UNIT - I. Syllabus Introduction to Open Source Operating Systems and Programming Languages, Introduction to Bharat Operating System (BOSS) GNU/Linux users

UNIT - I

Syllabus

Introduction to Open Source Operating Systems and Programming Languages, Introduction to Bharat Operating System (BOSS) GNU/Linux users model GUI, System Folders, study Commands (Using command terminal) with switches : ls, Directory Commands, Change user, privileges, passwords, tty, who, config, make, rpm, yum, sudo, Shutdown

Eclipse Editor, Compiler, Linker, Libraries, GUI, Configuring Programming Environments: C, C++. Java, Python (Pydev), Output, Debug windows

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Syllabus ..

Introduction to types of Programming Languages – Machine-level, Assemblylevel and High-level Languages, Scripting Languages, Natural Languages; Their relative Advantages and Limitations. Characteristics of a Good Programming Language; Selecting a Language out of many available languages for coding an application; subprograms.

Short Introduction to LISP, Simulation Platforms: MATLAB and GNU Octave(Open Source), Importance of Documentation, Documentation Platform LATEX (Free ware/Open Source).

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What is Computer?

Prof. N. B. Pokale

Computer is an electronic device used to perform Arithmetic & logical operations depeneds on input given to it .

Computers only understand binary language i.e. 0s and 1s

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Generations of Computer

First Generation Second Generation Third Generation Fourth Generation Fifth Generation

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First Generation

H/W Technology Vacuum tubes

S/W Technology M/C and Assembly Lang.

Prof. N. B. Pokale

Vacuum Tube

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Second Generation

H/W Technology Transistors

S/W Technology High Level Lang.


Third Generation

H/W Technology ICs with SSI and MSI technology

S/W Technology Standardization of High Level Lang.


Fourth Generation

H/W Technology ICs with VLSI technology,

Microprocessors S/W Technology

GUI based OS( multitasking), UNIX OS, C Lang, N/W based Applications,C,C++,smalltalk


Fifth Generation

H/W Technology ICs with ULSI technology, Larger Capacity Main

Memory & HDD S/W Technology

WWW, Multimedia Applications, Internet Based applications


Terminologies

Prof. N. B. Pokale

PC

Hardware (hard to change)

Software(easy to change)

System software

E.g .Operating system

Application software E.g. Railway reservation

system

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Prof. N. B. Pokale

Figure 1-4: Software

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Prof. N. B. Pokale

Secondarystorage

Input devices Output devices

Controlunit

Arithmetic/logic unit

Register storage area

CPU

Main Memory

Structure of Computer

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Hardware Components Central processing unit (CPU)

A hardware component that performs computing functions utilizing the ALU, control unit, and registers.

Arithmetic/logic unit (ALU) Performs mathematical calculations and makes logical

comparisons Control unit

Coordinates flow of data in/out of ALU, registers, primary and secondary storage, and various output devices


Hardware Components

Registers High-speed storage areas used to temporarily hold small

units of program instructions and data immediately before, during, and after execution by the CPU

Primary storage Holds program instructions and data (main memory)


Prof. N. B. Pokale

Memorytypes

PrimaryRAM,ROM

SecondaryHDD,CD,PenDrive

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Devices for Secondary Storage

• HDD

• Compact Disk Read-Only Memory (CD-ROM)

• Digital Video Disks

• Memory cards

• Removable storage


Input Devices

Prof. N. B. Pokale

•Digital cameras•Scanning devices•Touch sensitive screens•Keyboard•Mouse

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Output Devices

Display monitors Liquid Crystal Displays (LCDs) Printers and plotters


Storage Capacity

Unit Symbol

kilobyte KB 210 = 1024

megabyte MB 220 =1024 KB

gigabyte GB 230 = 1024 MB

terabyte TB 240 = 1024 GB


Applications of computer

Business application Industrial applicationsHome applicationsEducation and TrainingScience applicationsArts and Entertainment


Distribution of Software

Software made available to intended users through two forms.

i. Closed Source/Licensed

ii. Open Source

iii.Pirated

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Closed Source Software

Closed source software is a proprietary software

It is distributed under a licensing agreement to users.

