Operating System Introduction PDF

Discovering Computers OPERATING SYSTEMS & UTILITIES Linux  System Software (OS & Utilities) What is system software? Programs that Two types are control operation operating systems of computer and utility programs...

Discovering Computers OPERATING SYSTEMS & UTILITIES Linux  System Software (OS & Utilities) What is system software? Programs that Two types are control operation operating systems of computer and utility programs Operating system (OS) coordinates all activities among computer hardware resources Next  Utility Program Utility Program type of system software that allows a user perform maintenance-type tasks Usually related to managing a computer, its devices or programs Most OS include built-in utility programs 3 Discovering Computers 2011: Living in a Digital World  Operating Systems functions What are the functions of an operating system? start the computer provide a user interface manage programs manage memory control a network provide file monitor establish an Automatically management and performance Internet connection update itself other utilities Next  Operating Systems functions ✓Start and Shut down computer ✓Provide User Interface ✓Manage Programs ✓Manage Memory ✓Automatically Update Itself ✓Establish an Internet Connection ✓Monitor Performance ✓File Management ✓Control Network Next  Operating Systems Where is the operating system located? Resides on computer’s hard Different sizes of disk in most cases computers typically May reside on a ROM chip on use different handheld computers operating systems Some types of computers may have different operating systems Various operating systems often are not compatible Next (Apple MACs vs PCs)  Operating Systems functions ✓Start and Shut down computer ✓Provide User Interface ✓Manage Programs ✓Manage Memory ✓Automatically Update Itself ✓Establish an Internet Connection ✓Monitor Performance ✓File Management ✓Control Network Next Operating Systems (Cold & Warm boots) What is booting? Process of starting or restarting a computer ▪ Cold boot Turning computer on after it has been powered off ▪ Warm boot Restarting computer that is powered on ▪ Press Reset Warm boot from Windows desktop Button Warm boot from system unit Next Operating System Functions (Booting) How does a personal computer boot up? Step 1. Power supply Step 4. Results of POST are sends signal to com- compared with data in CMOS chip ponents in system unit Step 5. BIOS looks for system files Step 2. Processor on the hard disk accesses BIOS to start computer Step 6. Kernel (core) of operating Step 3. BIOS runs tests, system loads into RAM called the POST, to Step 7. Operating system in memory check components such takes control of computer as mouse, keyboard, RAM chips and adapter Step 8. Operating system displays cards desktop on screen Step 9. Operating system executes programs in StartUp folder Next  Operating System Functions Next  Operating System Functions BIOS (Basic Input Output System) Firmware (permanent software) that contains computer’s startup Instruction POST (Power-on Self Test) Check the different system components Step 7 Start Up folder Contains a list of programs that open automatically Next when you boot the computer  Operating System Functions What is the kernel? Memory resident The core of an operating system Remains in memory Manages memory and devices while the computer is Maintains the computers clocks running Starts applications The kernel is memory resident ! Each time you boot a computer, the kernel and other frequently used operating system instructions are loaded Nonresident Loading a file means the file is copied from the hard disk to the computer's Instructions remain on memory the hard disk until they are needed Resident ‫مقيم‬ Other parts of the operating system are Next nonresident  Boot Disk What is a Boot Disk? The drive from which your personal computer boots (start) Most case, drive C (the hard disk) is the boot drive Next Shut down options Sleep mode and hibernate save current state of all open documents Power off Designed to save computer Hibernating time when you Function of resume working Save any open Power button computer document and on a computer programs to hard varies disk before Sleep mode removing power from computer Save any open document to RAM, turn off all unneeded files, computer in low power state Unsaved work lost if Next power off  Shut down options Hibernation isa power-saving state designed primarily for laptops. While sleep puts your work and settings in memory and draws a small amount of power. hibernation puts your open documents and programs on your hard disk, and then turns off your computer. Sleep used when you don’t want to waste all that time shutting down your computer then turning it back on later.  