Basic Computer Architecture

Basic Computer Architecture
Modern-day computers follow the Von Neumann architecture, which was first published by John von Neumann in 1945. The basic architecture of a computer is as follows
  1. Input Unit
  2. Central Processing Unit = Control Unit + Arithmetic and Logic Unit (ALU)
  3. Memory Unit
  4.  Output Unit
  1. Input Unit:  They are the secondary storage devices that can be used to insert/read data or program into the main memory of the computer.
    • Example: Keyboard, Mouse, Trackball, Joystick, Scanners, Microphone, Webcam, Barcode readers, Touch Screen, Optical mark reader (OMR), Magnetic Ink Character Recognition (MICR), etc
    • Primary Input Device: Keyboard
  2. Central Processing Unit: It is the main processor that controls all data processing activities of a computer. It is known as the "Brain of the Computer." It stores data, intermediate results, and instructions (program). The CPU consists of two units
    • Control Unit: controls the data transfer and instructions among other units of a computer without involving in the data processing activities. It communicates with the input, output, and memory units by fetching codes for instruction.
    • ALU: Part of CPU that handles both arithmetic operations such as addition, subtraction, etc and the logical operations such as comparison and selection of data. 
  3. Memory Unit: It stores and supplies all the needed data, instructions, intermediate results, and programs on a priority basis for the proper functioning of a computer. 
  4. Output Unit: These devices are used to output the final result processed by the computer to the user.
    • Example: Monitor, Printer, Speaker, Plotter, Head Phone, Projector
    • Primary Output Device: Monitor

Language Processors

As it is difficult to read, write and understand data and instructions written in the machine language in the form of 0s and 1s, we needed something that enabled us to convert the program written in the high/low-level programming language to the machine language. With the intervention of the translator, it was made possible. 

A language processor is a special kind of program that has the ability of a translator to convert the program code into machine language. There are three different types of language processors. They are
  1. Compiler: converts high-level language to equivalent machine language.
    • Examples: C, C++, C#, Java, Pascal, COBOL, BASIC, Ada, D, DASL, Corba, BCPL, ALGOL, Corn, Delphi, Smalltalk, etc
  2. Assembler: converts low-level language/Assembly language to equivalent machine language.
  3. Interpreter: Similar to a compiler, it converts high-level language to equivalent machine language with a difference that it converts one line code at a time, checks for an error, then proceeds to the next line of code. Thus making it more efficient and faster than the compiler. 
    • Examples: Perl, Python, JavaScript, Lisp, PHP, VBScript, Matlab, etc


  • The brain of a computer is known as – CPU.  (Previous PSC Questions: Computer Grade II , 2016)
  • In Computer, Logical operations are performed by – ALU. (Previous PSC Questions: Secretariat Assistant, 2018)
  • Rearranging and allocating space in memory to provide for multiple computing tasks is called  – Memory Management. (SSC CGL, 2015)
  • What is the process of loading the operating system files into dynamic random access memory? Booting. (Previous PSC Questions:  Secretariat Assistant, 2015)
  • A computer program that is used to convert an assembly language to machine language – Assembler.  (Previous PSC Questions: University Assistant, 2016)
  • The translator program that translates each line of source program as it runs is called  – Interpreter.  (Previous PSC Questions: KSRTC, 2015)
Thanks for reading!!!