Computer System System Software

Learning Objective Students should understand the different types of systems software and their functions. Students should be able to give a brief account of the basic functions of an operating system and be aware of the common types of operating system. Students should demonstrate a basic understanding on what utility programs are and how they are used.

3 System Software System software is a generic term referring to any computer program or library whose purpose is to (help) run the computer system (including low-level software implementing computer networks). An operating system and Utility Software are examples. If system software is stored on non-volatile storage such as integrated circuits, it is usually termed firmware. System software contrasts with application software, which are programs that help the end-user to perform specific, productive tasks, such as word processing or image manipulation.

4 Operating System An operating system (OS) is a software program that manages the hardware and software resources of a computer. A key component of system software, the OS performs basic tasks, such as controlling and allocating memory, prioritizing the processing of instructions, controlling input and output devices, facilitating networking, and managing files.

5 Application Programs Operating System Hardware Compiler Text editor ………. Database system User 1User 2User n

6 Functions of the OS Process management Memory management Disk and file systems Networking Security Device drivers Graphical user interfaces

7 Process management Old OS (e.g. MSDOS) allows one process to be run at a time Modern operating systems are able to simulate execution of many processes at once (multi-tasking) even under a single CPU multi-tasking is accomplished by simply switching processes quickly

8 Memory management Nowadays most of the computer's memory is arranged in a hierarchical manner, starting from fastest registers, cache, RAM, disk storage, and perhaps even magnetic tape. The memory manager in a OS coordinates the memories by tracking which one is available, which is to be allocated or deallocated and how to swap between the main memory and secondary memories.

9 Disk and file systems Operating systems have a variety of native file systems (e.g. windows : NTFS, FAT, FAT32, Linux: ext2, ext3, Google: GFS) Reading, writing and managing these file system is the job of OS

10 Networking Most operating systems are capable of using the TCP/IP networking protocols. One system can appear on a network of the other and share resources such as files, printers, and scanners.

11 Security Security as it pertains to the operating system is the ability to authenticate users prior to access, categorize the level of access the user has, and limit access based on a policy placed by administration. Firewall is the front line of security A software firewall is configured to allow or deny traffic to a service running on top of the operating system.

12 Device drivers A device driver is a specific type of computer software developed to allow interaction with hardware devices. Drivers are used for interfacing with: Printers Video adapters Network cards Sound cards

13 Graphical user interfaces Most modern operating systems contain Graphical User Interface. GUIs tend to change with time. For example, Windows has modified its GUI every time a new major version of Windows is released.

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24 Difference version of Windows XP "Windows XP Home Edition", for home desktops and laptops (notebooks) "Windows XP Home Edition N", as above, but without a default installation of Windows Media Player, as mandated by a European Union ruling "Windows XP Professional Edition", for business and power users "Windows XP Professional Edition N", as above, but without a default installation of Windows Media Player, as mandated by a European Union ruling

25 Difference version of Windows XP Windows XP Media Center Edition (MCE), released in November 2002 for desktops and notebooks with an emphasis on home entertainment Windows XP Media Center Edition 2003 Windows XP Media Center Edition 2004 Windows XP Media Center Edition 2005, released on October 12, "Windows XP Tablet PC Edition", for tablet PCs (notebooks with touch screens)

26 Difference version of Windows XP Windows XP Embedded, for embedded systems "Windows XP Starter Edition", for new computer users in developing countries Windows XP Professional x64 Edition, released on April 25, 2005 for home and workstation systems utilizing 64-bit processors based on the x86 instruction set (AMD calls this AMD64, Intel calls it Intel EM64T) Windows XP 64-bit Edition, is a version for Intel's Itanium line of processors; maintains 32-bit compatibility solely through a software emulator.

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30 Examples of OS Unix-like (e.g. Solaris, Linux, FreeBSD, Mac OSX) Microsoft Windows (e.g. WinCE, Win2K, WinXP, Windows Vista) Others (e.g. Palm OS, OS/2, OpenVMS, BeOS)

31 Utility Programs Utility software is a type of computer software that is designed to help manage and tune the computer hardware, operating system or application software and perform a single task or a small range of tasks. Utility software has long been integrated into most major operating systems.

32 Example of Utility software Disk defragmenters. (e.g. diskeeper) Virus scanners (Norton Anti-virus) Binary/Hex/Text Editor (Notepad) Compress and decompress (WinRAR, WinZip) Encryption