Software: System Software Sumber: Chapter 3. Software: Tools for Productivity and Creativity, p.117 Williams, B.K, Stacy C. Sawyer (2007). Using Information Technology: A Practical Introduction to Computers & Communications. Seventh Edition, McGraw-Hill, New York. ISBN-13: 978-0-07-110768-6

Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : menjelaskan: pengertian dan komponen system software, dan fungsi-fungsi sistem operasi

Outline Materi System Software: The Power behind the Power The Operating System: What It Does Other System Software: Device Drivers & Utilities Common Features of the User Interface Common Operating Systems

System Software: The Power behind the Power Application Software Software developed to solve a particular problem for users Either performs useful work on a specific task Or provides entertainment We interact mainly with this software System Software Enables application software to interact with the computer Helps the computer to manage its own internal and external resources

System Software: The Power behind the Power System Software has 3 basic components Operating System (OS) The principal component of system software Low-level, master system of programs to manage basic computer operations Some hardware requires specific Operating Systems Macintosh computers run Macintosh OS PCs run Microsoft Windows, Linux, or BSD Device Drivers Help the computer control peripheral devices Utility Programs Used to support, enhance, or expand existing programs in the computer

The Operating System: What It Does Booting The process of loading an OS into the computer’s main memory The steps are: Turn the computer on Diagnostic routines test main memory, CPU, and other hardware Basic Input/Output System (BIOS) programs are copied to main memory BIOS contains instructions for operating the hardware The computer needs those instructions to operate the hardware and find a copy of the OS Boot program obtains the OS and loads it into computer’s main memory

The Operating System: What It Does

The Operating System: What It Does Central Processing Unit (CPU) Management Kernel is the supervising software that manages CPU Kernel must remain in memory while the computer runs If another program uses the kernel’s memory when the kernel needs it, the computer will crash Memory Management OS keeps track of memory locations to prevent programs and data from overlapping each other Swaps portions of programs and data into the same memory but at different times Keeps track of virtual memory Queues, Buffers, Spooling

The Operating System: What It Does Central Processing Unit (CPU) Management (continued) Queues, Buffers, Spooling Queue: First-in, First-out (FIFO) sequence of data or programs that waits in line for its turn to be processed Buffer: The place where the data or programs sit while they are waiting To Spool: The act of placing a print job into a buffer Needed because the CPU is faster than printers The CPU can work on other tasks while the print jobs wait

The Operating System: What It Does File Management A file is either a Data File: a named collection of data Program File: a program that exists in a computer’s secondary storage The File System arranges files in a hierarchical manner Top level is Directories (aka Folders) Subdirectories come below Folders Find files using their pathname C:/MyDocuments/Termpaper/section1.doc

The Operating System: What It Does Task Management Required for computers that accommodate multiple users Required for computers that allow multiple simultaneous applications Methods of processing two or more programs Multitasking By one user on one processor Time-sharing By multiple users in round-robin fashion on one processor Multiprogramming By multiple users concurrently on one processor Multiprocessing By one or more users simultaneously on two or more processors

The Operating System: What It Does

The Operating System: What It Does Security Management Operating Systems permit users to control access to their computers Users gain access using an ID and password You set the password the first time you boot up a new computer System Administrators can set up new accounts and assign new passwords

Other System Software: Device Drivers & Utilities Specialized software programs that allow input and output devices to communicate with the rest of the OS When you get a brand-new printer or monitor, you may also need to install the device driver for it Device drivers come with new hardware, or download from the manufacturer’s website, or sites like www.driverguide.com or www.windrivers.com 3-14

Other System Software: Device Drivers & Utilities Service programs that perform tasks related to the control and allocation of computer resources Some come with the OS, others can be bought separately like Norton SystemWorks, McAfee Utilities

Other System Software: Device Drivers & Utilities Practical Utility programs perform the following tasks Virus protection Data compression File defragmentation Disk scanner & disk cleanup Backup Data recovery Discussion Question: How many of you have lost important files such as a term paper? Didn’t you wish you had made a backup copy? ALL data media are subject to possible failure and data loss! 3-16

