The Components of System Software. The three basic components of system software are the operating system, device drivers, and utility programs. An operating system is the principal component of system software. Device drivers allow input/output devices to communicate with the rest of the computer system. Utility programs provide functions (such as disk cleanup and data recovery) not supplied by other system software.
The Operating System: What It Does. The operating system (OS) consists of the master system of programs that manage the basic operations of the computer. Features of the OS are booting, user interface, CPU management, file management, task management, formatting, and security management. (1) In booting, the OS is loaded into the computer's main memory. (2) The supervisor or kernel manages the CPU. The OS also manages the memory by partitioning, dividing the memory into foreground/background areas, and arranging the programs to be processed, in a queue. (3) In file management, the OS records the storage location of files. (4) Task management includes multitasking, which executes more than one program concurrently; multiprogramming, which concurrently executes programs of different users on a multiuser operating system; time sharing, which refers to a round-robin processing of programs of several users; and multiprocessing, which is simultaneous processing of two or more programs by multiple computers. (5) Formatting, or initializing, consists of preparing a disk to store data or programs. During formatting, concentric circles called tracks are recorded on the disk. On a formatted disk, each track is divided into sectors. Intersections of tracks and sectors are used to store address references. (6) Security management allows users to control access to their computers.
Other System Software: Device Drivers & Utility Programs. Device drivers are specialized software programs that allow input and output devices to communicate with the rest of the computer system. Utility 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. Tasks performed by utilities include the following: (1) A backup utility is used to make a duplicate copy of the information on your hard disk. (2) A data-recovery utility is used to restore data that has been physically damaged or corrupted. (3) The antivirus software is a utility program that scans hard disks, floppy disks, and the memory to detect viruses. (4) Data compression utilities remove redundant elements, gaps, and unnecessary data from a computer's storage space so that less space (fewer bits) is required to store or transmit data. (5) Fragmentation is the scattering of portions of files about the disk in nonadjacent areas, thus greatly slowing access to the files. A defragmenter utility program will find all the scattered files on your hard disk and reorganize them as contiguous files. (6) The Disk Scanner utility program detects and corrects certain types of common problems on hard disks and floppies and also searches for and removes unnecessary files.
Common Operating Systems. There are three categories of platforms, or particular combinations of processors and OSs, for desktops/notebooks, for networks, and for handhelds.
The principal desktop/laptop OSs are DOS, Macintosh OS, and the Microsoft Windows series. DOS was Microsoft's original OS. The Macintosh operating system runs only on Apple Macintoshes. Microsoft Windows 95/98 and more recently Windows Me are popular for desktops and portables. The recently released Microsoft Windows XP targets home and small business users; XP is based on Windows Me and Windows 2000. Microsoft introduced a new version of Windows 2000 called the Windows Server 2003 family. This version includes the Microsoft .NET Framework, a means for building, distributing, and maintaining web services and applications.
Principal network server OSs are NetWare from Novell; Windows NT and its successor Windows 2000 from Microsoft; Unix, available in several versions, including Sun's Solaris and BSD; and Linux, a free version of Unix and a kind of open-source software modifiable by anyone.
Principal OSs for handhelds are Palm OS, which runs the Palm and the Visor, and Windows CE (a slimmed-down version of Windows 95), which became Pocket PC, a simpler version.
The OS of the Future. A distributed system is a noncentralized network of several computers and other devices that can communicate with one another.
Open-source software is gaining ground in three important areas: (1) Countries in Asia, Europe, and Latin America – including China and Germany—are now encouraging government agencies to use open-source software, particularly Linux. (2) Small companies, such as California guitar, and Zumiez, have opted to use Linux because it allows them to exclude certain programs, such as word processors or web browsers that are not an option with Microsoft. (3) Schools are able to link old PCs to a Linux server, thus making word processing, spreadsheets, slide presentations, email, calendaring, and web-browser programs available for free.