Operating Systems functions ✓Start and Shut down computer ✓Provide User Interface ✓Manage Programs ✓Manage Memory ✓Automatically Update Itself ✓Establish an Internet Connection ✓Monitor Performance ✓File Management ✓Control Network Next  Operating System Functions ( GU I ) What is a user interface? Controls how you enter data and instructions and how information displays on screen. You interact with software through its user interface Types: Command-Line, (graphical) GUI command-line interface (DOS) Next  Operating System Functions (GUI) What is a graphical user interface (GUI)? User interacts with menus and visual images such as icons and buttons to issue commands Next  Operating System Functions What is Command line interface? A user type commands or presses special keys on keyboard to enter data and instruction ▪ Command line interface requires enter exact spelling, grammar and punctuation p. 8.09 Fig. 8-8 Next  Operating Systems functions ✓Start and Shut down computer ✓Provide User Interface ✓Manage Programs ✓Manage Memory ✓Automatically Update Itself ✓Establish an Internet Connection ✓Monitor Performance ✓File Management ✓Administer Security Next  Operating System Functions Single user/Single tasking OS Allow only one user to run one program at a time ▪ Early systems were single user/single tasking ▪ Smart phones often use a single user/single tasking OS today is multitasking p. 8.09 Fig. 8-8 Next  Operating System Functions multiple programs single user/ multitasking OS running Working on two or more programs that reside in memory at same time ▪ Foreground contains application you are using (display on the screen) ▪ Background contains programs that are running but are not in use (hidden partially or completely behind the foreground program) Next  Operating Systems functions ✓Start and Shut down computer ✓Provide User Interface ✓Manage Programs ✓Manage Memory ✓Automatically Update Itself ✓Establish an Internet Connection ✓Monitor Performance ✓File Management ✓Control Network Next  Manage Memory: VM What is memory management? Optimizing use ‫ يحسن استخدام‬of random access memory (RAM) Step 2. The operating system transfers data and Step 1. The program instructions operating system from disk to transfers the least memory when they recently used data are needed. and program instructions to disk The technique of because memory is swapping items needed for other between memory functions. and HD is called paging Next  Manage Memory : Job Scheduling How does an operating system schedule jobs? The OS may adjusts schedule OS tasks (jobs)include: based on a job’s priority, not always process tasks on first- come, first-served basis Sending Receiving data information from input device to output device A job is an operation the processor manages Transferring items Processing between storage instructions and memory Next  Operating Systems functions ✓Start and Shut down computer ✓Provide User Interface ✓Manage Programs ✓Manage Memory ✓Monitor Performance ✓Establish an Internet Connection ✓Automatically Update Itself ✓File Management ✓Control Network Next Operating System Functions: Performance How does an operating system monitor performance? Provides program, called performance monitor, that assesses and reports information about system resources and devices (processor, memory) Next  Operating System Functions A performance monitor is a program that assesses and reports information about various computer resources and devices 28  Operating System Functions File management includes file allocation( where stored), file attributes and any process related to files 29  Operating System Functions Operating systems typically provide a means to establish Internet connections 30  Operating System Functions Automatic update automatically provides updates to the program (include fixes program errors, enhancement security)automatically alerts user when new update Discovering Computers 2011: Living in a Digital World 31 Chapter 8  Operating System Functions Automatic update feature in OS automatically alerts users when an update is available. Page 409 Discovering Computers 2011: Living in a Digital World 32 Figure 8-12 Chapter 8  Operating Systems functions ✓Start and Shut down computer ✓Provide User Interface ✓Manage Programs ✓Manage Memory ✓Automatically Update Itself ✓Establish an Internet Connection ✓Monitor Performance ✓File Management Next ✓Control Network  Operating System Functions What is a network(server) operating system? Allows users to share printer, Internet access, files, and programs on a network Administers security by establishing user name and password for each user Next  