Computer and Computer system are two different things.The word computer refers to that bare electronic device, which posses computing power ,using which wide variety of operation are performed ,while computer system refers to group of items , which put together make computerization of an application possible .
Computer system are comprises of Five major parts-:
The physical part of computer system is referred to as hardware.All electronic and mechanical items that constitute Computer system fall in to the category of hardware.For example keyboard,mouse,moniter, printer, processor etc are hardware.Power and capabilities of power directly govern the power of Computer system.
Any instruction ,which either makes hardware perform a task or ready for performing the task is called Software.For example ,just by switching on the computer and pressing the keys of keyboard , computer will not accept the data from you.Prior to that ,it will require a set of instructions ,which would gear up the hardware internally ,to accept the data.
Based upon the tasks performed by the software ,softwares are broadly classified in to categories-:
All those instructions,which computer uses either for its activation or internal resource management are called system software.For example ,software that would transfer the data/ instructions from keyboard to computer’s memory will be system software.Similarly the software that would make the processor run and do the calculatons or print the result of calculations on printer /monitor will also fall in to the category of sytem software.
Those instruction which are given to the computer for automating a manual task ,are called application software.For example ,instructions for adding two matrices ,finding sum of given Geometric Progression(GP) series ,calculating income tax for all the employees of an organization ,booking air tickets etc are examples of applications software.
Application Software is either developed using special packages or special computer languages that are developed for this purpose.
Special software development packages like MS-office,Core1Draw ,Photoshop,Flash , 3-D Studio Max etc are the packages that are developed to automatic specific type of task.
There are many activities ,which don’t fall within the scope of readymade software ,For such activities custom built software need to be developed .custom built software is developed ,using computer languages like C,C++,python,java etc.
The software that is built in to hardware is called Firmware.For example ,in computer system ,few special instructions called bootstrap instructions( software )are written( with the help of special devices )within an electronic chip (hardware)called Read Only Memory(ROM) and this chip is integrated with the electronics of the computer system .This software basically reads the operating system,loads it into computer’s memory and makes the hardware functional .Note that bootstrap program is an example of Firmware as it alwys resides within the electronic chip.
Raw facts and figures are termed as Data.For example ,roll numbers,name ,address and marks of all the students studying in a class is data.
Data works as raw material for computer system .Computer system pocesses the data and brings out the hidden surprise element in it.For Example ,after processing student’s data a merit list may be prepared ,showing the roll number,names and marks of top 10 rankers .This list is surprise element that student is outstanding.Note that the details of these students were already in the data but were unnoticeable to the viewer.
Processing has brought them out and focused viewer’s attention on them.
In computer terminology ,processed data is called information and information is always useful for decision making .Thus ,it can be said that computer process the data and converts it in to information for decision making.
Persons who make use of computers are called users. No computer system is complete without user. From beginning to the end of automation process ,they require user intervention.
Users can be broadly classified in to two categories-:
Programmers are the users ,who use computer s to write programs.Those programmers who write system programs(system software)are called system programmers and those who develop application programs are called application programmers.
End Users -:
End users are the persons, who make use of computer hardware ,system software and application software for some specific purpose ,for which the application software was designed.For example ,the railway reservation clerks sitting at reservation counter and doing reservations for passengers are end users of railway reservation package.Similarly,
Basic structure of computer system and interaction of its basic parts is shown in figure .
Figure shows that user interacts with external world and gathers data.He enters the data in to the computer using software .This Software can either be application software or system software.
If ,required software interacts with firmware and passes the data to the hardware for further actions like processing ,storing or displaying etc .
For the sake of understanding the basic structure of computer system ,hardware can be broadly visualized as combination of two parts i.e. external hardware and internal hardware .
External hardware remains visible and accessible to the user directly.He may not require software to make use of it.For example ,he views the result of processing directly on the monitor screen or he hears the music directly from the speakers.
Internal parts of the hardware are enclosed within the computer chassis.For example processor, memory etc are not directly exposed to the user. He interacts with them through software .For example ,to store the data on some storage device ,he executes a suitable command (making use of software).