SOFTWARE

SOFTWARE

A set of instructions is called a programme. Software refers to set of computer programmes(or) A set of programmes that logically inter linked together is called software.Software is ofter divided into application programme and system programme. Basically there are 3 types of software’s

1.System software

2.Application software

3.General purpose software

System Software: System software is computer software, designed to operate the computer hard ware and to provide and maintain a platform for running application software.

System software helps use the operating system and computer system. It includes.

1. Utilities

2. Language Translators

3. Programming languages

4. Device Drivers

5. Utilities

6. Language Translators

Dos (Disk Operating System) windows are some of widely used system software’s.

Programming Languages: Programming languages are vocabulary and set of grammatical rules for instructing a computer to perform a specific task. The term programming language refers to high level languages, such as BASIC, C,CPP, COBOL, FORTRAN, ADA & PASCAL. High level languages were simple compared to human languages are more complex than the languages the computer actually understands machine level languages.

Machine Language or First Generation Languages:

Machine level language is the language of the computer. The only language the computer understands without translation programmes written in machine level language can only be used on the computer model for which the language is written.

Note: Writing programmes is machine level language is not only difficult for humans to do but also it is subjective error, because the instructions were codified in series of 1’s and 0’s

Advantages: 

Very fast execution because no transaction program me is required for the CPU.

Disadvantages:

1. It is very difficult to program me in machine  language because the programmers has to know details of  hardware components to write program me.
2. The programmer has to remember a lot of codes which results in programme errors.
3. It is difficult to de-bug the programme.

Assembly Language (or) Second Generation Language: It is also known as symbolic (or) mnemonics languages because they employ symbols for both arithmetic and logical operations and even location addresses, because of the mnemonic symbols it become easy to the programmers to do tasks greatly.

Note: But the computer follows its machine language only and the programme written programme written in assemble languages has to be translated. The translator is known as assembler.

Advantages:

1. Easier to understand and saves a lot of time and effort of the programmer.
2. Easier to correct the errors and modify it.
3. Assemble language has the same efficiency of the execution as the machine level language.

Disadvantages:

1.      A programme written for one computer might not run in another computer with different hardware configuration.

2.      The programme has to write large number of statements to perform a task.

3.      It is not for generalaised application software’s

Translators:

There are three types of translators to translate high level language into machine level language.

     1.Compiler

     2. Interpreter

     3. Assembler

Compiler: The compiler languages are also known as high level languages or producer languages. The compiler is an at once translator. It compiles the entire programme and displays the errors.     

 Interpreter: It is a line by line translator, it translates programme into machine level language line by line.

Example: COBOL

Assembler: Assembler is a translator mainly used for assemble level language where mnemonics are used, the assembler translates into machine level language.

Differentiate between third generation and Fourth generation languages:

Third Generation	Fourth Generation
Used by professional programmers	End user as well as professional programmers
Requires specification of how to perform the tasks	What task to perform
Difficult to read, understand and maintain	Easy to understand because of English like commands
Difficult to learn	We can learn quickly
Difficult to de-bug	Easy to de-bug
Typically file oriented	Typically data base oriented

Object Oriented languages: With traditional programming approaches the programme may be hundreds of lines long and can take years to complete often poor, productivity of programmers is low and programmers are usually behind schedule. When programme modifications are needed the code must be re-written and tested. As programmes become longer and more complex  achieving a reasonable quality level becomes a task. In order to solve these type of problems a new way using an object oriented languages. An object oriented programming an object OS written for each specific tasks and saved in a library, so that anyone can use. Object oriented programming are combined and a small amount  of code necessary for finishing the programme is done. Object can be modified, re-issued, copied are created. When an object is updated the entire programme is automatically updated.

Ex: C++, visual basic and java.

Operating system: Operating system acts as an interface between user and hardware. It is a system and considered to be back bone of the computer.

Functions of Operating System: There are 6 basic functions that an operating system can peroform.

Maintain System Security: They may requires users to enter a password. It identifies users as being authorized t have access to the system.

Schedule Jobs: Depending on the priorities, sequence of jobs are executed.

Hardware and software management: They can first the users application programme to be executed by loading it into primary storage and them cause the various hardware units to perform as specified by the application.

Multi-user resource sharing: They can handle the scheduling and execution of the application programmes for many users at the same time. A feature called Multi programming.

