of it’s operations are called ‘Software’. There are two types of PC software: Operating System Software Application Software

7. PC Software Operating System (OS) Software: The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

8. PC Software Operating System (OS) Software:

9. PC Software Application Software: Operating systems provide a software platform on top of which other programs, called applicationprograms, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux.

10. PC Software Application Software (cont’d): As a command-line user, you normally interact with the operating system through a set of commands. For example, the ‘Disk Operating System (DOS)’ contains commands such as ‘COPY’ and ‘RENAME’ for copying files and changing the names of files, respectively. The commands are accepted and executed by a part of the operating system called the command processor or command line interpreter. Graphical User Interfaces(GUI) allow you to enter commands by pointing and clicking at objects that appear on the screen.

11. Buying a PC The decision to buy a PC is influenced by many factors: If the PC is used exclusively at home, buy a desktop PC. A laptop (portable) computer can be used for school and home. Superior graphics can be obtained by using a MAC Whatever your choice in PC; buy as much RAM as you can afford (4G Bytes is ideal)

12. IBM vs. Apple Macintosh (MAC) Positive vs. Negative Aspects(Pros and Cons) IBM compatible PC’s are generally less expensive. There are more programs available for IBM PC’s. The majority of home users and businesses use ‘Windows-based’ PC’s More flexibility to move files from one PC to another in the Windows environment. IBM compatible PC’s are more susceptible to virus attacks. The MAC PC is built on the ‘Unix’ operating system, which is more stable and less prone to virus attacks. The MAC PC is less likely to ‘hang’. All ‘Windows’ operating systems have this tendency.

13. Communication Devices & Connections All PC’S currently manufacturedare ‘Internet Ready’. Communication to the internet is done using the following: Dial-up Modems (slow connection) DSL/Cable Modems Satellite Dishes Wireless connectivity

14. Your Computer Satellite Dish & Modem Connecting to the Internet - Satellite Satellite ISP

15. Your Computer DSL/Cable Modem Connecting to the Internet – DSL/Cable ISP

16. Blue Tooth Adapter for the PC Your Computer Connecting to other devices – Blue Tooth Cell Phone

17. Keyboard and Mouse Keyboard Layout: ▪ Function Keys: Keys labeled F1 thru’ F12 Used by applications programs for specialized tasks ▪ Arrow keys, Page Up, Page Down, Home, End Also known as cursor keys. ▪ Numeric Keypad. Activated/Decativated by pressing ‘Num Lock’ key.

18. Keyboard ▪ Shift Ctrl and Alt Keys: Used to generate more functions in conjunction with the function keys ▪ Esc key: Use to back out of a current screen or action. ▪ Windows Logo Key: Performs the same function as clicking the ‘Start’ button on the task bar.

19. Mouse ▪ The first mouse used was designed with a ‘track ball’ to indicate the position of the mouse pointer. This type of mouse had to be cleaned since the ball would pick up dust and dirt from it’s ‘rolling’ surface. ▪ The newer mouse is called an ‘IntelliMouse’ that is an optical mouse. An optical mouse uses laser technology, and does not need to be cleaned.

20. Monitors ▪ The monitor allows you to see what you are entering via the keyboard; the monitor also displays the contents of a file, or displays the contents of a web page. ▪ Older monitors used a vacuum tube to display information. Most new monitors are made up of a ‘Liquid Crystal Display’ (LCD). These monitors are also called ‘flat-screen’ monitors (they are physically thin) and uses less power than the old monitors.

21. Monitors (Resolution) The display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. In digital imaging, a pixel, (picture element) is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled. Each pixel has its own address. The address of a pixel corresponds to its coordinates.

22. Printers The term inkjet printer is very descriptive of the process at work -- these printers put an image on paper using tiny jets of ink. The term laser printer, on the other hand, is a bit more mysterious -- how can a laser beam, a highly focused beam of light, write letters and draw pictures on paper? The laser jet printer fuses toner onto paper to produce a smudge-free permanent reproduction of the page(s) in your document. Toner is an electrically-charged powder with two main ingredients: pigment and plastic.

23. Printers Toner Basics The role of the pigment is fairly obvious -- it provides the coloring (black, in a monochrome printer) that fills in the text and images. This pigment is blended into plastic particles, so the toner will melt when it passes through the heat of the fuser. This quality gives toner a number of advantages over liquid ink. Chiefly, it firmly binds to the fibers in almost any type of paper, which means the text won't smudge or bleed easily.

