UNIX: Introduction to Beginners

What is UNIX? 

UNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking system for servers, desktops and laptops.

UNIX systems also have a graphical user interface (GUI) similar to Microsoft Windows which provides an easy to use environment. However, knowledge of UNIX is required for operations which aren't covered by a graphical program, or for when there is no windows interface available, for example, in a telnet session.

Types of UNIX :-

There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X.

Here in the School, we use Solaris on our servers and workstations, and Fedora Linux on the servers and desktop PCs.

The UNIX operating system:-

The UNIX operating system is made up of three parts; the kernel, the shell and the programs. 

The kernel:

The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the filestore and communications in response to system calls.
As an illustration of the way that the shell and the kernel work together, suppose a user types rm myfile (which has the effect of removing the file myfile). The shell searches the filestore for the file containing the program rm, and then requests the kernel, through system calls, to execute the program rm on myfile. When the process rm myfile has finished running, the shell then returns the UNIX prompt % to the user, indicating that it is waiting for further commands.

10 Open Source Tools For Building Scalable Web Applications!

When you're designing a web application, scalability and performance are very important. Every developer must take these two steps into consideration before building their application. To do this effectively, you need the best tools. Here are 10 of the most popular ones.

1. Apache HTTP Server: Extensible, fast and highly scalable. These are the qualities of the Apache HTTP server that make it immensely popular. Of course, there are other features too.

2. Tomcat: This open source software holds configuration and management tool. While the Apache Tomcat tool is an implementation of Java, it can also be configured using configuration files from XML. You can use it to implement JSP along with Java servlet specifications.

3. Modsecurity: This is a web application firewall that can be embedded into the web server infrastructure. It is also amongst the top available open source WAF solutions.

4. Memcached: This is an open source distributed caching system that is generic in nature. It has a simple design and delivers very good performance.

5. Varnish: This is a web application accelerator or HTTP reverse proxy. It is a very high speed software that can speed up the process delivery immensely.