Computer science thesis, Thesis of Applications of Computer Sciences

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Computer Fundamentals

Unit-IV

Mrs. Kiran Bala Dubey Assistant Professor Department of Computer Science Govt. N. P. G. College of Science, Raipur

Contents

• System Software
  • System s/w Vs Application s/w
  • Type of system s/w
  • Introduction & Types of OS
  • Boot loader
  • Diagnostic programs
  • BIOS
  • Utility programs
• Application Software
  • Microcomputer s/w
  • Interacting with the system
  • Trends in PC s/w
  • Type of Application s/w
  • Differences between program & packages Languages Definition Generations of computer languages Type of languages Language processors : Assembler, Interpreter & Compiler Linker & Loader Program constructs Algorithm & Flowchart

Types of system software -

• Operating system – It takes care of effective and efficient utilization of all hardware and software components of a computer system. Example - DOS, WINDOWS, UNIX.
• Programming language translators – It transform the instructions prepared by programmers in a programming language into a form that can be interpreted and executed by a computer system. Example- Assembler, Compiler & Interpreter
• Communication Software – In a network environment communications software enables transfer of data and programs from one computer system to another.
• Utility Programs- It is a set of programs that help user in system maintenance tasks and in performing tasks of routine nature. Example- Format, Backup, Restore, Zip, Unzip & Anti virus

Introduction & Types of OS

• An Operating System is the interface between the computer hardware and the end-user. Processing of data, running applications, file management and handling the memory is all managed by the computer OS.

4. Distributed Operating System - When two or more systems are connected to each other and one can open files which are not present in their system but in other devices connected in the network. - Its usage has now increased over the years. - They use multiple central processors to serve real-time applications. - Failure of one system does not affect the other systems connected in the network. 5. Embedded Operating System - These special Operating systems are built into larger systems - They generally are limited to single specific functions like an ATM. 6. Network Operating System - They have one main server which is connected to other client servers - All the management of files, processing of data, access to sharing files, etc. are performed over this small network - It is also a secure operating system for working with multiple users. 7. Mobile Operating System - With the advancement in the field of technology, smart phones now are released with an Operating system. - They are designed in a manner that they can help a small device work efficiently.

8. Multi user operating systems - It allows a number of users to work simultaneously on a single computer system. These types of operating systems are specially designed for the multi user system. - Examples of multi user operating systems includes Unix, Linux and Windows 2000. 9. Multitasking operating systems - It allows a user to give multitask at a same time on a single computer system. - multitasking operating system are also known as multiprocessing operating system and multiprogramming operating system. - The number of tasks processed simultaneously by this operating system is depending upon speed of CPU, the capacity of memory and size of programs. - Examples of multitasking operating systems includes Unix, Linux, Windows 2000, windows XP and windows 10. 10. Multiprocessor operating system

• It allows the computer system to use more than one CPU in a single system for executing more than one or multiple processes at a time.
• A computer system having multiple CPU process faster than a system which contains a single CPU.
• Examples of multiprocessor operating systems are Linux, Unix, windows 2000 etc.

Diagnostic programs

• A diagnostic program is a software tool used to diagnose problems with a particular set of hardware devices. It can be used by a trained technician or by the owner of the device, to identify and resolve hardware issues.
• Diagnostic programs ideally provide the user with guidance regarding any issues or problems found during its operation.

BIOS

• BIOS (basic input/output system) is the program in a ROM chip found on motherboards that uses to start the computer system after it is powered on. It also manages data flow between the computer's operating system (OS) and attached devices, such as the hard disk, video adapter, keyboard, mouse and printer.
• The main use of BIOS is to act as a middleman between OS and the hardware they run on.

Application Software

Application software is a set of one or more programs designed to solve a specific problem or task. Example Payroll processing system, Exam result processing system, Ticket reservation Software, word processor, a spreadsheet, an accounting application, a web browser, an email client, a media player, a file viewer, a console game, or a photo editor. etc. Types of application software –

• Pre-written Application Software
• User specific Application Software

Differences between program & packages 1.Programs are set of instructions to perform a task. 2.These are one piece of software. 3.Programs are something that provide instruction to computer to perform particular task.

1. Program is especially developed by highly skilled programmer i.e. single programmer.
2. Programs are easy to develop and requires less time as compared to packages i.e. few hours or minutes. 1. Packages are set of software programs. 2. These are multiple pieces of software. 3. Packages are something that is packed. 4. It is a special method of distributing and installing software to computer. 5. Package is especially developed by group of programmers i.e. more than one programmer and require more time to develop than program i.e. weeks or months.

Languages

• The first generation languages , or 1GL , are low-level languages that are machine language.
• The second-generation languages , or 2GL , are also low- level assembly languages. They are sometimes used in kernels and hardware drives, but more commonly used for video editing and video games.
• The third-generation languages , or 3GL , are high-level languages, such as C, C++, Java, JavaScript, and Visual Basic.
• The fourth-generation languages , or 4GL , are languages that consist of statements similar to statements in a human language. Fourth generation languages are commonly used in database programming and scripts examples include Perl, PHP, Python and SQL.
• The fifth-generation languages , or 5GL , are programming languages that contain visual tools to help to develop a program. Examples includes Mercury, OPS5, and Prolog.

Linker & Loader

In execution of the program, major role is played by two utility programs known as Linker and Loader.

1. Linker : A linker is special program that combines the object files, generated by compiler/assembler, and other pieces of codes to originate an executable file have. exe extension. In the object file, linker searches and append all libraries needed for execution of file. It regulates memory space that code from each module will hold. It also merges two or more separate object programs and establishes link among them. 2. Loader : The loader is special program that takes input of object code from linker, loads it to main memory, and prepares this code for execution by computer. Loader allocates memory space to program. Even it settles down symbolic reference between objects. It in charge of loading programs and libraries in operating system.

Program constructs

• Programs are designed using common building blocks. These building blocks, known as programming constructs (or programming concepts), form the basis for all programs.
• There are three basic building blocks to consider:-
  • sequence is the order in which instructions occur and are processed
  • selection determines which path a program takes when it is running
  • iteration is the repeated execution of a section of code when a program is running
  • There are two types of iteration:
    • definite iteration (also known as count-controlled iteration)
    • indefinite iteration (also known as condition-controlled iteration)
• All programs use one or more of these constructs. The longer and more complex the program, the more these constructs will be used repeatedly.