31-07-2012, 02:27 PM
Computer software
[attachment=29713]
Definition : The set of instructions used to control hardware and accomplish specific tasks are called software.
Functions :
Manage the computer resources of the organization.
Develop tools that human beings can utilize to take the advantage of these resources.
Act as an intermediary between stored information and organization.
Note : Earlier user interface used to be treated as the third layer of software category. Now is a part of application software.
Different types of software's can be illustrated as
System software :
Definition : A software that directly interacts with the hardware and comprise programs that manage the hardware components.
Functions
Supervises the execution of all application software
Convert high-level and 4GL programming codes into computer executable form.
Manages resources like storage and memory, peripheral devices like printer and monitor etc. Ex : operating system.
Functionalities may be single-tasking or multi-tasking.
Application software
Definition : Program that help the user, the system software and the hardware to work together to solve the end user problems.
Special software languages are used to develop application software.
Ex : Word processing software
Can be purchased in stores and is called packages.
Custom software : A software designed and written based on situation.
Free ware : Available in public domain and can be used and altered without fee and restriction.
Shareware : Author of the software assumes voluntary contribution from the user.
Public domain : no copyright.
Open source :
Software generations
First generation : Used machine language.
Second generation : Assembly language. (used mnemonic codes)
Third generation : High level languages like FORTRAN and COBOL. Program need to be compiled using compiler.
Fourth generation : Packaged software.
Languages like C, object oriented languages like c++ and java, WWW and development of GUI.
Fifth generation : Integrated software, animation, multimedia. NLP (natural language processor), HTML, XML, Active X and Active server pages.
Operating system
Definition : Is a set of programs that controls and supervises a computer system’s hardware and provides service to application software, programmers, and users of a computer system.
Functions :
Allocation of resources to the application jobs in the execution queue.(resource management)
Provides locations for data and programs in main memory and controls input and output devices.(memory management)
Free space management, disk scheduling and storage allocation. (Secondary-storage management)
Schedules the jobs submitted.(process management)
Provides a pleasant and effective user interface. ( command interpreter system)
Types of operating systems
Single user system :
Allows one program to be executed at a time.
Often found in personal computers. Ex:Microsoft’s windows.
Multiprogramming system :
Permits multiple programs to share system’s resources through concurrent usage of CPU.
Programs appear to be executed simultaneously.
Increases the overall performance of the CPU.
CPU devotes time to processing instructions from one program while another goes through I/O operations.
Time-sharing system :
Allows multiple users to access a single computer system.
CPU shifts among users on a timed basis, by allocating specific periods of time and it appears as each user has uninterrupted access to the CPU.
When an interrupt occurs, the OS may switch to another program before a full time slice is used.
Multiprocessing system :
Allows simultaneous execution of programs by a computer that has two or more CPU’s.
Mainframe and supercomputers.
A single large main CPU may be connected to multiple channels which handles input and output from the main CPU and coordinates the work of slower I/O devices.
Virtual-Storage System :
Developed after some limitations was faced in multiprogramming.
Secondary memory as an extension of primary storage.
Gives an illusion of having maximum amount of primary memory.
Portions of a program can be swapped between primary and secondary storage devices.
Paging is another extension of this concept, where pages are kept on secondary storage devices in and out of primary storage as needed.
Virtual machine (VM) :
Is a very powerful program that can run several operating systems at one time.
Allows several users of a computer system to operate as if each had the only terminal attached to the computer.
The user can select the OS which compatible with the intended application.
Types of information processing
Batch processing : Data is collected and stored before processing.
Real-time processing : Transactions are processed on a real time basis. Ex : All internet based transactions. Railway or airline ticket booking.
Distributed processing :
Parallel processing :
Sequence scheduling : next program is selected based on priority.
Concurrent scheduling : Concurrent processing of two or more programs.
Types of Application s/w
Content access software
End-User software ( document mgmt, scheduling, accounting mgmt)
Enterprise software (SCM, CRM, product life cycle mgmt)
Simulation software
Examples of application software
Word processing software
Spread sheet software
Presentation software
Database software
Communication software
Accounting and financial software
Project management
Project management
Projects like developing of software, publishing a news letter, implementing a training programme, starting a new business or even building a new home are done by managers.
Project management software helps to put together a plan of action, compile and organise all details to be completed.
