What is Components of a Computer System?

Components Of a Computer System

The basic architecture of a computer system can be divided into two major components each doing a separate but inter-linked function. The components are listed below:

1) Hardware

2) Software

1- Hardware-

Physical and tangible parts of a computer system are called hardware. Computer is a collection of several different parts like Input Devices, Microprocessor (CPU), Memory and Output Devices.

1.1- Input Devices-

An input component in a computer system is concerned with the data that is fed in. With the help of these components, data is actually entered into the computer. Several input devices can be used to enter data. These devices use a variety of technologies ranging from a key pressed to voice. The input components have evolved from switches that were used in the first generation computers to the more modern and sophisticated voice recognition systems. The keyboard and the mouse are good examples of input components.

1.2- Memory & Storage Devices-

During the process of processing data. the data needs to be stored in the computer. It is also necessary to store the programs that will manipulate the data in order to generate the output, which will also be stored. The storage components deal with the storage of programs and data. Computer’s memory can be visualized as a contiguous block of rectangular holes. Memory is of two kinds:

1.Primary Memory-

Primary Memory is volatile. That is, they can store data as long as they are supplied with electricity. They are used for temporary storage of data. It is also called the main memory or the central memory. it can be categorized into two types:

  • RAM (Random Access Memory): It is temporary in nature. During the execution of program the data required by the program is stored in RAM. it provides a volatile storage.
  • ROM (Read Only Memory): It is permanent in nature. The programs which are always required for running the machine are stored in ROM. It provides a volatile storage. ROM is available in various categories:
    • PROM (Programmable Read Only Memory)
    • EPROM (Erasable Programmable Read Only Memory)
    • EEPROM (Electrically Erasable Programmable Read Only Memory)

2. Secondary Memory

Secondary storage components, on the other hand can store data permanently. The secondary memory is the external memory. External memory can be used for read and write operations. Secondary memory can be either in the form of a Hard disk, Floppy Disk or CDROM.

Measurement Unit of Memory

Data given by the user is either decimal numbers or alphabets. so, a step of conversion is necessary before the inputs get accepted by the computer. Number and alphabets get converted into binary digits(BITS). Bits are the digital electronic pulses (on / off) that are generated for the conversion of data. Memory is measured in terms of BYTE. 0 & 1 are called bits. These bits are combined in various combinations for creating the digital from of data.

Dictionary of BITS and BYTE

8 Bits = 1 Byte

1024 Bytes = 1 Kilo Byte (KB)

1024 KB = 1 Mega Byte (MB)

1024 MB = 1 Tera Byte (TB)

1.3- Output Devices

The computer, after processing the data, generates an output. This output can be in the from of plain text, printouts, graphs etc. For this purpose, the output devices are used. various types of output devices are available in the market today. They use a variety of technologies to generates specific types of outputs. For instance, plotters are used for outputting engineering and other precision drawings, printers are used to generate letters, bills etc. and the Visual Display Unit (VDO) is used to view the output.

1.4- Basic Architecture of Computer (CPU)

The CPU (Central Processing Unit) has major component. The input components are denoted by Input. They are used to give the inputs in the form of program and data to the computer, which are stored temporarily in the primary storage and if necessary they are also stored permanently in the secondary storage. The primary and the secondary storage are the storage components. The next step is to carry the inputs to the ALU (Arithmetic and Logic Unit) where the data is processed according to the program fed.

The ALU sends the processed output back to the primary storage from where, if necessary, it is sent to the secondary storage. The output is also sent to the output devices, marked as Output. These devices signify the output is also sent to the output devices, marked as Output. These devices signify the output components.

The Major function of the control unit, thus, is to provide an environment where all the other units can function by interacting and exchanging with each other.


A program is a set of instructions that are arranged in a sequence that guide the computer to solve a problem. The computer needs processing instructions to be given to it for performing the computations. These sets of programs are know as Software. Software can be divided into two categories.

