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Software:
System
Software
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
Sumber:
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Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
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Outline Materi
• System Software: The Power behind the
Power
• The Operating System: What It Does
• Other System Software: Device Drivers &
Utilities
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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
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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
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The Operating System: What It Does
• Booting
– The process of loading an OS into the computer’s
main memory
– The steps are:
1. Turn the computer on
2. Diagnostic routines test main memory, CPU, and other
hardware
3. 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
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• 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
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• 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
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• 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
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• 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
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• 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
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Other System Software: Device
Drivers & Utilities
• Device Drivers
– 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
• 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
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• 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!
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Common Features of the User
Interface
• 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
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• 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
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• 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
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• Mouse
– Handy tool for dragging and dropping text,
graphics – Useful for
navigating menus on unfamiliar applications
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•
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
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•
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
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• 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
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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
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• 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
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• 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
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• 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
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• 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
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