Introduction of UNIX

Posted by Bhavesh Joshi On Wednesday, February 16, 2011 0 comments


Pronounced yoo-niks, a popular multi-user, multi-tasking operating system developed in the 1960s at the bell laboratory. Created by just a handful of programmers, UNIX was designed to be a small, flexible system used exclusively by programmers. UNIX is a highly programmable language (an operating system) and still regarded as one of the most powerful, versatile, and flexible operating system (OS) in the computer world. UNIX Systems have Graphical User Interface (GUI) facility like Microsoft Windows which to easy to use. The most famous varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.

It was designed for a programmer not for a casual end-user. A programmer can easily operate UNIX operating system.

Multi-tasking Facility
Many computers do just only one thing at a time, as anyone who uses a PC or laptop can attest. But, on the other hand, UNIX lets a computer do several things at once, such as printing out one file while the user edits another file. This is a major feature for users, since users don’t have to wait for one application to end before starting another one.

Multi-user Facility
The computer can take the commands of a number of users, determined by the design of the computer to run programs, access files, and print documents at the same time. This is the best facility of UNIX.

It has fast speed with respect to others and it is mainly divided in three parts as follows -
1. The Kernel
2. The shell and
3. The programs

The Kernel
It controls the hardware and turns part of the system on and off at the programmer’s command. If you ask the computer to list all the files in a directory then, the kernel tells the computer to read all the files in that directory from the disk and display them on your screen.

The Shell
Shell is used to act as an interpreter between the user and the computer as its purpose is same like Kernel. There are several types of shell as most notably the command driven Bourne Shell, the C Shell (no pun intended), and menu-driven shells that make it easier for beginners to use.

The Programs
There are hundreds of programs available to UNIX users. Typically, they are grouped into categories for certain functions, such as word processing, business applications, or programming.

The main features of UNIX are—
• Multitasking capability
• Multiuser capability
• Portability
• UNIX programs
• Library of application software

Finally, UNIX is the best operating system, very admired as today it is using by billions of peoples…

Introduction of C Language

Posted by Bhavesh Joshi On 0 comments

Introduction of C LanguageC language is the first language of the PC system which was developed between 1969 and 1973 by Dennis Ritchie at Bell Telephone Laboratories. The primarily development of ‘C’ occurred in AT&T Bell Laboratories. In 1978 Brain Kernighan and Ritchie printed a definitive description of the language observed to as K & R version of C. Various C compilers and interpreters had been written for various operational systems. This created some minor incompatibilities among totally different implementations of the language. That's reason, the ANSI (American National Standard Institute) worked on a typical (standard) version of C language.
C has diverse data types for diverse types of data and can be broadly classified as:

1. Primary data types
2. Secondary data types

These above broadly classified data types are well illustrated at below Image…

C Data Types

C is an all purpose programming language. It is equally suitable for generating higher level applications and lower level applications. C language encourages the users to write their own library function so that they can extend the features of the language and C program can be executed on any type of computers. The program written in C language can be converted into machine language more efficiently. Computer games can be generated in C language which is accomplished through the usage of sound graphics. Both low and high level programming can be done in C language. C language is the address manipulation which can be done through the usage of pointers. C is simple, fast, and efficient, the first stage for a programmer. C is close to hardware.

Why we have a tendency to use C firstly?

In today’s world of computer languages, there are several high-level languages to decide on from, like Pascal, BASIC, and Java. However C stands excluding of these languages. This is often owing to its several fascinating qualities. It's a strong language whose wealthy set of constitutional functions and operators is wont to write any complicated logic program. The C language compiler combines the capabilities of an occasional (low) level language with the options of a high level language. so the language is appropriate for writing each system code still as business packages & different code. You'll several compilers offered within the market written in C.

The general way to write program in ‘C’ as-

void main ()
   printf (“Hello”);

Here, output will - Hello

Through this way, programs can be written in “C Language”. Programs are of several types in ‘C’ as switch case programs, array programs, pointer programs, functions programs etc. All have different uses on different places.

Finally, C is the primary common language of Computer System…