Course ILT Basics of information technology Unit objectives Define “information technology” (IT), distinguish between hardware and software, and identify types of computers Identify the parts of a computer and the factors that influence computer performance Differentiate between application and operating system software, and describe the software development process Differentiate between LANs and WANs, and describe the Internet and intranets

Course ILT Topic A Topic A: Overview of information technology Topic B: Hardware and storage devices Topic C: Software Topic D: Networks

Course ILT Hardware devices The physical devices that make up a computer system Examples of hardware: –Monitor –Mouse –Keyboard –Central processing unit (CPU)

Course ILT Software The instructions that make a computer work Can be stored on a computer’s hard disk or on an external storage device such as a floppy disk or CD-ROM

Course ILT Computer types Mainframes Minicomputers Personal computers Portable computers Networked computers

Course ILT Mainframes First computers, introduced in 1950s Used by large businesses Support 100 to 500 users Very expensive Used for very large processing tasks

Course ILT Minicomputers Support 10 to 100 users Smaller and less expensive than mainframes

Course ILT Personal computers (PCs) Small, self-contained computers with their own CPUs Used by home and business users

Course ILT Portable computers Useful for people on the move Smaller and more lightweight than PCs

Course ILT Networked computers Connected to other computers Two common terminal types: –Intelligent: Has its own OS –Dumb: Runs off the server’s OS

Course ILT Topic B Topic A: Overview of information technology Topic B: Hardware and storage devices Topic C: Software Topic D: Networks

Course ILT The CPU Controls computer processes Within the system unit Speed measured in gigahertz (GHz)

Course ILT Features of a CPU Control unit: –Executes instructions in sequence –Controls movement of data in the PC –Is like a traffic light at a busy intersection Arithmetic and logic unit (ALU): –Performs math and logic –Is like a small, powerful calculator Memory access: –Provides access to memory for storage of results for later use

Course ILT Input devices Enter information into a computer Examples: –Mouse –Keyboard –Trackball –Touchpad –Light pen –Joystick –Digital camera –Microphone –Bar code reader –Scanner

Course ILT Output devices Send information out from a PC Examples: –Speakers –Monitors –Printers

Course ILT Memory types Random access memory (RAM) Read-only memory (ROM)

Course ILT RAM Temporary storage for programs and other data while you work on them Most PCs have at least 128 MB

Course ILT ROM Small startup instructions placed in a permanent memory chip by the manufacturer

Course ILT Storage devices Capacity measured in megabytes (MB) Types: –Floppy disks –CD-ROMs –Hard disks –Zip disks –Tape drives

Course ILT Floppy disks Store up to 1.44 MB of data Usually 3.5" square disks Removable

Course ILT Hard disks Fixed permanently in a hard disk drive inside a system unit Used to store the operating system, applications, and data

Course ILT CD-ROMs Read-only memory devices (but CD-R and CD-RW discs are recordable) Store up to 650 MB of data Portable and can be used on any computer that has a CD-ROM drive

Course ILT Zip disks Store up to 250 MB of data Used for backing up files or transporting large files

Course ILT Tape drives Work like a tape recorder Vary in capacity and access speed Relatively expensive Generally used to back up data

Course ILT Memory units Smallest unit is a binary digit (bit): –Represented by 0 or 1 8 bits = 1 byte 1000 bytes = one kilobyte (KB) One million bytes = 1 megabyte (MB) One billion bytes = 1 gigabyte (GB) One trillion bytes = 1 terabyte (TB)

Course ILT Performance factors CPU speed Amount of RAM Hard disk speed Hard disk capacity

Course ILT CPU speed Governed by a clock Measured in millions of cycles per second, or megahertz (MHz) –700 MHz means 700 million operations per second

Course ILT RAM Measured in megabytes (MB) Most computers have at least 128 MB

Course ILT Hard disk speed and capacity Speed is judged by how fast the disk can access files Capacity is measured in gigabytes (GB)

Course ILT Topic C Topic A: Overview of information technology Topic B: Hardware and storage devices Topic C: Software Topic D: Networks

Course ILT Operating system Loads automatically when you switch on a computer Main roles: –Controls hardware and software –Permits you to manage files –Acts as intermediary between user and applications

Course ILT Application software Performs specific tasks: –Word processing –Calculations –Information storage and retrieval –Accounting Cannot function without the OS

Course ILT Software development process 1.Research 2.Analysis 3.Programming 4.Testing 5.Release

Course ILT Topic D Topic A: Overview of information technology Topic B: Hardware and storage devices Topic C: Software Topic D: Networks

Course ILT Local area network (LAN) A network connecting computers at a single site

Course ILT Wide area network (WAN) Network over many sites: –Across a country, such as a bank’s network of automatic teller machines –Across the globe, such as a multinational company’s communications network

Course ILT Public Switched Telephone Network (PSTN) Regular telephone system Analog system (transmits in continuous waves) Uses a modem to convert between digital and analog signals

Course ILT Integrated Services Digital Network (ISDN) Digital Greater capacity than analog lines Allows simultaneous transmission of voice, data, fax, and video

Course ILT The Internet A vast network of computers throughout the world (a network of networks) Requirements to connect: –ISP –Computer –Modem

Course ILT Intranets Networks of computers used within a company or an organization Benefits: –Sharing information among employees –Sharing resources and hardware

Course ILT Unit summary Learned about information technology (IT), hardware, and software, and learned how to identify types of computers Learned about computer hardware and the factors that influence computer performance Learned the difference between application and operating system software, and learned about the software development process Learned about the difference between LANs and WANs, and learned how to describe the Internet and intranets