Lesson 4 What Is Software Computer Literacy BASICS

Lesson 4: What Is Software? Computer Literacy BASICS Microsoft Office XP: Advanced Course

Objectives n n Distinguish between software and hardware. Explain how a computer software program works. Understand the steps involved in software development. Describe the difference between applications software and systems software. Microsoft Office XP: Advanced Course 2

Objectives (cont. ) n n n Describe three categories of systems programs. Describe operating systems for microcomputers, including network operating systems. Define a user interface. Microsoft Office XP: Advanced Course 3

Objectives (cont. ) n n Explain the difference between a command-line user interface and a graphical user interface. Understand the boot process a computer goes through when you start it. Microsoft Office XP: Advanced Course 4

Vocabulary n n n n Algorithm Applications software Boot Graphical user interfaces (GUIs) Language translators MS-DOS Multitasking n n n n Network operating system Operating systems Software development Systems software Unix User interface Utility software Microsoft Office XP: Advanced Course 5

Hardware vs. Software n n Computer systems consist of both hardware and software. Hardware has little value without software, and software cannot run without hardware to run it. Microsoft Office XP: Advanced Course 6

What Is Hardware? Hardware refers to anything you can physically touch: n n The keyboard and the mouse The monitor and the printer The motherboard and expansion cards All the other components in the computer case or attached to the computer Microsoft Office XP: Advanced Course 7

What Is Software? Software consists of the instructions issued to the computer to perform specific tasks: n n The software on a computer system refers to the programs that make the computer run. Software programs are lists of instructions in code that the computer understands that tell the computer what to do. Microsoft Office XP: Advanced Course 8

How Software Programs Work n n A computer processes data by applying rules called algorithms. An algorithm creates a logical progression of steps needed to accomplish a task. Microsoft Office XP: Advanced Course 9

An Algorithm to Solve a Household Problem: Dirty Laundry Microsoft Office XP: Advanced Course 10

Software Development Software development is a multistep process that begins with a need to perform a task more efficiently using a computer: n n First, the programmer breaks down the problem into a series of steps in an algorithm. The programmer may use a flowchart to show different paths the program will take. Microsoft Office XP: Advanced Course 11

Software Development (cont. ) n n Next, the programmer writes the steps in a computer programming language or code, using formal terms and syntax. Then the computer translates the code into machine language it can understand uses the translated commands to execute a program. Microsoft Office XP: Advanced Course 12

Debugging Software n n n The software development process does not end when the computer executes the program. Errors in syntax or even spelling can cause problems and distort program results. Tests of the software find and fix “bugs” or errors in the code so it will run properly. Microsoft Office XP: Advanced Course 13

Types of Software There are literally thousands of software programs you can buy, but all of them can be grouped into one of two categories: n n Applications software Systems software Microsoft Office XP: Advanced Course 14

Applications Software n n Application software consists of programs that were created to perform a specific task. Application software is also called productivity software. Microsoft Office XP: Advanced Course 15

Applications Software (cont. ) n The most common types of application software ¡ ¡ ¡ Word-processing programs Spreadsheet software Presentation software Database software Web browsers Games Microsoft Office XP: Advanced Course 16

Systems Software n n n Systems software refers to the programs that are used to manage computer system resources. Systems software coordinates and controls the resources and operations of the computer itself. The three categories of systems software ¡ Operating systems ¡ Utility programs ¡ Language translators Microsoft Office XP: Advanced Course 17

Operating Systems n n n Operating systems provide an interface between the user and the computer. There are many brands and versions of operating systems. An operating system is designed to work with a specific processor. Microsoft Office XP: Advanced Course 18

An Operating System Is an Interface Between Users and Computers Microsoft Office XP: Advanced Course 19

Utility Programs Utility programs are designed to help perform housekeeping chores for the computer: n n n Manage the computer’s resources Perform file and folder management tasks Clean up unused files from the hard disk Defragment disk storage Copy files from one disk to another Back up data to disk or tape Microsoft Office XP: Advanced Course 20

Language Translators n n n Computers cannot read program statements in programming language format, such as Visual Basic or Java program statements. Language translator programs convert program language code into machine code that can be understood by the computer. Once converted to machine code, the program can be run and executed by the computer. Microsoft Office XP: Advanced Course 21

Microcomputer Operating Systems n n If your computer is a Macintosh, you are probably using a Mac OS. If your computer is a PC or is PC compatible, you are most likely using one of these operating systems: ¡ ¡ ¡ DOS A combination of DOS and Windows A standalone version of Windows Microsoft Office XP: Advanced Course 22

Mac OS n n n Macintosh computers were introduced by Apple Computer in 1984. Macintosh had one of the first GUI operating systems, with icons that represented programs, documents, and disks. This was also the first operating system to provide an on-screen help system. Microsoft Office XP: Advanced Course 23

DOS n n n IBM introduced its first PC in 1981. Its operating system was called DOS, which stands for Disk Operating System. DOS is a command-line interface operating system. The user had to enter commands at a screen prompt. It was a single-tasking operating system, which meant that only one program at a time could be executed. Microsoft Office XP: Advanced Course 24

Windows n n Windows was Microsoft’s first GUI operating system, released in 1987. The first versions were called operating environments because they acted as a shell around the DOS operating system and worked in combination with DOS. Microsoft Office XP: Advanced Course 25

Windows n n n Applications installed on a Windows system appeared as icons that were activated by clicking them, similar to the Mac OS Finder interface. The earliest versions of Windows were labeled Windows 3. 0, 3. 1, and so on. The first true multitasking version of Windows was Windows 95, which also included support for networking computers. Microsoft Office XP: Advanced Course 26