Common Features of the User Interface The user-controllable display screen you use to interact with the computer Keyboard and Mouse User input devices that you use to interact with the display screen Both devices have special-purpose keys Keyboard Special-purpose keys: Esc, Ctrl, Alt, Del, Ins, Home, End, PgUp, PgDn, Num Lock Mouse special-purpose keys: left-click, right-click, and (on some mice) scroll wheel or center click 3-17

Common Features of the User Interface Keyboard Function Keys – let you quickly perform specific tasks Escape Key – lets you quit a task Ctrl and Alt – use combination with another key to bypass using the mouse – Ctrl + S will save a document, Alt + Tab will let you switch between running applications 3-18

Common Features of the User Interface Keyboard continued Application key – quickly displays the shortcut menu for any item on your screen Status lights – indicate if your Num Lock or Caps Lock keys are on Numeric Keypad – allows you to type in numbers when the Num Lock light is on 3-19

Common Features of the User Interface Mouse Handy tool for dragging and dropping text, graphics Useful for navigating menus on unfamiliar applications 3-20

Common Features of the User Interface Graphical User Interface (GUI) Allows you to use a mouse or keystrokes to select icons and commands from menus Replaces command-driven interfaces used in earlier programs Three main features are: desktop, icons, and menus Desktop: The system’s main interface screen Icon: Small pictorial figure that represents a program, data file, or procedure Rollover: A small text box that explains the icon when you roll your mouse over it Menus: A list of built-in commands and/or options from which to choose 3-21

Common Features of the User Interface To start an application, pick one of 3 methods: Click on the Start button on the lower left corner of the Windows desktop Click on the My Computer icon on the desktop, find the application executable on your hard disk, and click it Click on the My Documents icon on the desktop, find the document you want to open, and click it. It should automatically open the application that created it, if you have that application installed 3-22

Common Features of the User Interface Most Operating Systems have the following: Title Bar: runs across the top of the display window Menu Bar: shows the names of the pull-down menus available Toolbar: Displays menus and icons representing the most-frequently used commands Taskbar: The bar across the bottom of the Windows screen that contains the Start button A window: A rectangular frame on the computer screen through which you can view a file of data or an application 3-23

Common Operating Systems Platform The particular processor model and operating system on which a computer system is based Operating Systems are platform-specific PC (Wintel) platforms Dell, Compaq, Hewlett-Packard, IBM PCs Originally ran Disk Operating System (DOS) Currently run Linux, Unix, Windows Apple (Macintosh) platforms Run Mac OS (System 9 was proprietary, OS X is Unix-based) 3-24

Common Operating Systems Mac OS The OS that runs on Apple Macintosh computers Pioneered the easy-to-use GUI Proprietary OS System 9 is OS from 1999, but still popular Mac OS X is based on BSD Unix kernel Tiger is 2005 release of Mac OS X; features include Spotlight – a desktop search engine for locating files on local hard disk Dashboard – for creating desktop “widgets” Automator – automatically helps users to script repetitive tasks 3-25

Common Operating Systems Unix, Solaris, BSD Developed at AT&T Bell Laboratories in 1969 as minicomputer operating system Is a multitasking operating system with multiple users that has built-in networking capability and a version for every platform Unix interface GUI – An optional shell program that starts after the kernel Command interface – starts when kernel loads 3-26

Common Operating Systems Linux A flavor (version) of Unix A free, nonproprietary version of UNIX May legally be downloaded and used for free May legally be modified for free, as long as modifications aren’t copyrighted In 2000, adopted by China as national standard OS Linux vendors produce Linux Distributions Software is distributed for free Support services are sold for a profit Many PCs are set up to dual-boot Linux and Windows 3-27

Common Operating Systems Operating Systems for Handhelds Palm OS Dominant handheld OS Proprietary OS requires proprietary software Windows CE Has familiar Windows look and feel Can be directly programmed using Visual Basic 2005 Symbian OS Symbian is world’s largest producer of smartphone software Software is open-source 3-28

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