Wednesday, September 21, 2011

Packaged software

          An application package is a generalized set of program which can be used to deal with a particular application eg. producing bill or payroll. Package tend to be available for application which are common to many users. software houses produce application packages which they can sell to a  number of customers.


Advantages of packaged software
  1.  The user saves efforts money and time for solving problems.
  2. The user will get well tried and tested programs provided by reputed software vendors. 
  3. The package are relatively fast in work and easy to access.
  4. They are user friendly.

MODEM

MODEM means modulator and demodulator,In a data  communication system ,workstation and other remote input or output devices are linked with one or more processor to capture input data and receive output information . connecting equipment and software some time feferred to as interface elements are used to bridge the different operation environment of these input and output devices and processors.

Dos Tutorial

                         Every computer needs an 
operating system. Operating system 
controls all the computer equipment
and allows to check itself. DOS 
co-ordinates the computer system,
just as the conductor co-ordinate 
the orchestra. Your application 
programs run in concert with DOS, 
trusting it to keep the system humming.
DOS lets you control the things you care
about such as which program to run what 
report to print what disks to format or 
what files to erase. These functions 
share an important characteristic, the
disks and disk drives.
           There are two major types of
software They are system program which 
control the operation of the computer 
system and the application program which performs more obviously useful tasks, such as word processing , data base management spreadsheet, calculations etc. 
             The program user hardware. It must be able to receive instructions from the keybord. display and print results, read and write files from to a disk send and receive data through the computers communication connections change the colors on the color display, and so on through all the capabilities of the hardware.
             Each program doesn't have to perform all these functions for itself. A system program called the operating system manages the hardware, the operating system allows an application program to concentrate on what it does best, where it is moving paragraphs about, tracking account receivable bill or calculating stress in a bridge beam, etc. 

Introduction to QBASIC

                    QBASIC  is a programming language. Microsoft inc. has been releasing this programs development environment as a replacement for GBASIC and BASICA. The environment includes a full screen , syntax checking editor, multi-file and multi-windows editing, full debugging facilities, pull down menus and a simple yet powerful menu structure that can be driven either through the keyboard or using a mouse. Once you are in the Qbasic development environment through the keyboard or using mouse. The following basic features have enhanced the capabilities of QBASIC:
  • Subprograms allow you to separate programs into individual and logically independent modules. 
  • Structured programming supports is provided in the form of multi line IF..THEN..END type flow control structures like WHILE...WEND, SUB, FUNCTION procedures . 
  • Alphanumeric labels can be used making the programs more readable and writeable , because Qbasic does not require line numbers for its programs statements. 
  • Dynamic arrays can be declared to optimize memory usage.
  • Large numeric arrays are allowed and any number of 64 K arrays can be used and fit into available memory.
  • Metacommands allow you to control the way the compiler interprets and compilers your program.
              The Qbasic interpreter has a simple user interface and menu structure. Its design serves to aid the user in developing programs with the least number of steps. The intelligent editor checks syntax as the program line are entered. The program is compiled as it is typed allowing the program to be run in a single step. Errors are identified and reported in a convenient way that allows the user to correct them immediately.  

HTML and Web page desigining

                      The shared language of Communication of the world wide web was developed in Switzerland. This has four official languages it was difficult for people to communicate without a common language in computers. They developed a language some what similar to Esperanto ( which is combination of different languages of Europe) named Hyper Text Markup Language HTML.
         HTML allows to format text, add rules, graphics, sound and video and saved it all in a text only in ASCII file that any computer can read. The key to HTML is in the tags, the keywords enclosed in less than and greater than signs that indicates what kind of content is coming up. 
          HTML looks like a lot of text sprinkled with greater than and smaller than signs until you open the file with a special program called a browser. A browser can interpret the HTML tags and then show the formatted document on the screen. 
         The main or the key ingredient of the HTML is its Hypertext . HTML document can contain links to other HTML documents or practically anything else in the Internet. you can create several web pages and have your cursor jump from one to another as required . you can also create links to other organizations web pages giving your users access to information held at other sites.

System Development Cycle

                      The system development life cycle is classically thought of as the set of activities that analysts, designers ans users carry out to develop and implement an information system. the system development life cycle consists of the following
activities:
  • Problem definition
  • System analysis
  • System design
  • Programming analysis 
  • Program preparation band Testing
  • Implementation, Evaluation and Maintenance.
Problem defination
             To create a new system of programms or to improve or modify an existing one people have to recognize that a problem or need exists at the very beginning. 
        This problem or need may result from changing operating conditions. Managers, employees of departments  affected by changing conditions, and data processing personnel often participate in requirement sessions until the problem has been defined and specified study goals have been outlined. These goals should then be put in writing and approved by all concerned . This step cannot be by passed. 
       In this session, the requesets are clarified and then technical feasibility, economic feasibility operational feasibility study  are made., After a project request is approved its cost priority completion time and personnel requirements are estimated and used to determine where to add it any existing project list. 
                    

System study

                  System study is derived from the Greek word systema. which means an organized relationship among the functioning units or components. In our daily life, we have come in contact with the transposition system and for over three decades, the computer system. when we talk about computer systems they are categorized in the following groups for purpose of study:
  • Physical or abstract system.
  • Open or closes system.
  • Deterministic or probabilistic systems. 
  • Man made information system. 
          We are more concerned about man made information system and we will discuss about it in the coming sections; The man made informantion system is further classified as:
  • Formal information systems
  • Informal information systems
  • Computer based information systems
            The third category of information system depends mainly on the computer for handling business applictions . system analysis develop several different types of information system to meet a variety of busuness needs . There is a class of systems collectively known as computer based information system. 
           As we have different types of transportation systems such as highway systems railwazy shstens and airlines systems  computer based information systems are of too many types. They are classified as:
  • Transaction processing system
  • Management information system
  • Decision support systems
  • Office automation systems