24. Printers (Inkjet vs. Laser) Positive vs. Negative Aspects(Pros and Cons) Inkjet printers are generally less expensive. Inkjet cartridges are expensive. A color printer uses two cartridges (black and color) Documents printed by an inkjet printer smudge easily. The free printer bundled with your new PC purchase will be a cheap printer. Documents printed by a laser printer do not smudge. Cartridges for a laser printer are less expensive, over the long term, because they use toner, not ink. The resolution of a laser printer is better than an inkjet printer.

25. Printers The Controller: The Conversation Before a laser printer can do anything else, it needs to receive the page data and figure out how it's going to put everything on the paper. This is the job of the printer controller. The printer controller is the laser printer's main onboard computer. It talks to the host computer (for example, your PC) through a communications port, such as a parallel port or USB port. At the start of the printing job, the laser printer establishes with the host computer how they will exchange data. The controller may have to start and stop the host computer periodically to process the information it has received.

26. Printers Older laser printers uses a few different types of communications ports.

27. Printers Newer laser printers uses the USB or Ethernet ports, and/or has a Wireless interface . USB Ports

28. Printers Ethernet port – Generally used by a network printer.

29. Wireless Printers Wireless printers are a recent addition to the world of shared resources; these printers connect to an existing wireless network. All PC’s that are allowed to join the wireless network can use the resources of the printer.

30. All-in-one Printers These type of printers have the capability to do the following: - Print - Copy - Fax - Scan

31. Scanners A printer produces a paper-copy of a file. A scanner does the opposite, it takes a paper-copy with information and converts it into a file. The file produced by the scanner is an ‘image’ file. In order to convert ‘image’ files to text files, requires the use of ‘Optical character recognition’ (OCR) software.

32. CD ROM/DVD A CD-ROM (Compact Disk Read Only Memory) is a drive which reads aluminum-coated round plastic discs. Invented in the United States in 1972, the CD-ROM standard was officially introduced in 1982 when Philips and Sony agreed on the 4.72-inch size format we now use today.

33. CD ROM/DVD

34. CD ROM/DVD The CD-ROM diskettes are 12 x 12 cm with a width of .1cm, as shown in the above picture. The disc is made of a polycarbonate wafer and is coated with a metallic film, usually an aluminum alloy. This aluminum film is the portion of the disc that the CD-ROM drive reads for information. The aluminum film (strata) is then covered by a plastic polycarbonate coating that protects the underlying data. A label will usually be placed on the top of the disc and data is read from the bottom of the CD.

35. Other CD Technologies CD-R - (CD Recordable) Drive which you are able to write to once. Once the drive is written to, it cannot be erased. CD-RW - (CD ReWritable) drive which is a popular alternative to the CD-R drive. CD-RW has the capability of being written to at least one thousand times.

36. CD-ROM INTERFACES SCSI (Small Computer System Interface) – These require a SCSI Host adapter card connected into the system. These cards may be ISA, VLB or even PCI bus cards. It is highly recommended to get a card that matches the CD-ROM drive as some of the earlier drives had proprietary SCSI interfaces. Otherwise, a SCSI-2 card is recommended.

37. CD-ROM INTERFACES IDE (Integrated Device Electronics) - These CD-ROM drives connect to an IDE port on the motherboard or hard drive interface card. Usually, the IDE controller on the hard drive is set as master and the CD-ROM drive is set to slave. IDE is commonly used for CD-ROMs in standard computers today.

38. CD-ROM INTERFACES USB - port CD-ROM drives come with special drivers to help communicate through a PC system's USB port. The transfer rate tends to be slower than other interfacing methods. Biggest advantage is the portability between systems including notebooks.

39. CD-ROM INTERFACES PCMCIA (PC Card) - Interface now exists for connecting an external CD-ROM drive through the system's PCMCIA port. This is good for portability and provides faster access than the Parallel port would. Personal Computer Memory Card International Association (PCMCIA) 

40. CD-ROM INTERFACES PCMCIA (Laptop/Notebook - Interface Card)

41. Other CD Technologies DVD - (Digital Versatile Disc) New standard released in 1995 which originally was called Digital Video Disc and later changed to Digital Versatile Disc. DVD offers an initial storage capacity of 4.7GB (of digital information on a single-sided, single-layer disc the same diameter and thickness of a current CD-ROM. The newer DVD uses Blu-Ray technology; which has between 17 and 20GB of storage, using a double-sided format.

42. CD ROM/DVD

43. CD ROM/DVD A view of a CD-ROM drive's disassembled laser system.

44. FLASH DRIVES Flash drives have replaced the ‘floppy disk’ as a portable storage device. They are small and light-weight and can hold between 256 MB to 128 GB of data. A flash drive is a special ROM chip; an ‘Electrically Erasable Programmable ROM’ (EEPROM).