week 3

               In this week, I learnt about the role of computer software which includes Software layers, Programming language and Standard Software Packages. Before I post these all topics, let me share some ideas about what software is. A software is an intengible part of a computer which tells what a computer supposes to carry out and how to do it. There are 3 types of software :

• System software
• Application software
• Programming language

System software

Application Software

Software Layers

In software layer, there are 4 steps between computer user and computer hardware. They are Application, Operating system, Device drivers, System software (BIOS). 

Application Program

It is the upper most software layer where normal computer interactions occur word processing, email, internet and so on. It is easy to use. 

Operating System 

It receives order from the user via application program. It has programs and routine that control all access to hardware. When it determines its safe to proceed, direct calls to device drivers are performed. 

Device drivers

They are very low level instructions to a device. For e.g, the printer or the hard drive. It can provide interface or communication directly with hardware devices.  

System software (BIOS)

It is the part that typically involved Basic Input and Output System. It support common activites that high level application need to do. e.g, printing. There are 2 types of system software. They are:

1. Operating System
2. Utiltiy Program

Operating system :  a set of programs that coordinates all the activities among computer hardware resources. 

Utility programs  a set of programs that allows a user to perform maintenance-type tasks concerning the computer itself, its devices and its programs.

Programming Language

A set of words, abbreviations, and symbols that enables a programmer to communicate instructions to a computer. Types of programming language are :

• Low level language –A Machine-dependent language. Each instruction represents a single machine instruction.

• High level language- Machine independent language. Each instruction represents several machine instructions. 

There are 2 types of low level language namely, 

• Machine language
• Assembly language

Machine Language

Assembly Language

Compiling

Some programs are translated using a compiler. When programs are compiled, they are translated all at once.Compiled programs typically execute more quickly than interpreted programs, but have a slower translation speed.

Interpreting

Some programs are translated using an interpreter. Such programs are translated line-by-line instead of all at once (like compiled programs). Interpreted programs generally translate quicker than compiled programs, but have a slower execution speed.