The users can not modify, copy, or redistribute the software


Open Source Software

Open-source software (OSS) is computer software that is available with source code.

the source code and certain other rights normally reserved for copyright holders are provided under an open-source license that permits users to study, change, improve and at times also to distribute the software.

Open source software is very often developed in a public, collaborative manner.

Examples- Linux, Apache, Firfox, OpenOffice


Introduction to Open Source Operating System BOSS BOSS is GNU/Linux distribution developed by C-

DAC It is derived from Debian for enhancing the use of

free/open source software throughout India. It has support for almost all Indian languages. It is available in all the official Indian languages

such as Marathi, Hindi, Gujarati, Punjabi, Sanskrit, Tamil etc.


Features of BOSS User friendly Graphical Installer Indian version of OpenOffice- Bharatheeoo 3D Desktop Auto detection of devices Hardware support for many electronic gadgets Auto mounting of all hard disk partitions Localization support for desktop Smart common input method Migration tool- Bulk document converter Internet tools- Pidgin, Firefox, X-chat, Ekiga Multimedia support Kennel- An application to send SMS


Screen Shots of BOSS


Desktop Components


BOSS APPLICATION MENU


BOSS ACCESSORIES MENU


BOSS PLACES MENU


BOSS SYSTEM PREFERENCES


BOSS TERMINAL WINDOW


Linux System Folders



Root(/) The starting point of your directory structure. This is where the Linux system begins. Every other file and directory on your system is under the

root directory. Usually the root directory contains only subdirectories, so

it's a bad idea to store single files directly under root. Boot (/boot)

As the name suggests, this is the place where Linux keeps information that it needs when booting up.

For example, this is where the Linux kernel is kept. If you list the contents of /boot, you'll see a file called vmlinuz - that's the kernel.


etc (/etc) The configuration files for the Linux system. Most of these

files are text files and can be edited by hand. Some interesting stuff in this directory:

/etc/inittabA text file that describes what processes are started at

system bootup and during normal operation /etc/fstab

This file contains descriptive information about the various file systems and their mount points, like floppies, cdroms, and so on.

/etc/passwdA file that contains various pieces of information for each

user account. This is where the users are defined.


/bin, /usr/bin These two directories contain a lot of programs (binaries,

hence the directory's name) for the system. The /bin directory contains the most important programs that

the system needs to operate, such as the shells, ls, grep, and other essential things.

/usr/bin in turn contains applications for the system's users. However, in some cases it really doesn't make much difference if you put the program in /bin or /usr/bin.

/sbin, /usr/sbin Most system administration programs are stored in these

directories. In many cases you must run these programs as the root user.


/usr This directory contains user applications and a variety of

other things for them, like their source codes, and pictures, docs, or config files they use. /usr is the largest directory on a Linux system, and some people like to have it on a separate partition. Some interesting stuff in /usr:

/usr/docDocumentation for the user apps, in many file formats.

/usr/shareConfig files and graphics for many user apps.

/usr/srcSource code files for the system's software, including the

Linux kernel.


/usr/includeHeader files for the C compiler. The header files define

structures and constants that are needed for building most standard programs.

A subdirectory under /usr/include contains headers for the C++ compiler

/usr/X11R6The X Window System and things for it. The subdirectories under /usr/X11R6 may contain some

X binaries themselves, as well as documentation, header files, config files, icons, sounds, and other things related to the graphical programs.

/usr/localThis is where you install apps and other files for use on

the local machine


/lib The shared libraries for programs that are dynamically

linked. The shared libraries are similar to DLL's on Winblows

/home This is where users keep their personal files. Every user has their own directory under /home, and usually

it's the only place where normal users are allowed to write files.

You can configure a Linux system so that normal users can't even list the contents of other users' home directories.

