Course 150 Basic Computing Environment

Objective of course Familiar with Linux environment Objective of lecture: To understand basic terms like software, programming language and tools (compiler,interpreter).

Books Bhattacharya, Mauro, Mamone, Kapil Sharma, Thomas, Whiting, Gundavaram, “Beginning Red Hat Linux”, Wrox Neil Mathew & Richard Stones, ‘Begining Linux Programming’, Wrox Press Andrew Evans, Neil Mathew & Richard Stones, ‘Instant Linux/Unix’, Wrox Press Author: Christopher Negus, Title: Fedora 9 & Red Hat Enterprise Linux Bible,Publishers: Wiley,Year of Publication:2004 Ellen Siever, Aaron Weber, Stephen Figgins Linux in a NutShell, O Reilley & Associates, Red Hal linux Unleashed Matchtel Garless, Introduction to Linux: A Beginner;s Guide, Fultus Technical Library Shell programming by Yashwant Kanetkar Unix shell programming in 24 hours SAMS publication

Concept of Software Types of Software :Application Software, System Software. Concept of Programming Languages: High Level and Low Level Compiler, Interpreter, Editors, Operating System.

Software Software is set of instructions that performs a specific task. Software is intangible

Application Software an application is a computer program designed to help people perform a certain type of work. word processors, spreadsheets, media players and database applications. application suite – package of applications

Examples Documentation Data Management Financial Software Reservation systems Classroom Management Education Software Video games Media players Web browser Vehicle simulators Animation software

System Software It is any computer software that provides the infrastructure over which programs can operate, i.e. it manages and controls computer hardware so that application software can perform. Compilers Interpreter Assembler Editor

Languages High-level language: A high-level programming language is a programming language with strong abstraction from the details of the computer. close to user example: C++, java Middle level language : C Low-level language: a low-level programming language is a language that provides little or no abstraction from a computer's instruction set architecture. The word "low" refers to the small or nonexistent amount of abstraction between the language and machine language. close to hardware Assembly language

Assembly Language: fib: mov edx, [esp+8] cmp edx, 0 mov eax, 0 ret cmp edx, 2 mov eax, 1 ret push ebx mov ebx, 1 mov ecx, 1 lea eax, [ebx+ecx] cmp edx, 3 mov ebx, ecx mov ecx, eax dec edx pop ebx ret

Compiler A compiler is a computer program (or set of programs) that transforms source code written in a computer language (the source language) into another computer language (the target language, often having a binary form known as object code). Eg. Gcc, g++ etc. Editor: A text editor is a type of program used for editing text files. Eg. Vi,emacs, notepad, wordpad etc. Operating System: An operating system (commonly abbreviated as either OS or O/S) is an interface between hardware and user. An OS is responsible for the management and coordination of activities and the sharing of the resources of the computer. The operating system acts as a host for computing applications run on the machine. Eg. Linux, windows Assemblers: It converts assembly language in specific machine code

Interpreter An interpreter may be a program that either 1. executes the source code directly: XMLmosaicInterpreter 2. translates source code into some efficient intermediate representation (code) and immediately executes this : perl,Matlab 3.explicitly executes stored precompiled code made by a compiler which is part of the interpreter system : Java

hello.c :Program #include int main(){ printf(“Hello world”); return 0; } $ gcc –o hello hello.c $./hello

name :Shell program #! /bin/sh echo Enter your name read $name echo your name is $name $ chmod 777 name $./name