Handling Interrupts: An interrupt is the technique used by the OS to temporarily suspend the processing of one programme in order to allow another programme to may executed.

Maintains usage records: They keep track of the amount of time used by each user for each system unit, the CPU, secondary storages, input and output devices.

Various Types of Operating Systems:

Micro-Soft Disk Operating System: MS-DOS is a non graphical command line operating system created for IBM compatible computers that way first introduced by Micro soft in August 1981. It is a single user operating that run one programme at a time.

OS/2: In 1987, IBM and Micro-Soft announced a new Personnel Computer Operating System called OS/2 (operating system-2) unfortunately the original os/2 way not very successible, because it is unable to support many existing pc( personal computer) applications.

Micro-Soft windows:

1.     It is one of the most popular operating system because of graphical user interface features(GUI features)

2.     In this system, we can click on Icons with mouse button rather than writing the command as in MS-DOS.

3.     Simple and user friendly, quite animated and attractive, multi tasked features.

Flavours of windows operating system: Micro- Soft windows operating systems were developed for the home users and other has been for the professional IT users. There are 2 types of OS home version and professional version.

Windows-95: It is 32 bit OS way released in August-1995. It took Microsoft three and a half years to develop. It is a multi tasking environment, allowing the user to run multiple programmes or execute designed for easy  access to network resources. 

Windows-NT: “NT” means New Technology. IT is developed for the use of industry standard

1)    Stable multi tasking environment

2)    Enhance security features

3)    Increased memory

4)    Network utilities

             Windows-2000: Windows XP, windows vista etc

UNIXOS: UNIX is a computer OS originally developed by a group of AT and Telegraph employs at USA( American Tele Communications and Telegraph). UNIX environment of the internet and the re-shaping of computing as centered in networks rather than in individual computers. It is re-written in “C” language.

Linux is a graphical based but UNIX is a command based OS.UNIX is seen as an operating system on a work station or a network server.

1.      Portable

2.      Multi-user

3.      Hierarchical file system

4.      Inter process communication

Mac OS: It is a graphical user interface based operating system developed by Apple incorpation.

A macintosh user experience is credited with popularizing and graphical user interface.

Linux OS: Linux is the generic name for UNIX like OS that can be used on a wide range of devices from  super computer to wrist watches. Linux kernel is released and an open source license, so anyone can read and modify it’s code.

Features of operating system: Large centralized systems often support multiple simultaneous uses, hence this computing configuration requires an operating system that enables many users to concurrently share the central processor, the inter-leaving techniques commonly used are multi programming, multithreading, multitasking, virtual memory, multi-processing and time sharing.

Multi-Progamming: Multi programming is defined as execution of two (or) more programmes that all reside in primary memory since CPU can execute only one instruction at a time it cannot simultaneously execute instructions come two or more programmes. However it can cxecute instructions from one programme then from second programme then from first again and so on. This type of processing is refered to as concurrent execution.

Buffering: Buffering enables the processor to exeute another instruction while input or output taken place rather than and every sub task is assigned a thread, all the threads run concurrently.

Multi-tasking: The ability to execute  two or more of a single users tasks concurrently, it is an opposite contrast of single user operating system.

Single user:Single user operating system allows the user to work on one task at a time but multi- tasking operating system provide single user with multi- tasking capability.

Ex.OS/2 ,Unix, Zenix and Machitosh.

Virtual Memory: A programme by to take into account the size of the memory to fit all these instruction has to use the concept of virtual memory. If there is no space in Random Access Memory, if the user trying to run one or more programme, the primary memory took the help of secondary memory.

Ex: the few pages are in primary memory the computer system starts processing the programme, if the computer needs a page, it brings the page from secondary memory. It over writes it into the memory. Occupied by a page, it no longer needs. This is known as “overlying”.

Multi-Processing: The term multi-programming is sometimes loosely interchanged with the term multi processing, but they are not same. Multi programming involves concurrent execution of instructions from tow or more programmes sharing the CPU by one super. Multi processing  refers to the use of two or more central processing units link together to perform co-ordinate work simultaneously.

Time-sharing: The time-sharing is a methodology created to satisfy the processing needs of multi-programming and batch processing system. In time sharing systems the execution time is divided into small slots called Time slice, each process is processed for a time- slice and then the other process is taken for processing. This process goes on till all jobs are processed. Each user feels like the processor is dedicatedly processing his job only.

