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Basics of Computers System S/W

Basics of Computers System S/W

As you learn, system software acts as an interpreter for the hardware system underlying this. We'll cover some relevant applications for the system in-depth here.

Operating System

Computer operating system ( OS) is the lifeline. You attach all the basic devices, such as CPU, monitor, keyboard, and mouse; put in the power supply, and turn it when you know you've got already. Yet the computer won't function or come to life because it has an OS built in it.

  • Keeps all hardware components available to follow user instructions
  • Coordinates between various system
  • Schedules multiple tasks according to priority
  • Allocates resources to individual tasks
  • Allows computer access to network
  • Enables people to use app features and use it
  • In addition to initial booting, these are some of the operating system functions−
  • Administration of computer resources such as hardware, software, shared resources etc.
  • Resource Allocation
  • Preventing software errors
  • Control improper usage of computers

MS-DOS, created by Microsoft for IBM PC, was one of the first operating systems. This was the Command Line Interface (CLI) OS which revolutionized the PC market. Owing to its interface, DOS was difficult to use. The users needed instructions to remember to do their tasks. Microsoft created Graphical User Interface ( GUI) based Software named Windows to render computers more open and user-friendly, which changed the way people used computers.


Assembler is a framework software that translates assembly-level and machine-level code programs.

These are the benefits of assembly level programming −

  • Improves programmer 's performance, because it is simpler to remember mnemonics
  • Productivity improves as the number of errors reduces and the debugging time accordingly
  • Programmer has exposure to hardware resources and thus has flexibility in creating programs customized to the particular comput


The main advantage of assembly level language has been the ability to maximize the usage of memory and hardware. However computers had more memory and better hardware components with technological advances. Therefore the simplicity of writing programs was more essential as memory and other hardware resources became configured.

Furthermore, a need was felt to take programming from a handful of trained scientists and computer programmers, so computers could be used in more areas. This contributed to the creation of high-level languages which were simple to understand due to commands similarity with English.

The system software used for the line-by-line transcription of high-level language source code into machine-level language object code is called an interpreter. Through line of code is taken by an interpreter and converted to machine code and placed in the object file.

Use an interpreter has the benefit that they are very simple to write and do not need a huge memory space. The use of interpreters, however, has a major disadvantage, i.e., interpreted programs take a long time to execute. To overcome this limitation, compilers were developed particularly for large programs.


System software that collects, scans, translates the whole application into object code and then generates an executable file that is called a compiler. Compilers compete unfavorably to interpreters on the face, as they–

Compiled programs run very rapidly on computers, though. The image below illustrates the step-by-step method of converting source code into an executable file-

Those are the stages in executable code compiling −

  • Are more rigorous than interpreters
  • Need more space on memory
  • Taking any extra time to compile source code
  • Pre-processing − Pre-processor instructions, typically used in languages such as C and C++, are interpreted at this point, i.e. they are transformed to assembly line language.
  • Lexical analysis − All instructions here are converted to lexical units such as constants, variables, symbols of the arithmetic, etc.
  • Parsing − All commands are checked here to see if they conform to the language's grammar rules. If errors occur, the compiler may ask you to fix them before you can continu
  • Compilation − The source code is converted to object code at this stage.
  • Link − When there are links to external files or repositories, their executable addresses should be applied to the program. Even, whenever the code has to be rearranged for actual execution, reconfiguration should be made. The final output is the executable file, ready for execution.