Download ppt - Lesson 4: What Is Software? Computer Literacy BASICS

Lesson 4: What Is Software?

Computer Literacy BASICS

Microsoft Office XP: Advanced Course

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Objectives

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.


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Objectives (cont.)

Describe the three categories of systems programs.

Describe operating systems for microcomputers, including network operating systems.

Define a user interface.


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Objectives (cont.)

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.


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Vocabulary

Algorithm Applications software Boot Graphical user

interfaces (GUIs) Language translators MS-DOS Multitasking

Network operating system

Operating systems Software

development Systems software Unix User interface Utility software


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Hardware vs. Software

Computer systems consist of both hardware and software.

Hardware has little value without software, and software cannot run without hardware to run it.


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What Is Hardware?

Hardware refers to anything you can physically touch:

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


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What Is Software?

Software consists of the instructions issued to the computer to perform specific tasks:

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.


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How Software Programs Work

A computer processes data by applying rules called algorithms.

An algorithm creates a logical progression of steps needed to accomplish a task.


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An Algorithm to Solve a Household Problem: Dirty Laundry


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Software Development

Software development is a multistep process that begins with a need to perform a task more efficiently using a computer:

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.


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Software Development (cont.)

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 and uses the translated commands to execute a program.


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Debugging Software

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.


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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:

Applications software Systems software


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Applications Software

Application software consists of programs that were created to perform a specific task.

Application software is also called productivity software.


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Applications Software (cont.)

The most common types of application software are Word-processing programs Spreadsheet software Presentation software Database software Web browsers Games


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Systems Software

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 are Operating systems Utility programs Language translators


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Operating Systems

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.


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An Operating System Is an InterfaceBetween Users and Computers


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Utility Programs

Utility programs are designed to help perform housekeeping chores for the computer:

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


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Language Translators

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.


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Microcomputer Operating Systems

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


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Mac OS

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.


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DOS

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.


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Windows

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.


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Windows

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.


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Windows

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.


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The Windows XP Operating System


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Other Operating Systems

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.


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Network Operating Systems

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


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User Interfaces

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.


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Command-Line Interfaces

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.


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Graphical User Interfaces

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).


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Graphical User Interfaces (cont.)

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 user-friendly GUI.


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Comparing User Interfaces

Command-Line Interface GraphicalUser Interface

Command prompt

Icons representing programs or files


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Starting Your Computer

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.


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Starting Your Computer (cont.)

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.


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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.


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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.


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Summary

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.


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Summary (cont.)

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.


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Summary (cont.)

The two basic types of computer software are 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 are operating systems, utilities, and language translators.


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Summary (cont.)

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.


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Summary (cont.)

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.


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Summary (cont.)

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.


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Summary (cont.)

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.


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Summary (cont.)

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.