  1. System Software
  2. Application Software

2.1- System Software-

The system software is concerned with making a computer work and understands the user given data. instruction to process data for providing the needed information. System Software has following components:

2.1.1- Operating System

Operating System is System Software, which acts as an interface between the user and the computer hardware. In other words we an say that it manages all the operation of the system and provide a bridge between user and hardware. an operating system is an important component of a computer system which controls all other components of the computer system. Operating System controls and coordinates the use of the hardware among the various application programs for the various users. Operating system is also act as a Resource Allocator and Control Program. These components are:

  1. Hardware : It provides the Computer resources.
  2. Applications Program Routines: It defines the way in which the computing resources are used to solve the computing problems of the user.
  3. Users: They are the users who uses all components.
Functions of Operating System
  • Program Execution
  • Handing Input/output operating
  • Manipulation of Files System
  • Error detection and Handling
  • Resource Allocation
  • Accounting
  • Information and Resource Protection
Types of operating System
  1. Multi programming: It offers a more efficient approach to increase system performance. In order to increase resource utilization, system supporting multiprogramming approach allows more than job (Program) to utilize CPU time at any moment.
  2. Multi tasking: A running state of a program is called as a process or a task. A multi tasking operating system (also called multi processing operating system) supports two or more active process simultaneously.
  3. Network Operating System: In network operating system, the users are aware of existence of multiple computers and can log in to remote machine and copy files from one machine to another machine.
  4. Single User Operating System: It allows a single user to work on a computer at a time. Example: MSDOS, Windows-98 etc.
  5. Multi User Operating System: it allows simultaneous access to a computer system through two or more terminal Example: UNIX, LINUX, Windows- NT/2000/XP etc.
2.1.2- Computer Languages & Languages Processors

Instructions that are used to control the computer are known as Computer Language. These are a collection of rules and instruction that helps in Programming. Following types of computer languages are used for programming.

  • Machine or Low Level or Binary Language – There is only one language understood by the computer with out using a translation program. This language is called machine language or machine code of computers. Machine code is the fundamental language of computer and normally is written in binary from i.e. 1 & 0.

Advantages: Efficiency at time, Simplicity of instructions

Disadvantage: Each machine has its one code, Machine code is difficult to run, Time consuming to write, Very difficult to make changes

  • Assembly Language – Assembly language was developed in 1950. This language uses easily understand able symbols to represent instructions. A program called ASSEMBLER is used to convert this language into machine language.

Advantages: By the use of MNEMONICS (symbols) the task of programmer is made easier than using language, The insertion and deletion are quite easy, modification of program is easier then machine, the human effort to write a program is much less compared to machine language.

Disadvantages: Low Level Language, Non standardization of assembly languages, less efficient than machine languages

  • High level language

High level language are written in narrative from which is easier to understand, write and modify. This narrative form uses a restricted set of natural words to which very specific meanings are assigned. It written in English but has its own syntax.

There are a number of high level languages available for programming:

BASIC (Beginners all Purpose symbolic Instruction code), FORTRAN (Formula Translation), COBAL (Common Business Oriented Language), C, C++, JAVA etc.

  • Language Processors

Language processors are the system software that is used to convert or translate the programs written in high level language or assembly language to machine language. The following types of translators are available;

  • Assembler- These are used to convert assembly language programs to machine language.
  • Compiler- These are used to convert high level language programs to machine language, whole program at a time like C++, JAVA etc
  • Interpreter- These are used to convert high level language programs to machine language, one line at a time like BASIC, LOGO etc.

2.2- Application Software-

The software, which has been developed for a specific application, is categorized as application software. Application software can be placed in following categories:

  • Word Processors : Microsoft Word, PageMaker, Wordpad
  • Spreadsheets : Microsoft Excel, Lotus
  • Presentation : Microsoft PowerPoint
  • Databases : Microsoft Access, SQL, Oracle
  • CAD/CAM : AutoCAD
  • Accounting : Tally, Busy etc.
  • Internet Browsers : Microsoft Internet Explorer, Netscape Navigator
  • Animation : Maya, Flash, Dream Weaver etc.


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