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Chapter 2 INTRODUCTION OF SYSTEM & APPLICATION SOFTWARE Dr. BALAMURUGAN MUTHURAMAN 2015-2016 1 OPERATING SYSTEM (OS) An operating system, or OS, is a software program that enables the computer hardware to communicate and operate with the computer software. Without a computer operating system, a computer would be useless. A collection of programs which control the resources of a computer system Written in low-level languages (i.e. machine-dependent) An interface between the users and the hardware When the computer is on, OS will first load into the main memory 2015-2016 2 BASIC FUNCTIONS OF THE OPERATING SYSTEM Device configuration Controls peripheral devices connected to the computer File management Operating System Transfers files between main memory and secondary storage, manages file folders, allocates the secondary storage space, and provides file protection and recovery Memory management Allocates the use of random access memory (RAM) to requesting processes Interface platform Allows the computer to run other applications 2015-2016 3 OTHER FUNCTION OF OPERATING SYSTEM • Best use of the computer resources • Provide a background for user’s programs to execute • Display and deal with errors when it happens • Control the selection and operation of the peripherals • Act as a communication link between users • System protection 2015-2016 4 TYPES OF OPERATING SYSTEM »Graphical User Interface (GUI) »Multi-user »Multiprocessing »Multitasking 2015-2016 5 GUI - Short for Graphical User Interface, a GUI Operating System contains graphics and icons and is commonly navigated by using a computer mouse. Multi-user - A multi-user operating system allows for multiple users to use the same computer at the same time and different times. 2015-2016 6 Multiprocessing - An operating system capable of supporting and utilizing more than one computer processor. Multitasking - An operating system that is capable of allowing multiple software processes to run at the same time. 2015-2016 7 SYSTEM SOFTWARE The programs and the file that comprises the operating system are called system software. These files include configuration files, system preferences, system services, libraries of functions and the drivers for the hardware installed on the computer. Once you install the operating system, the system software is also installed. Program such “Software update” or “Windows update” can be used to update the system software. 2015-2016 8 APPLICATION SOFTWARE The subclass of a computer program which utilizes the capabilities of computer is called application software. Application here means the application software and the implementation. The example of application software programs includes media players, spreadsheets and word processors. When multiple applications are packaged together then it is called application suite. 2015-2016 9 There is a common user interface in each application suite which makes it easier for the user to learn different applications. In some cases, such as Microsoft Office, the various application programs have the ability to interact with each other. This facility is very handy for the user. For example, a user can insert the spreadsheet in a word processor using the application software. Application software cannot run without the presence of system software. 2015-2016 10 DIFFERENCE BETWEEN SYSTEM SOFTWARE AND APPLICATION SOFTWARE • System software gets installed when the operating system is installed on the computer while application software is installed according to the requirements of the user. • System software includes programs such as compilers, drivers, assemblers while application software includes media players, word processors, and spreadsheet programs. 2015-2016 11 • Generally, users do not interact with system software as it works in the background whereas users interact with application software while doing different activities. • A computer may not require more than one type of system software while there may be a number of application software programs installed on the computer at the same time. • System software can run independently of the application software while application software cannot run without the presence of the system software. 2015-2016 12 Data Base Management Systems (DBMS) • A database is a collection of information categorized by specific fields. Databases are usually searchable by keywords. • A collection of related electronic records in a standardized format, searchable in a variety of ways, such as title, author, subject, and keyword. 2015-2016 13 DEFINITION -DBMS A Database Management System (DBMS) is a set of computer programs that controls the creation, maintenance, and the use of the database of an organization and its end users 2015-2016 14 Example of DBMS A database is any organized collection of data. Some examples of databases you may encounter in your daily life are: – a telephone book – T.V. Guide – airline reservation system – motor vehicle registration records – papers in your filing cabinet – files on your computer hard drive. 2015-2016 15 Purpose of DBMS Keep records of our: Clients Staff Volunteers To keep a record of activities and interventions; Keep sales records; Develop reports; Perform research Longitudinal tracking 2015-2016 16 Drawbacks of using file systems to store data: – Data redundancy and inconsistency • Multiple file formats, duplication of information in different files – Difficulty in accessing data • Need to write a new program to carry out each new task – Data isolation — multiple files and formats – Integrity problems • Integrity constraints (e.g. account balance > 0) become part of program code • Hard to add new constraints or change existing ones 2015-2016 17 Why Use a DBMS? • • • • • Data independence and efficient access. Reduced application development time. Data integrity and security. Uniform data administration. Concurrent access, recovery from crashes. 2015-2016 18