What is System Programming,OS,System software,Application software,System call & kernel

What is System Programming,OS,System software,Application software,System call & kernel

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[I]System Programming & Application programming

• Systems programming, or system programming, is the activity of programming computer system software.
• The primary distinguishing characteristic of systems programming when compared to application programming is that application programming aims to produce software which provides services to the user directly (e.g. word processor)
• systems programming aims to produce software and software platforms which provide services to other software.Systems programming requires a great degree of hardware awareness. Its goal is to achieve efficient use of available resources.
• System software is the layer between the hardware and application software; It controls the hardware, and provides services to applications.

Examples of system software:

1. Operating systems 
2. Assemblers (like GNU AS, NASM, FASM, etc...).
3. Macro Processors 
4. Linkers and Loaders (like GNU ld which is part of GNU binutils).
5. Compilers and Interpreters (like gcc and python).
6. Debuggers (like gdb).
7. Text editors (like vim).

Depending on the level of language used there are different types of application software:

• 1) Word processing software. ...
• 2) Spreadsheet Software. ...
• 3) Desktop Publishing Software. ...
• 4) Database Software. ...
• 5) Communication Software. ...
• 6) Presentation Software. ...
• 7) Internet Browsers. ...
• 8) Email Programs.

[II]Operating System

• As the name suggests it is the users interface to the machine. It allows you (provides you a means) to operate/use the machine.
• Since computer is a very complex and sophisticated machine we cannot use it as easily we use other mechanical machines, like a fan. To operate a fan all we need is a single button called regulator. So the regulator is the OS of a fan.
• But to operate a complex device like computer we need a complex software called OS. The Windows start menu is the point from where you start interacting/operating/using your computer. Hence Windows is your OS for your computer.

An operating system is a collection of software that manages computer hardware resources and provides a common services for computer programs.The operating system is vital component of the system software in a computer system.

• operating system manage the computer ‘s hardware resources.
  1)Input devices such as a keyword and mouse.
  2)Output devices such as display monitors,printers,and scanners.
  3)Network devices such as modems,routers and connections.
  4)storage devices such as internal and external drives.

[III]Kernel

• Kernel is present in different devices like desktop computers,laptops,mobile,tablet etc.in your mobile also u can check version and anme of kernel
• It is software program,It acts as bridge between all of your applications and hardware as a controller.
• Kernel makes/helps  the software to interact with hardware and grt the work done.
• A kernel is a central component of an operating system. It acts as an interface between the user applications and the hardware. The sole aim of the kernel is to manage the communication between the software (user level applications) and the hardware (CPU, disk memory etc). The main tasks of the kernel are :
• Process management
  Device management
  Memory management
  Interrupt handling
  I/O communication
  File system... Etc

[IV] System Call

• For performing any operation a user must have to request for a service through service call,which is called as system call
• typically writtten in various HLL
• It is one of the way to request service from Kernel
• Commands or Instructions used to request services from kernel is called System calls.

Generally OS works in Two different Modes:

A] User Mode:-When any application stats running it is considered to be in user mode 

Ex:-Reading contents on word documents,browser etc.

B]Syste or Kernel Mode:Once application or process request harwware through kernel we enter into kernel mode

Ex:Requesting printing of documents i.e need to request to h/w printer.

[V] Process

A process is a series of steps and decisions involved in the way work is completed.