/root The superuser's (root's) home directory. Don't confuse this

with the root directory (/) of a Linux system.


/var This directory contains variable data that changes constantly

when the system is running. Some interesting subdirectories: /var/log

A directory that contains system log files. They're updated when the system runs, and checking

them out can give you valuable info about the health of your system.

If something in your system suddenly goes wrong, the log files may contain some info about the situation.

/var/mail Incoming and outgoing mail is stored in this directory.

/var/spoolThis directory holds files that are queued for some

process, like printing.


/tmp Programs can write their temporary files here.

/dev The devices that are available to a Linux system. Remember that in

Linux, devices are treated like files and you can read and write devices like they were files.

For example, /dev/fd0 is your first floppy drive, /dev/cdrom is your CD drive, /dev/hda is the first IDE hard drive, and so on.

All the devices that a Linux kernel can understand are located under /dev, and that's why it contains hundreds of entries.

/mnt This directory is used for mount points. The different physical storage

devices (like the hard disk drives, floppies, CD-ROM's) must be attached to some directory in the file system tree before they can be accessed. This attaching is called mounting, and the directory where the device is attached is called the mount point.

The /mnt directory contains mount points for different devices, like /mnt/floppy for the floppy drive, /mnt/cdrom for the CD-ROM, and so on. However, you're not forced to use the /mntdirectory for this purpose, you can use whatever directory you wish. Actually in some distros, like Debian and SuSE, the default is to use /floppy and /cdrom as mount points instead of directories under /mnt.


/proc This is a special directory. Well, actually /proc is just a

virtual directory, because it doesn't exist at all! It contains some info about the kernel itself. There's a bunch of numbered entries that correspond to all processes running on the system, and there are also named entries that permit access to the current configuration of the system. Many of these entries can be viewed.

/lost+found Here Linux keeps the files that it restores after a system

crash or when a partition hasn't been unmounted before a system shutdown. This way you can recover files that would otherwise have been lost.

Linux Commands The Linux command line

As you probably know, there are two kinds of user interfaces out there: graphical user interfaces (GUI's) and command line interfaces (CLI's)

You probably know that in a GUI you control things by pointing and clicking with your mouse, and in a CLI you type commands with your keyboard.

The shell program The shell is the program that interacts between you and the

operating system. When you type commands, it's the shell that reads the commands from your keyboard, processes them, and finally gives them to the operating system.


Linux Commands….

pwd (Finding out where you are) The directory where you're currently working in, is

called (surprise surprise) the working directory. To find out where the working directory is, you use

the pwd command that stands for print working directory ls

It is a linux shell command that lists directories and files in the current directory.

Example ls –a ls -B


Linux Commands…. Directory command

cd: Changes direcotory dir: Briefly list directory contents mv: Move or rename files or directories rmdir: Removes directory

User and Privilege Management who: print all user names currently logged in who am i: Print current user id and username chown: change file owner and group chmod: change access permissions chgrp: change group ownership.


Linux Commands….

Password command passwd: Modify user password

tty: It stands for terminal type. It prints the file name of the terminal connected to standard input.

make: It is used to compile programs rpm: It is a powerful package manager. It is used to build,

query, verify, update and erase individual software packages.

yum: Yellowdog Updater Modified. It is used to install and remove packages.


Linux Commands….

sudo: It executes a command as another user. Sudo allows a permitted user to execute a command as the super user.

Shutdown: this command brings the system down. Shutdown brings a system down in a secure way. All the logged in users are notified that the system is

going down, and login is blocked. It is possible to shut the system down immediately or after a specified delay.


Eclipse IDE Text Editor

A text editor is used for editing plain text or text files Compiler

It translates source code into target language. Linker

It is used to link different files to make executable file. IDE

An IDE normally consists ofi. A source code editorii. Build automation toolsiii.A debugger or an interpreter or both



Eclipse Workspace Launcher


Eclipse IDE for Java Program

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What is Programming Language?

