Transcript Chapter 4
Using Information Technology Chapter 4 System Software System Software The Power behind the Power 4.1 The Components of System Software 4.2 The Operating System: What It Does 4.3 Other System Software: Device Drivers & Utility Programs 4.4 Common Operating Systems 4.5 The OS of the Future: “The Network is the Computer” 4.6 Online Software & Application Software Providers: Turning Point for the Software Industry? System Software System software enables the application software to interact with the computer and helps the computer manage its internal and external resources. 4.1 The Components of System Software Operating system the principal component of system software Device drivers - help the computer control peripheral devices Utility programs support, enhance, or expand existing programs 4.2 The Operating System: What It Does Operating System – Also called Software platform – consists of the master system of programs that manage the basic operations of the computer. Different sizes of computers, main, mini etc and different platforms have different operating system. E.g. MS Windows XP MS Windows 2000 Professional MS Windows 2003 Advanced Server Linux ( various vendors … Red Hat popular) Free BSD Symbian OS Basic Tasks of Operating System Booting User Interface CPU Management File Management Task Management Formatting Security Management Booting The process of loading an operating system into a computer’s main memory. In addition diagnostic routines are also run at the time of booting. Cold boot Switch ON the PC Warm boot ALT+CTRL+DEL or reset the PC User interface User-controllable display screen that allows you to communicate, or interact, with your computer CPU Management Supervision and Management of Activities Memory Management The supervisor, or kernel, manages the CPU. It remains in main memory while the computer is running and directs other "nonresident" programs (programs that are not in main memory) to perform tasks that support application programs. Memory management Partitioning – In partitioning, the OS divides memory into separate areas called partitions, each of which can hold a program or data. Foreground/background – Some computer systems divide memory into foreground and background areas. Foreground programs have higher priority, and background programs have lower priority. Queues – Programs that are to be executed wait on disk in queues. A queue is a temporary holding place for programs or data. File Management Files of data and programs are located in many places on your hard disk and other secondary-storage devices. The operating system records the storage location of all files to helps you locate and gain access to it. Following are the key function of file management: Move Rename Delete Copy Back up Task Management A computer is required to perform many different tasks at once. A "task" is an operation such as storing, printing, or calculating. Among the ways operating systems (not all) manage tasks in order to run more efficiently are: Multitasking Multiprogramming Time-sharing Multiprocessing Multitasking The execution of two or more programs by one user concurrently on the same computer with one central processor. Because the processor is usually very fast, it may appear that all the programs are being executed at the same time. However, the processor is still executing only one instruction at a time. Only one program is running at any given instant of time Multiprogramming The execution of two or more programs concurrently on a multi-user operating system. Time-sharing A single computer processes the tasks of several users at different stations in round-robin fashion. Multiprocessing Processing done by two or more computers or processors linked together to perform work simultaneously. Two Approaches for Multiprocessing: Co processing One main CPU works together with other specialized microprocessors… like Math Coprocessor is present in every PC Parallel Processing Multiple CPU’s… Dual CPU PC’s etc The Operating System: What It Does Task Management Number of Users Number of Order of Processors Processing Multi-tasking One One Concurrently Multiprogramming Multiple One Concurrently Time sharing Multiple One Round robin Multiprocessing One or more Two or more Simultaneously Processing of two or more programs Formatting Initializing a disk - the process of preparing that disk so that it can store data or programs 4.3 Other System Software Device Drivers Utility Programs Device Drivers Specialized software programs that: (a) Allow input and output devices to communicate with the rest of the computer system. (b) Help the computer control peripheral devices. Peripheral Devices Peripheral, is a term used for devices, such as disk drives, printers, modems, and joysticks, that are connected to a computer and are controlled by its microprocessor. Although peripheral often implies “additional but not essential,” many peripheral devices are critical elements of a fully functioning and useful computer system. Few people, for example, would argue that disk drives are nonessential, although computers can function without them. Keyboards, monitors, and mice are also strictly considered peripheral devices, but because they represent primary sources of input and output in most computer systems, they can be considered more as extensions of the system unit than as peripherals. Utility Programs Also known as service programs, perform tasks related to the control and allocation of computer resources. They enhance existing functions or provide services not supplied by other system software programs. Among the tasks performed by utilities are the following: • • • • • • Backup Data Recovery Virus Protection Data Compression File defragmentation Disk Scanner Backup Utility Program which makes a duplicate copy of the information on your hard disk. If your hard-disk drive fails, and you have used a backup utility to make a backup, you can restore the information on your hard disk. Data Recovery Utility Program which restores data that has been physically damaged or corrupted. Data can be damaged by viruses, bad software, hardware failure, and power fluctuations that occur while data is being written/recorded Virus Protection Utility – Antivirus software A program that scans hard disks, floppy disks, and memory to detect viruses. A virus consists of hidden programming instructions that are buried within an applications or systems program. Fortunately, antivirus software is available. Antivirus software is a utility program that scans hard disks, floppy disks, and memory to detect viruses. Some utilities destroy the virus on the spot. Others notify you of possible viral behavior. Data Compression Utility A program which removes redundant elements, gaps, and unnecessary data from a computer’s storage space. As you continue to store files on your hard disk, it will eventually fill up. Data compression utilities remove redundant