Operating System Functions: Controlling network Some operating systems A network administrator are designed to work uses the server operating with a server on a system to: network – Add and remove users, A server operating computers, and other devices system organizes and – Install software and rule coordinates how network security multiple users access and share resources on a network 35 Types of Operating Systems What are the three categories of operating systems? Embedded Network (server) Stand Alone Next  Types of Operating Systems Page 412 Discovering Computers 2011: Living in a Digital World 37 Figure 8-14 Chapter 8  Stand-Alone Operating Systems A stand-alone operating system is a complete operating system that works on a desktop computer or notebook computer. It does not need to be connected to any other computer to run Windows Mac OS X 7 UNIX Linux 38  Window 7 features Windows 7 is Microsoft’s fastest, most efficient operating system to date Offer quicker program start- up, enhance searching and diagnosis capabilities Easy to use interface Include networking capabilities 39  Stand-Alone Operating Systems: Mac OS X The Macintosh operating system has set the standard for operating system ease of use The first OS to bring the GUI to the world Latest version is Mac OS X snow leopard 40  Mac OS X Features New desktop search technology Desktop area for mini-programs called widget Built in, fast web browser Improved backup utility Smaller memory footprint Faster shut down and booting 41 Stand-Alone Operating Systems: UNIX UNIX is a multitasking operating system developed in the early 1970s. More secure and stable Linux is an open-source, popular, multitasking UNIX-type operating system 42  Operating Systems: UNIX What is UNIX? Used by power users because of its flexibility and power Most versions offer a GUI UNIX is both a stand-alone and a network operating system Some versions have a command-line interface, but most offer a GUI Next  Operating Systems: Linux What is Linux? Popular, free, multitasking UNIX-type operating system Open-source software — e code is available to public It is both a stand-alone and a network OS High security  Server Operating Systems Windows UNIX Server 2008 Linux 45  Server Operating Systems An operating system that designed specifically to support network (with file and task manager) Resides on server An OS that organize how multiple users access and share resource on the network Windows Server 2008 is an upgrade to Windows Server 2003 – Enabling users to share data – Enhanced server security – Protection against malicious software attacks – Share many technologies with windows 46  UNIX Server Operating Systems UNIX is both stand-alone OS and server OS Work with multiple processors using multiprocessing UNIX is called a e Multipurpose OS because it is stand- alone and server operating system (fall into both categories) Many web server use UNIX as their operating system 47  Differences between Linux & Windows Application Software: ✓There is more application software available for Windows ✓However, if you buy a copy of Windows on a CD-ROM, you get no application software with it ✓if you buy a copy of Linux on a CD-ROM, it typically comes with free applications software ✓On contrary, installing software under Linux varies with each version and is not easy or obvious as Windows  Differences between Linux & Windows Viruses and spyware (malicious software): ✓The vast majority of all malicious software runs on Windows ✓Spyware is the worst problem effecting Windows based computer ✓Linux has a good reputation of being more secure and stable.. Differences between Linux & Windows Hardware devices supported by the OS: ✓More hardware works with windows that works with Linux. ✓This is because hardware vendors write drivers for Windows more often than do for Linux Hardware the OS runs on: ✓Linux runs on many different hardware platform, not so with Windows. ✓Because of its ability to run without a GUI, Linux can run on very old computers to the highest category of computers Differences between Linux & Windows Multiple Users: ✓Linux is a multi-user system, Windows is not. ✓Windows (one installed on PC) is designed to be used by one person at a time Case Sensitivity: ✓When entering command in a DOS/command window under any version of Windows ,”dir” is the same as “DIR” ✓In Linux, “dir” is a different command than “DIR” ✓Linux is case sensitive Windows not  Embedded Operating Systems An embedded operating system resides on a ROM chip on a mobile device or consumer electronic device Scaled down OS Mainly support GUI and internet access and multimedia Windows Palm OS iPhone OS Mobile Google Embedded BlackBerry Pages 418 - 420 Android