Ex : MS-project
[attachment=29713]
Definition : The set of instructions used to control hardware and accomplish specific tasks are called software.
Functions :
Manage the computer resources of the organization.
Develop tools that human beings can utilize to take the advantage of these resources.
Act as an intermediary between stored information and organization.
Note : Earlier user interface used to be treated as the third layer of software category. Now is a part of application software.
Different types of software's can be illustrated as
System software :
Definition : A software that directly interacts with the hardware and comprise programs that manage the hardware components.
Functions
Supervises the execution of all application software
Convert high-level and 4GL programming codes into computer executable form.
Manages resources like storage and memory, peripheral devices like printer and monitor etc. Ex : operating system.
Functionalities may be single-tasking or multi-tasking.
Application software
Definition : Program that help the user, the system software and the hardware to work together to solve the end user problems.
Special software languages are used to develop application software.
Ex : Word processing software
Can be purchased in stores and is called packages.
Custom software : A software designed and written based on situation.
Free ware : Available in public domain and can be used and altered without fee and restriction.
Shareware : Author of the software assumes voluntary contribution from the user.
Public domain : no copyright.
Open source :
Software generations
First generation : Used machine language.
Second generation : Assembly language. (used mnemonic codes)
Third generation : High level languages like FORTRAN and COBOL. Program need to be compiled using compiler.
Fourth generation : Packaged software.
Languages like C, object oriented languages like c++ and java, WWW and development of GUI.
Fifth generation : Integrated software, animation, multimedia. NLP (natural language processor), HTML, XML, Active X and Active server pages.
Operating system
Definition : Is a set of programs that controls and supervises a computer system’s hardware and provides service to application software, programmers, and users of a computer system.
Functions :
Allocation of resources to the application jobs in the execution queue.(resource management)
Provides locations for data and programs in main memory and controls input and output devices.(memory management)
Free space management, disk scheduling and storage allocation. (Secondary-storage management)
Schedules the jobs submitted.(process management)
Provides a pleasant and effective user interface. ( command interpreter system)
Types of operating systems
Single user system :
Allows one program to be executed at a time.
Often found in personal computers. Ex:Microsoft’s windows.
Multiprogramming system :
Permits multiple programs to share system’s resources through concurrent usage of CPU.
Programs appear to be executed simultaneously.
Increases the overall performance of the CPU.
CPU devotes time to processing instructions from one program while another goes through I/O operations.
Time-sharing system :
Allows multiple users to access a single computer system.
CPU shifts among users on a timed basis, by allocating specific periods of time and it appears as each user has uninterrupted access to the CPU.
When an interrupt occurs, the OS may switch to another program before a full time slice is used.
Multiprocessing system :
Allows simultaneous execution of programs by a computer that has two or more CPU’s.
Mainframe and supercomputers.
A single large main CPU may be connected to multiple channels which handles input and output from the main CPU and coordinates the work of slower I/O devices.
Virtual-Storage System :
Developed after some limitations was faced in multiprogramming.
Secondary memory as an extension of primary storage.
Gives an illusion of having maximum amount of primary memory.
Portions of a program can be swapped between primary and secondary storage devices.
Paging is another extension of this concept, where pages are kept on secondary storage devices in and out of primary storage as needed.
Virtual machine (VM) :
Is a very powerful program that can run several operating systems at one time.
Allows several users of a computer system to operate as if each had the only terminal attached to the computer.
The user can select the OS which compatible with the intended application.
Types of information processing
Batch processing : Data is collected and stored before processing.
Real-time processing : Transactions are processed on a real time basis. Ex : All internet based transactions. Railway or airline ticket booking.
Distributed processing :
Parallel processing :
Sequence scheduling : next program is selected based on priority.
Concurrent scheduling : Concurrent processing of two or more programs.
Types of Application s/w
Content access software
End-User software ( document mgmt, scheduling, accounting mgmt)
Enterprise software (SCM, CRM, product life cycle mgmt)
Simulation software
Examples of application software
Word processing software
Spread sheet software
Presentation software
Database software
Communication software
Accounting and financial software
Project management
Project management
Projects like developing of software, publishing a news letter, implementing a training programme, starting a new business or even building a new home are done by managers.
Project management software helps to put together a plan of action, compile and organise all details to be completed.
Ex : MS-project