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  • 1. UNIT: II I. COMPUTER SOFTWARE The term software refers to set of computer programs, procedures and associated programs, documents describing the programs and how they are used. A software package is a group of programs that solve a specific problem or performs a specific type of job eg: a word processing package may contain programs for text editing, formatting, drawings, graphics,etc. hence,a multipurpose computer syatem has a several software package one each foe each type of job it can perform.APPLICATION & SYSTEM SOFTWARESoftware refers to a collection of programmes & associated documents.There are two types of software:- o System Software: It is a set of 1 or more programs, which controls the operation &/or extends the processing capability of a computer system. It makes the operation of a computer system more effective & efficient. It helps hardware components work together & provide support for the development & execution of application software (programs).Good system software enables development & execution of application packages on a computer system with less time & efforts. A computer without some kind of system would be very ineffective & most likely impossible to operate. Programs included in a system software package are called system programs & programmers who prepare system software are referred as system programmer. o Application Software: It is a set of 1 or more programs, which solves a specific problem, or does a specific task. Programs included in an application software package are called application programs & programmers who prepare system software are referred as application programmer. 1. PROGRAMMING LANGUAGES AND THEIR SOFTWARE A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely. o Object-Oriented Programming Languages: 1
  • 2. Known as the newest and most powerful paradigms, object-orientedprogramming requires the designer to specify the data structures as wellas the types of operations to be applied on those data structures. Thepairing of data, and the operations that can be done on it is called anobject. A program made using this language is therefore made up of a setof cooperating objects instead of an instructions list. The most famousobject-oriented programming these days are C#, C , Visual Basic, Java,and Python. o Structured Programming Languages:An exceptional type of procedural programming, structured programmingprovides programmers with additional tools to handle the problemscreated by larger programs. When using this language, programmers arerequired to cut program structure into small pieces of code that caneasily be understood. Instead of using global variables, it employsvariables that are local to every subroutine. Among the popular featuresof structured programming is that it doesnt accept GOTO statementwhich is usually associated with the top-down approach. Such approachstarts with an opening overview of the system with minimal details aboutthe various parts. To add these details, design iterations are thenincluded to complete the design. Commonly used structured languagesinclude C, Pascal, and ADA. o Procedural Programming Languages: Procedural Programming involves a list of operations the program needs to complete to be able to attain the preferred state. It is a simple programming paradigm where every program comes with a starting phase, a list of tasks and operations, and an ending stage. Also called imperative programming, this approach comes with small sections of code that perform certain functions. These sections are made up of procedures, subroutines, or methods. A procedure is made up of a list of computations that should be done. Procedural programming lets a part of the code to be used again without the need to make several copies. It achieves this by dividing programmatic tasks into small sections. Because of this, programmers are also capable of maintaining and understanding program structure. Among the known procedural languages are BASIC and FORTRAN. 2. ASSEMBLERS, COMPILERS & INTERPRETERS 2
  • 3. o Assemblers: For an assembly language, a computer program to translate between lower-level representations of computer programs. An assembler converts basic computer instructions into a pattern of bits which can be easily understood by the computer and the processor can use it to perform its basic operations. o Compilers: A compiler is a computer program (or set of programs) that transforms source written in a programming language (the source language) into another computer language (the target language, often having a binary form known as object code). The most common reason for wanting to transform source code is to create an executable program. The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a lower level language (e.g., assembly language or machine code). If the compiled program can run on a computer whose CPU or operating system is different from the one on which the compiler runs, the compiler is known as a cross-compiler. A program that translates from a low level language to a higher level one is adecompiler. A program that translates between high-level languages is usually called a language translator, source to source translator, orlanguage converter. A language rewriter is usually a program that translates the form of expressions without a change of language. o Interpreters: An interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language. An interpreter may be a program that either Executes the source code directly translates source code into some efficient intermediate representation (code) and immediately executes this explicitly executes stored precompiled code made by a compiler which is part of the interpreter systemOPERATING SYSTEMSMeaningOperating system is a integrated set of programs that control theresources (cpu,i/o devices etc. ) of a computer system and provides itsusers with an interface or virtual machine that is easier to use than thebare machine. it has two main objectives :-1) make a computer system easier to use 3
  • 4. 2) manage the resources of computer system.7. TYPES OF OPERATING SYSTEMS Batch Processing Operating System:In a batch processing operating system interaction between the user and processor is limited or there is no interaction at all during the execution of work. Data and programs that need to be processed are bundled and collected as a batch and executed together. Multi-Tasking Operating System:In this type of OS several applications maybe simultaneously loaded and used in the memory. While the processor handles only one application at a particular time it is capable of switching between the applications effectively to apparently simultaneously execute each application. This type of operating system is seen everywhere today and is the most common type of OS, the Windows operating system would be an example. Real-time Operating System:A real-time operating system processes inputs simultaneously, fast enough to affect the next input or process. Real-time systems are usually used to control complex systems that require a lot of processing like machinery and industrial systems. Single User Operating System:A single user OS as the name suggests is designed for one user to effectively use a computer at a time. Multi-User Operating System:This type of OS allows multiple users to simultaneously use the system, while here as well, the processor splits its resources and handles one user at a time, the speed and efficiency at which it does this makes it apparent that users are simultaneously using the system, some network systems utilize this kind of operating system. Distributed Operating System:In a distributed system, software and data maybe distributed around the system, programs and files maybe stored on different storage devices which are located in different geographical locations and maybe accessed from different computer terminals. 4
  • 5. DBMSCOMPONENTS OF DATABASE SYSTEMA database system is composed of four components; Data Hardware Software Users1. Data - It is a very important component of the database system. Mostof the organizations