system software
DESCRIPTION
System Software. Chapter 4 of Computers: Understanding Technology (Third edition). System Software in Context. Hardware Input (Ch. 2) Processing (Ch. 2) Output (Ch. 3) Storage (Ch. 3) Software System software(Ch. 4) Application software (Ch. 5). System Software. Operating Systems - PowerPoint PPT PresentationTRANSCRIPT
System Software
Chapter 4 of Computers: Understanding Technology (Third
edition)
1September 16, 2009 - William Pegram
System Software in Context
• Hardware– Input (Ch. 2)– Processing (Ch. 2)– Output (Ch. 3)– Storage (Ch. 3)
• Software– System software(Ch. 4)– Application software (Ch. 5)
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System Software
• Operating Systems
• Utility Programs
• Language Translators – Compiler, Interpreter
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Operating Systems
• When computer is started, part of operating system is loaded into random access memory (RAM) from the boot drive (typically the hard drive)
• Functions of operating system– Managing main memory– Controlling peripheral devices– Managing file operations– Monitoring system performance– Providing user interface
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Operating System Functions
• Output buffers – selected areas of RAM which hold data waiting to be transferred to an output device – This frees the CPU to move on to something else; output device will often be slower – print spooling is example
• Multitasking – User can work on more than 1 application at the same time
• Drivers – programs that allow the operating system to communicate with a peripheral device – the driver is often specific to a specific device, manufacturer and model number; typically this means that the application program need only know how to communicate with Windows and not with each peripheral device
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Operating System Functions (cont.)
• Security features– Operating system can force user to enter a
correct username and password to access the computer
– Windows XP and Windows Vista can provide multiple user accounts on a single machine and different levels of privileges among the accounts
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User Interfaces
• Command line – e.g. DOS
• Graphical User Interface (GUI) – e.g. Windows
• Graphical user interface was used in the Alto computer developed by Xerox Palo Alto Research Center, and later used in the Apple Lisa and Macintosh computers
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Elements of GUI
• On-Screen desktop with graphical elements displayed – icons, buttons, etc.
• Display windows – title bar, scroll bar, and other common features
• Menus with drop down menus• Toolbars with icons• Dialog boxes to provide information and prompt
responses – tabs, radio buttons, checkboxes, text boxes, OK/cancel buttons
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Personal Computer Operating Systems
• Windows XP (ITN 114)
• Windows Vista
• Macintosh
• IBM OS/2
• Linux (ITN 170, ITN 270)
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Server Operating Systems
• Some operating systems are used with networks, allowing multiple users to connect to the server
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Server Operating Systems
• Novell NetWare• Windows NT Server• Windows 2000 Server (ITN 111)• Windows 2003 Server (ITN 115)• Windows 2008 Server • Unix (ITN 171 and ITN 271)• Linux (ITN 170 and ITN 270)
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Wireless Device Operating Systems
• Palm OS
• Windows Mobile
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Utility Programs
• Antivirus – Norton, Symantec, McAfee• Firewalls – security system that acts as
boundary to protect computer or network• Diagnostic• Uninstaller – remove all files associated with a
program• Disk scanner – identify bad sectors• Disk defragmenters • File compression – WinZip, PKZIP, and Stuffit
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Utility programs (cont.)
• Backup
• Disk toolkits – fix problems with a disk
• Spam blocker
• Anti-spyware – Windows Defender
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Language Translators
• Programmers generally write programs in high-level languages – Java, COBOL, Fortran
• Compilers translates entire program into machine language file; that file is then executed whenever program is run
• Interpreter translates one statement at a time without producing a file, so repeated runs require interpreter each time
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