Device Drivers: Device Drivers are small files that act as an interface between hardware in a computer system and the operating system. the hardware requires device drivers, so that the OS can see the devices and handle them effectively and efficiently. A driver, typically communicate with the device through the computer bus or communication sub system to which the hard ware connects. When a calling programme invokes a routine in the driver that driver issues commands to the device.

Ex: Graphic cards, audio card, wireless cards etc.

Utility Programmes (or ) service programmes:

Utility programmes ( or) system programmes that perform general system support tasks. These programmes are provided by computer manufacturers to perform task that are common to all data processing

The following tasks are performed by the utility programmes.

      1.Sorting and storing the data.

      2.Checking or scanning the data stored on hard disk for security reason.

      3.Partitioning of drive.

      4.Performing routine data management tasks, such as deleting, re-naming copying and moving etc.

There are 3 types of utility programmes found in most computer systems

1.      Sort utilities

2.      Text editors

3.      Spooling software’s

Sort utilities: Sorting utility programmes are those that sort data, for example: A file of student records, we can sort by name, date of birth etc.

Spooling software: (simultaneous peripheral operation online)

The purpose of spooling software, is to compensate for the speed diffences between the computer and its peripheral devices. The spooling software is usually encountered in large system and network computing environments. The computer would be horrible bottle system and network computing environments. The computer would be horribly bottle necked, if it had two weights for slow input and output devices before it could resume processing. The computer from being slow down by input and output devices many computer system employ spooling software, these programmes takes the results of computer programme and move from primary memory to secondary storage device (disk). The area on the secondary storage device where the programme results are sent is commonly call the output spooling area now the out put device will interact the disk but not CPU.

Text editors: Text editors are programmes that allow text in a file to create and modify.

Ex: word processor

Disk copy programme: Allows and user to copy the entire content of one files from one diskette to another diskette.

Disk formatting programme: Allows and user to prepare a new blank disk by deleting already existing data (0r) from new diskette.

Fill deletion programme: Allows an user to delete a file stored on a diskette.

Fill viewing programme: Used to view the contents of a file on the display screen.

Directory programme: It allows an user to view name of the data and programme files which are stored on the diskette.

De-bugging programme: Usually written and provided by the computer manufactures. They assist in programme debugging means rectifying the errors.

The above are the few utilities.

Language Translators:

      1. Compiler

      2. Interpreter

      3. Assembler

A language Translators or language processor is a general term used for any assembler, compiler and interpreter. That accepts statements in one language and produce equivalent statements in another languages. The  three most widely used language translators are compiler, interpreter and assembler.

Compiler: A compiler translates the entire programme into machine language before the programme is executed. Compiler is most commonly used software to translate high level language such a FORTRN, C and PASCAL into low level language.

The compilation of programme is called “ Source programme” (or) “source module” Translation of programme to object modules of any sub programmes that must be used to complete processing. The resultant programme ready for execution is called “load programme” (or) “load module”.

General purpose: This software provides the frame work for a great number of business,scientific and personal applications. Spread sheet, data base, computer aided design(CAD) and word processing software etc.

Most general purpose software is sold as a package.

There are three basic types of software’s i.e, commercial, shareware and open software.

Commercial Software: Commercial software’s are comes free packaged and is available from software stores and through the internet.

Shareware Software: A software developed by individual and small companies that cannot afford to market their software world wide(or) by a company  that wants to lease a demonstration version of their commercial product.

Open Source Software: These software’s are designed and created by generous programmers and

         Release onto the public domain for public use. These are usually a copy right notice that must remain with the software product. Many popular open source applications are being developed and updated regularly by individuals and compiles that believe in the open source concept.

Word Processor: This is one of the general software application for editing, formatting and possibly printing. It consists a pre- defined tools like cut, copy, paste, bold, italic, underline, font size and font face, left align ,right align and justification etc.

Spread Sheet Programme: This software is generally suitable for accounting and financial purpose. It consists of columns and rows together make up a grid each cell consists of alpha numeric test, numeric’s numeric values (or) formula defines how the content of that cell is to be calculated. From the content of any other cell each time any cell is updated.

Data Base Management System: A data base management system is a software to manage a data base and run operations on the data requested by numerous.

Internet Browser: A browser is an  software application that enables and user      to display  and interact with text, images and other information typically located on a web-page at a web-site on the world wide web.

