Introduction to Computers

1. Introduction to Computers An overview of your personal computer

2. FS104 Computer Applications • Office hours for Sharon Kaitner, M.Ed. are at 12 noon on Tuesdays, room 010.

3. What makes up a computer? • Input devices • Output devices • Graphical User Interface (gui) • Memory • Storage

4. Input devices Output devices • Graphical User Interface (gui) What makes up a computer? Memory and Storage

5. What is a computer? • A computer is a collection of electronic devices that function together as a system.

6. Speakers • Modem • Microphone • RAM • CPU • Keyboard • Mouse • CD-ROM Drive • Diskette Drive • Hard Drive • Printer • Ports • Monitor • Expansion Board

7. INPUT DEVICES • Microphone • Keyboard • Mouse • Pc video camera • Scanners • Any hardware component that allows you to enter data, programs, commands, and user responses into a computer.

8. Output Devices • Speakers • Printer • Monitor

9. Storage • CD/DVD Drive • Diskette drive • Hard Disk Drive • System Unit (processor, memory, and storage) • RAM (random access memory)

10. Communications • Modem – this one is an external modem, mostly extinct for the favored DSL or Cable connection. Minimally, now internally located.

11. Through input devices, we enter data. Storage devices hold instructions to transfer data to memory. We then process the information via output devices.

12. The computer’s processor is usually called the CPU or Central Processing Unit. Here lies the control unit and the Arithmetic Logic Unit (ALU). The control unit interprets and executes instructions in memory and the ALU performs calculations on the data in memory. Any resulting information is then stored in memory for future access.

13. The CPU contains 4)RAM, 5)CPU, 8)CD-ROM Drive, 9)Diskette Drive, 10)Hard Drive, 12)Ports and 14)Expansion Board(s).

14. The Computer’s Internal Clock • Every microcomputer has a system clock, but not to tell time. • Like a watch, the clock is driven by a piece of quartz crystal. • When electricity is applied, the crystal vibrates millions of times per second, a rate that never changes.

15. The Computer’s Internal Clock • The speed of the vibration is determined by the thickness of the crystal. The computer uses these vibrations to time its processing operations.

16. The Computer’s Internal Clock • Over the years, clock speeds have increased steadily. For example, the first PC operated at 4.77 megahertz. • Hertz is a measure of cycles per second. One cycle means the time it takes to turn a transistor off and back on. Megahertz (MHz) means “millions of cycles per second.”

17. The Computer’s Internal Clock • The first PC was 4.77 MHz • Mid to late 1990’s, processing units were about 133 MHz. Megahertz means “millions of cycles per second.”

18. The Computer’s Internal Clock • My current CPU is running at 3.00GHz, or gigahertz. • The gigahertz, abbreviated GHz, is a unit of alternating current (AC) or electromagnetic (EM) wave frequency equal to one thousand million hertz (1,000,000,000 Hz).

19. Memory, also called random access memory or RAM, consists of electronic components that store instructions waiting to be executed. The motherboard, sometimes called a system board, is the main circuit board in the computer. Memory is measured in kilobytes (K or KB) or megabytes (M or MB). A byte is one character. A MB is approximately one million bytes, or memory locations.

20. Storage Devices • Floppy disks, or diskette, holds 1.44 megabytes of data (or 1,474,500 characters.) • Zip disks store 750 MB of data • Hard Disks consists of one or more rigid discs that are coated with material that allows data to be recorded magnetically. Storage capacity varies from one billion characters to more than 200 billion characters. One billion bytes are called a gigabyte (GB). Typical disk sizes ranges from 40 GB to 200 GB. • Optical discs are CD and DVD’s. A CD can hold 650 MB to 1 GB of data, which is 450 to 700 times more than a 3.5 inch floppy disk. A DVD can hold 4.7 GB to 17 GB – more than enough to hold a telephone book with every single resident of the USA! • A tape is primarily used for long-term storage and backup. • Miniature storage media, often used with PDAs, digital cameras, music players and smart phones, are rewritable and have no moving parts.

21. Communication devices • A communications device is a hardware component that enables a computer to send information to and from one or more computers. A widely used form is the modem. • Communication itself occurs over transmission media such as cables, telephone lines, cellular media, radio networks and satellites.

22. Computer Software • Software is what allows your computer to do something and makes it valuable to you • Software can be categorized into two types: system software and application software

23. System Software • System software are the programs that control your computer. • An important part of system software is a set of programs called the operating system. • The operating system tells the computer how to perform: store, load and execute. It’s stored in the computer’s memory. • The graphical user interface (gui) provides visual cues to help the user.

24. Application Software • Consists of programs that tell a computer how to produce information. This covers everything from Microsoft Word to computer games to tax preparation to authoring software…and beyond!

25. When there is a collection of computers and devices, such as printers, connected via communications media and devices (cables, telephone lines, modems, etc.), it is called a network. Computers are networked so they can share resources. What kind of resources are shared?

26. Computer and you • Computers and the Internet have significantly changed the way we live. • Name ways in which we have become dependent on technology.