Windows n n n Windows 98 improved on Windows 95 and offered Internet integration and support for the USB bus. Windows 2000 was an update to Windows 98 and Windows NT and included tools for Web site creation. The latest version is Windows XP, which provides increased stability and device recognition. Microsoft Office XP: Advanced Course 27

The Windows XP Operating System Microsoft Office XP: Advanced Course 28

Other Operating Systems n n n Unix was developed by AT&T and is another early operating system that is still used today. It is a portable operating system, which means it can run on any hardware platform. Variants of Unix include the freeware operating system Linux and IBM’s AIX. Microsoft Office XP: Advanced Course 29

Network Operating Systems n n A network operating system (NOS) is designed to allow multiple computers to be connected and talk to each other. The most popular networking operating systems include ¡ ¡ ¡ Microsoft Windows NT Novell’s Netware IBM’s Warp Server Microsoft Office XP: Advanced Course 30

User Interfaces n n n You are probably familiar with the user interface of an operating system because it is what you see when you use the computer. The user interface determines how “user friendly” the operating system is. There are two commonly used types of operating system interfaces, command-line interfaces and graphical user interfaces. Microsoft Office XP: Advanced Course 31

Command-Line Interfaces n n n With this interface, you must type exact commands into the computer from a command prompt. You must memorize many commands and keywords. Command-line interfaces are not as user friendly as graphical user interfaces. Microsoft Office XP: Advanced Course 32

Graphical User Interfaces n n Menu-based interfaces were easier to use, providing options so that commands did not need to be memorized. The breakthrough in ease of use came with the introduction of graphical user interfaces (GUIs). Microsoft Office XP: Advanced Course 33

Graphical User Interfaces (cont. ) n n Users manipulate on-screen icons to perform functions, usually with a mouse or other pointing device. Most of today’s personal computers are equipped with some type of userfriendly GUI. Microsoft Office XP: Advanced Course 34

Comparing User Interfaces Command-Line Interface Command prompt Icons representing programs or files Microsoft Office XP: Advanced Course Graphical User Interface 35

Starting Your Computer n n When you start your computer, operating system commands are loaded into memory. Each operating system starts the computer in its own individual way. When you turn on a computer, you boot the system. POST (Power-on Self Test), a series of tests that check RAM and verify that the keyboard and disk drives are connected to the computer, runs when you start your computer. Microsoft Office XP: Advanced Course 36

Starting Your Computer (cont. ) n Then the BIOS (Basic Input Output System) searches for the boot record. The hard disk drive C is typically the startup drive, so that is where the BIOS will look first for the boot record. BIOS is built-in software on a ROM chip. It contains all of the code that controls the monitor, keyboard, disk drives, and other components. Microsoft Office XP: Advanced Course 37

Starting Your Computer (cont. ) n n The boot record, which includes several files, is loaded into RAM. These files contain programming configuration instructions for hardware devices and software applications that you may have installed on your computer. Next, the software drivers are loaded. Drivers enable you to use your printer, modem, scanner, or other devices. Generally, when you add a new device to your system, drivers are installed for that device. Microsoft Office XP: Advanced Course 38

Starting Your Computer (cont. ) n n Next to be loaded is the GUI or graphical user interface, such as Windows XP. When loading the GUI, the operating system reads the commands for your desktop configuration. It also loads whatever programs you have previously specified into the Windows Startup Folder. If everything goes as it should, the GUI displays the desktop and the computer is ready to use. Microsoft Office XP: Advanced Course 39

Summary n n Hardware refers to anything you can touch. Software is instructions that tell the computer what to do. Software is also called a program. A computer processes data by applying rules called algorithms. Microsoft Office XP: Advanced Course 40

Summary (cont. ) n n An algorithm creates a logical progression of steps needed to accomplish a task. Software development is a multistep process that includes writing the command code in a programming language, having the computer translate the code into machine language, and then debugging and testing the program. Microsoft Office XP: Advanced Course 41

Summary (cont. ) n n n The two basic types of computer software applications software, also called productivity software, and systems software. Systems software coordinates and controls the resources and operations of a computer system. Three major categories of systems software operating systems, utilities, and language translators. Microsoft Office XP: Advanced Course 42

Summary (cont. ) n n n Operating systems provide an interface between the user and application program and the computer hardware. Utility programs help users complete specialized tasks, such as file management. Language translators convert code written in English-based software programs into machine language. Microsoft Office XP: Advanced Course 43

Summary (cont. ) n n n All computers have operating systems. Mac OS is used with Apple’s Power Macintosh computers and Power Macintosh clones. DOS was introduced with the IBM PC in 1981 and is a character-based operating system. Microsoft Office XP: Advanced Course 44

Summary (cont. ) n n n Microsoft introduced the first version of Windows in 1987; this was an operating environment. Windows 95 was Microsoft’s first true multitasking operating system. Unix is a portable operating system. Microsoft Office XP: Advanced Course 45

Summary (cont. ) n n n Network operating systems allow a group of two or more microcomputers to be connected. The user interface is the part of the operating system with which we are most familiar. The two most common user interfaces are command-line interfaces and graphical user interfaces. Microsoft Office XP: Advanced Course 46

Summary (cont. ) n n n Most of today’s computers come with some type of graphical user interface. Icons are symbols that represent documents, software programs, disks, and so forth. A graphical interface includes standard text and graphics so that data processed in one application program can be shared by other applications. Microsoft Office XP: Advanced Course 47