A language that is acceptable to computer system is called as Computer Language or Programming Language

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Types of Programming Languages

Machine-Level Assembly-Level High-Level

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Machine-Level Language

Only Lang understood by computer Consist of 0’s and 1’s It has two part format

Opcode It tells computer what function to perform

Operand It tells where to find or store the data, or other

instructions

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Advantages & Disadvantages

Advantages Faster Execution

Disadvantages Machine dependent Difficult to program Error prone Difficult to modify

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Assembly Language

Designed in 1952 Alphanumeric mnemonics codes instead of numeric codes

for instructions Each line consists of 4 columns [Label]<Opcode><Operand>[;comment] Example

Label Opcode Operand Comment

BEGIN ADD A,B ;Add B to A

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Advantages & Disadvantages

Advantages Easy to understand & use Easy to correct and locate errors Easy to modify

Disadvantages Machine dependent Knowledge of h/w required

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Assembler

AssemblerInput Output

Assembly Lang Program

Machine Lang Program

Definition: Converts Assembly Lang program into it’s equivalent

machine Lang program

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High-Level Languages

Overcome limitations of Low level Languages( Machine & Assembly Language)

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Compiler

CompilerInput Output

High-Level Lang Program

Machine Lang Program

Translate high levele lang. instructions into m/c lang. instructions

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Interpreter

Input OutputHigh-Level Lang Program

m/c Lang Program

Interpreter( Translates & Executes statement-by-statement)

Fig. Role of Interpreter

Translates statement-by-statement instruction into machine Lang & immediately executes resulting Machine Lang instruction

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Linker

Source File 1 Source File 2 Source File 3

Compiler

Object File 1 Object File 2 Object File 3

Compiler Compiler

Linker Program Library

Executable File

Fig. Role of Linker

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Loader

Loader is component of compiler Locates given program in offline storage Loads into main memory for execution

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Advantages of High level Lang.

Machine Independent Easy to Learn and Use Less Errors

Disadvantages Lower Efficiency

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FORTRAN

FORmula TRANslation. Designed for scientific and mathematical applications by

scientists and engineers. Algebra based lang General purpose and procedural language Oldest HLL BY JOHN BACKUS

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COBOL

COmmon Business Oriented Language. Best File handling capability Typically used for business applications. GRACE HOPPER

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BASIC

Beginner’s All-purpose Symbolic Instruction Code. Today, it is not used to develop the programs but used to

teach fundamentals of programming Interpreted language

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Pascal

● Named after French philosopher and mathematician Blaise Pascal.

● Start with keyword begin● Teaching Lang.● Platform independent● Used for scientific computational appl.

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C

Developed at Bell Laboratories in the 1972 by Dennis Ritchie.

Provides efficiency of assembly language while having third generation language features.

Often used for system programs. UNIX is written in C. Easy to learn and use Rich set of in built functions

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C++

Developed by Bjarne Stroupstrup in 1983 It is C language with additional features. Object oriented language

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JAVA

Developed by Sun Microsystem in 1991 An object-oriented language Platform independent Jvm is m/c dependent

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LISP

● LISt Processing Language● Language based on lambda calculus. (Mathematical

notation for expressing functions.)● Permit the use of recursion● Used in AI research

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MATLAB MATrix LABoratory Possesses tools for building custom GUI Includes mathematical functions

Linear algebra, Fourier analysis, numerical integration USE

Image & signal processing

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Scripting Lang

A scripting language is a form of programming language that is usually interpreted rather than compiled.

Used for web development Examples: Javascript ,vbscript,html etc

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Characteristics of Good PL Portability Reliability Performance Reusability

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Selecting Language for Coding

Selecting Lang out of many available Languages for coding an Application depending on following factors

Nature of Application Familiarity with Lang Ease of Learning Lang Execution Efficiency

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Documents

UNIT - I. Syllabus Introduction to Open Source Operating Systems and Programming Languages, Introduction to Bharat Operating System (BOSS) GNU/Linux users