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CHAPTER 3COMPUTER SOFTWARE

Application Software – The programs/software/apps that we run to do things like word processing, web browsing, and games.

System Software – Programs such as the operating system and utility programs that control the computer and its devices and enable application software to run.

Functions of an OS (operating system)Functions of an OS (operating system)During the boot process, the essential portion, or core, of the operating system (called the kernel) is loaded into memory.

Running Programs/ApplicationsThe most important function for an operating system is to run our applications/software/programs.• Multitasking – the ability to run multiple programs simultaneously. The CPU switches between all the programs quickly to make it appear they are all running simultaneously.• Multiprocessing – When a computer has multiple CPU’s or multi-core CPU’s and each works on a different task.• Parallel processing – When a single program is designed to be run on multiple computers or CPU’s. E.g. when you submit a Google search, thousands of computers at Google work on your request.

Device management• Communication by the OS to all hardware (e.g. display, keyboard, network, printer) is through a device driver.

Functions of an OS (continued)Functions of an OS (continued)Disk and File management• Provide a file system so our files can be stored and retrieved. Hard disks, floppy disks, DVD’s, and flash drives all have different file systems.• File systems may include encryption and compression.

Networking (Internet)• Communicate to the world through the network card or modem.• TCP/IP is the most popular networking protocol.

Security • OS’s provide secure logins, permissions to files and folders, encryption, firewalls, virus detection, etc.

User Interface• Most OS’s have a graphical user interface (GUI). Some computers have a command-line interface.• The OS provides applications with common interface elements such as windows, menu bars, text boxes, check boxes, etc.

Categories of OS’sCategories of OS’s

OS Interfaces:OS Interfaces:Command LineCommand Line

Most computers today have a graphical user interface (GUI). In the past most computers had a command-line interface. Many UNIX computers used for servers still have a command-line interface. Windows also has a command prompt.

OS Interfaces: Graphical User Interface (GUI)OS Interfaces: Graphical User Interface (GUI)

Although Xerox is credited for developing the GUI, Apple Mac’s popularizedGUI’s in the 1980’s. Apple’s latest is Mac OSX which runs on top of UNIX.

History of History of Microsoft OS’sMicrosoft OS’s

Windows 3.0 - 1990

Windows 1.0 - 1985

Microsoft’s first OS was DOS.

The UNIX OS was developed at Bell Labs (AT&T) in 1969. Also created at Bell Labs using UNIX was the C programming language and TCP/IP (Internet’s protocol).

Today, there are many flavors of UNIX:• Solaris runs on SUN computers• Mac OSX runs on Apple computers• Linux is free and will run on PC’s

Other notables: UNIX is known to be more reliable and efficient than Windows. UNIX is widely used by the telecom industry. E.g., every cell phone tower uses a UNIX computer to switch your calls and log information. Since TCP/IP was developed on UNIX, most Internet servers (web, e-mail) are UNIX. The kernel (core of OS) and user interface are separate. Therefore, you can use different shells (interfaces) to access your computer. Unlike Windows, UNIX is multiuser (supports multiple users) and can be used on mainframe computers. There’s a good chance you have a UNIX computer in your home. Where?

UNIXUNIX

Linux Mascot

OS’s for Portable DevicesOS’s for Portable Devices

Symbian OS is used on many phones such as Ericsson, Nokia, and Samsung.

Windows Phone 7

iPhone iOS

Palm OS

Android by Google

Software Categories

Commercial software: copyrighted software that is developed, usually by a commercial company, for sale to others

Shareware: copyrighted software that is distributed on the honor system; consumers should either pay for it or uninstall it after the trial period

Freeware: copyrighted software that may be used free of charge (e.g. Firefox)

Public domain software: software that is not copyrighted and may be used without restriction

Open Source: software that includes the source code so that it may be modified. This software is usually free and may or may not be copyrighted.

Firmware: another name for software that is embedded in the hardware device. It is often stored in a ROM chip. Cars have firmware.

Installed vs. Web-Based SoftwareInstalled software must be installed on a computer before it is run.

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Web-based software is run directly from the Internet.

Graphics Software

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Audio Capture and Editing Software

• For creating and editing audio files, audio capture and audio editing software is used.

• To capture soundfrom a microphone,sound recordersoftware is used; tocapture sound froma CD, rippingsoftware is used.

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Video Editing Software

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