elements, gaps, and unnecessary data from a computer’s storage space so that less space (fewer bits) is required. File Defragmentation Utility Fragmentation - the scattering of portions of files about the disk in nonadjacent areas, thus greatly slowing access to the files Defragmenter utility program that finds all the scattered files on your hard disk and reorganizes them as contiguous files File Defragmentation Utility When a hard disk is new, the operating system puts files on the disk contiguously (next to one another). However, as you update a file over time, new data for that file is distributed to unused spaces. These spaces may not be contiguous to the older data in that file. It takes the operating system longer to read these fragmented files. A defragmenter utility program, commonly called a "defragger," will find all the scattered files on your hard disk and reorganize them as contiguous files. Disk Scanner & Disk cleanup Utility Detect and correct certain types of common problems on hard disks and floppies Search for and remove unnecessary files, such as temporary files. 4.4 Common Operating Systems for Various Platforms Platform - the particular processor model and operating system on which a computer system is based. Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Disk Operating System (DOS) The original operating system produced by Microsoft, which had a hard-to-use commanddriven user interface Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Macintosh operating system (Mac OS) Operating system which runs only on Apple Macintosh computers . First introduced in 1984, set the standard for iconoriented, easy-to-use graphical user interfaces. Mac OS X Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Microsoft Windows 3.1 & 3.X In the1980s, taking its cue from the popularity of Mac’s easy-to-use GUI, Microsoft began working on Windows--to make DOS more userfriendly. In 1992, Windows 3.1 emerged as the preferred system among PC users. Technically, Windows 3.1 wasn’t a full operating system; it was simply a layer or shell over DOS. Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Microsoft Windows 95, & 98 Later, Windows 3.1 evolved into the Windows 95 operating system, which was succeeded by Windows 98. Both having Plug and Play - the ability of a computer to automatically configure a new hardware component that is added to it Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Microsoft Windows Millennium (WinMe) Is the successor for home users to Windows 95 and 98, designed to support desktop and portable computers. Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Operating Systems Novell’s NetWare Windows NT/2000 Windows XP / Vista Unix Linux Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Operating Systems Novell’s Netware - a long popular network operating system for coordinating microcomputer-based local area networks (LANs) throughout a company or campus Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Operating Systems Windows NT - Microsoft’s multitasking OS designed to run on network servers; it allows multiple users to share resources such as data and programs Windows 2000 - successor to Windows NT Windows XP – Windows Vista Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Operating Systems Windows XP - Formerly code-named Whistler, Microsoft’s newest OS, which combines elements of Windows 2000 and Windows Me New GUI featured in Windows XP Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Operating Systems UNIX was initially developed by AT&T’s Bell laboratory in 1969 as operating system for minicomputers. UNIX - a multitasking operating system for multiple users with built-in networking capability and versions that can run on all kinds of computers. Variants of Unix for Internet:• Sun Microsystems’ Solaris • Berkeley Software Distribution (BSD) Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Operating Systems Linux – an Open Source free version of UNIX, with continual improvements resulting from the efforts of tens of thousands of volunteer programmers Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Operating Systems Open-source software software which any programmer can download from the Internet for free and modify with suggested improvements Linus Torvalds, creator of Linux Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Operating Systems for Handhelds Palm OS - the dominant OS for handhelds, which runs the Palm and Handspring Visor, and is licensed to other companies, such as IBM and Nokia. Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Operating Systems for Handhelds Windows CE/Pocket PC--Microsoft Windows for handhelds: In 1996, Microsoft released Windows CE, a greatly slimmed-down version of Windows 95 for handheld computing devices, such as those made by Casio, Compaq, and HewlettPackard. Windows CE had some of the familiar Windows look and feel and included rudimentary word processing, spreadsheet, e-mail, Web browsing, and other software. Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. 4.5 The OS of the Future: “The Network is the Computer” Dot Net – .Net is Microsoft’s platform for an OS for the entire Internet, designed to link unrelated websites so that people can organize all info in their lives using PCs and smaller devices Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. The OS of the Future E-speak - H-P’s version of an Internet OS, or “universal language,” that allows different websites to communicate with one another Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. The OS of the Future Jini - Sun Microsystems’ software designed to let all types of electronic gadgets on a wired or wireless network communicate with one another. Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. The Opposite Possibility: No One Company Dominates Distributed system - a non-centralized network consisting of several computers and other devices that can communicate with one another Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. 4.6 Online Software & Application Software Providers: Turning Point for the Software Industry? ASP (Application Service Provider) - a firm that leases software over the Internet to customers. Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Computers Revisited: “Thin Clients” versus “Fat Clients” Thin client - users download not only data but also different kinds of application software from an online source Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc. Network Computers Revisited: “Thin Clients” versus “Fat Clients” Fat client - users provide their own software and are usually responsible for any upgrades of hardware and software Data can be input or downloaded from online sources. From ERP to ASP: The Evolution of “Rentalware” ERP (Enterprise resource planning) software - large client/server software applications that help companies organize and operate their businesses Copyright © 2003. Exclusive rights by The McGraw-Hill Companies, Inc.