Linux Discovering Computers 2011: Living in a Digital World 52 Chapter 8  Embedded Operating Systems Iphone OS: developed Android: designed by by apple for iPhone and Google for mobile iPad touch device Multi-touch devices Open Source Wi-Fi access capability Wi-Fi access Web browser Easy web browsing Used only on apple More PC like interface devices Used by different phone manufacturer 53  Differences between Iphone OS& Android Interface: ✓Iphone more color uniformity. Applications: ✓A lot more of application available for android, not because any technical difference between the operating systems, but simply because Android is open source. ✓If you want an application to carry out a specific task, you have a significantly higher chance of finding it for android than for Iphone OS  Differences between Iphone OS& Android Games: ✓ Android lags well behind Iphone in games. Security: ✓ Iphone OS owns a strong reputation of being secure ✓ Apple exercises strict quality control on the applications it accept into its market place, this brings higher levels of security and quality control ✓ The only application that can be downloaded to Iphone OS device are those that come from the Apple Application store ✓ Google play policies are not as strict as Apple, so less secure..  Utility Program Utility Program type of system software that allows a user perform maintenance-type tasks Usually related to managing a computer, its devices or programs Most OS include built-in utility programs 56  Operating System Functions Operating systems often provide users with the capability of: Searching for Viewing Securing a Managing files files images computer Uninstalling Cleaning up Defragmenting Diagnosing programs disks disks problems Backing up Setting up files and disks screen savers 57 58  Utility Programs: File Manager A file manager is a utility that performs function related to file management (dealing) File manager performs: – Displaying a list of files on a storage media – Organizing files in folders – Copying , renaming, deleting, moving and sorting files 59  Utility Programs: Search utility Search utility is a program that attempts to locate a file on your computer based on criteria you specific Criteria: – Word contained in a file – File name – File location Discovering Computers 2011: Living in a Digital World 60 Chapter 8  Utility Programs: Uninstaller Uninstaller utility is a utility that removes a program, as well as any associated entries in the system files When installing a program, OS record information it uses to run program in system files 61  Operating System Utility Programs What is an uninstaller program? Removes a In Windows XP, program and uninstaller is in Add/Remove all associated files Programs in Control Panel p. 8.17 Next OS Utility Programs (Win XP) Backup What is a backup utility? Copies selected files or entire hard disk onto another storage medium (another hard disk, USB flash) Most files compressed during backup to require less storage space ▪Full backups—include all files and data ▪Incremental backups— include only those files changed or added since the previous backup Next OS Utility Programs Backup 64 Operating System Utility Programs What is a screen saver? (not needed for LCDs) Causes monitor’s screen to display moving image or blank screen if there is no activity for a specified time. Prevents burn-in on back of phosphor screen p. 8.18 Fig. 8-22 Next  Utility Programs (Antivirus Utilities) What is a virus? Potentially damaging computer program Virus spread throughout and damage your files and OS. Affects computer without user’s knowledge SIGNS OF VIRUS INFECTION p. 8.28 Fig. 8-36 Next  Utility Programs (Antivirus) What is an antivirus program? (Symantec, McAfee, AVG,Norton) Identifies and removes viruses in memory, storage media, and incoming files Must be updated frequently p. 8.28 Fig. 8-37 Next  Utility Programs: File Compression What is a file compression utility? Shrinks size of files to free up room and improve performance Compressed files are sometimes called zipped files popular utility:WinZip® Another one: Gzip (.tgz file extension) Decrease the size of files, resulting in faster downloads p. 8.29 Fig. 8-39 Next  Utility Programs What is spyware? Program placed on a computer without the user’s knowledge that secretly collects information about the user Often enters a computer as a result of a user installing a new program A spyware remover is a program that detects and deletes spyware. p. 426  Utility Programs What are functions provided by utility programs? ✓Managing Files ✓Searching Files ✓Uninstall Programs ✓Cleaning Up disks ✓Screen Saver ✓Protecting against Virus ✓Compressing Files ✓Removing Spyware Next p.8.17 Fig. 8-18