Ex: Internet explorer, Mozilla Firefox, Hot Java, Google chrome.

Electronic Mail: E-mail is method of composing, sending, storing and receiving messages over electronic communication system. We can send mail from one place to another with the high speed and less cost electronically. The term E- mail applies both to the internet E-mail system based on Simple Mail Transfer Protocol( SMTP).

Application Software: Application software is a computer software, designed to help the user to perform single (or) multiple tasks.

Ex: Accounting software, Graphic software and media players. If the capabilities of a computer directed to task that the user wishes to perform. A power plant merely generates electricity, itself really of any use until to a application like the electronic light which performs a service that the user desires.

ERP( Enterprise Resource Plan): Integrate all data and processes of an organization into single unified system. A typical ERP system will use multiple components of computer software and hardware to achieve the integration. The term ERP originally implied systems designed to plan utilization of enterprise wide resources.ERP systems typically attempt to cover all basic functions of an organization regardless of thee organizations business (or) chapter. An ERP system is a software package generally utilize non-profit organizations, governments and other large entitles.

Decision support system(DSS): A decision support system is a information processing system frequently used by accountants, managers and auditors to assist them in the decision making process. Advances in hardware technology, interactive computing design, graphic capabilities and programming languages contributed to this cvolution. Decision. Support system has achieved broad use in accounting and auditing today.

Characteristics of Decision Support System(DSS): Decision support system supports decision management making decision support solve relatively unstructured problems.

Components of decision support system.

The user, the data base, planning language

User: The user of a decision support system is usually a management an unstructured (or) semi-structured problem to solve. User does not need a computer background to use a decision support system for problem solving. The most important knowledge is a thorough understanding of the problems and the factors to be considered in finding a solution.

Data base: DSS includes one (or) more databases. The databases contain both routine and non routine data from both internal & external sources.

Ex: About economic conditions, market demand, goods (or) services and industry competition.

Planning languages: Two types of planning languages that are commonly used in DSS.

I.      General purpose planning languages

II.      Special purpose planning languages

General purpose planning language: Allows user to perform many routine tasks.

Ex: Spread sheets.

These languages enable user to tackle to broad range of budgeting, forecasting and other worksheet oriented problems.

Special purpose planning languages: These are used for certain jobs Ex: SAS, SPSS

These languages are more limited, basically used for statistical analysis

Model Base: The planning language in a decision support system allows the user to maintain a dialogue with the model base. The model base is a brain the decision support system because it performs data manipulations and computations with the data provided to it by the user and the data bases. Some of the model bases are cross tabulation, regression analysis, time series analysis, linear programming and financing computation.

Examples of decision support system in accounting:

Cost accounting system: Managing costs in this industry requires controlling cost of supplies, expensive machinery, technology and variety of personnel. DSS can accumulate these product costs to calculate total cost per patient, if you take and example of health.

Artificial intelligence: It  tries to emulate aspects of human behavior such as reasoning, communicating, seeing, and hearing. There are several types of artificial intelligence including National language, voice and visual recognition, robotics, neural network and expert systems.

Definition: “ Artificial intelligence is study and design of intelligent agents where an intelligent is a system that perceives its environment and takes action that maximize its  chances of sources. It is a science and engineering of making intelligent machines”.

Expert systems: Expert systems are used for complex or unstructured tasks that require experience and specialized knowledge, narrow specific subject areas to make decisions, comparable to those of an expert.

Knowledge base: It includes the data, knowledge, relationships and decision rules used by experts to solve a particular type of problem. A knowledge base is a computer equivalent to all the knowledge and insight that and expert or a group of experts develop through years of experience in their world.

Inference engine: This programme contains the logic and reasoning mechanism that simulates the expert logic process and deliver advice.

User interface: This program allows the user to design, create, update, use and communicate with arrive at expert system.

Explanation facility: It provides the user with an explanation of the logic, the expert system used to arrive at its conclusion.

Knowledge acquisition facility: The knowledge engineer is responsible for extractive and individuals expertise and using the knowledge acquisition facility to enter it into the knowledge base.

Expert system offers the following benefits:

1.      They can increase productivity.

2.      They provide a cost effective, alternative to human experts.

3.      They produce better quality and more consistent decisions.

4.      They are faster and more consistent and do not get distracted over corked(or) stressed out.