What is Linux?
Introduction to Linux.
Every time you start browsing, chatting, typing a letter or playing in your computer, you are using an operating system. An operating system is set of instructions that let hardware and software to work together. So, the operating system can be considered as the most fundamental set of programs that supports hardware and software interaction.
Linux is a free operating system, developed under open source policies. It runs in most hardware types (x86/x64, ppc, and others) and everybody is granted to re-distribute it.
Linux Torvalds started Linux based on Minix, a UNIX-type operating system. In opposition to make a non-distributable software, Linus released its code invention to others developers to make improvements to it. Moreover, Linux was borned “patent-absent” to make easier the code edition and the sharing capability.
UNIX, was developed by many companies, and there are many distribuitors, too. However, it can be distinguished two development branches:
- System V.
- BSD (Berkeley Software Distribution).
Development and distribution is more complex to Linux than to UNIX. Linux development is supported by programmers of everywhere in the world, they contribute by making and testing software, by making money donations and looking for software bugs and fixing them.
From the computational viewpoint, it can be said that Linux is clon of UNIX. Yes, it is! Don’t forget that Minix, a UNIX-type operating system is the “father” of Linux. So, as Linux is a UNIX clon, it is easy to know that it shares features of his father. These are some of these features:
- Multitasking.
- Multi-user.
- Programmable shells.
- Device independence.
- A very strong network capability.
In addition to these features, it is important to highlight that Linux is open source, easy to implement in heterogenous hardware and free price (in most cases).
But… if you thought: “What about my spreadsheet processing, my games, etc…? Where are them? You are not speaking about it.” You are correct! An operating system, as Linux, doesn’t have this software diversity by default, but,it was solved by the Free Software Foundation (FSF), a non-profit company that develop and join efforts among programmers to release open source software to Linux. They developed core programs used in Linux. Moreover, the FSF is the creator of the GPL, a type of license that let you share, modify and to study the software and redistribute it under the same conditions.
It seems to be a good moment to start talking about the Linux features:
- Multitask.
By this one name is known to the faculty that Linux has to execute, seemingly, of simultaneous form, many programs without hindering the execution of every application. This is multitasks preferable. The operating system allows him to work when it has his shift insured and without harming to other programs. Another system multitasks exists also. It is called: multitasks cooperative. This system multitasks is not own of Linux. It happens here that a program in execution is the one who decides or not it execution of another one.
In order to give him to a perspective of hardware to the preferred system multitasks, the one of Linux, I will say that a microprocessor only can make a thing simultaneously. In agreement microprocessors become of greater frequency, the instructions execute-are finished more quickly, but, the principle of ?a thing simultaneously? continues being he himself. It is valid for all the computers, without perjucio of age.
- Multiuser.
In surroundings of work of many users, to have access from a same computer to an application on the part of several individuals is a useful and necessary capacity. Several people can be connected to the same computer and simultaneously they can be using the same program. They can be working in different things using the same application. It is the the “multiuser” capability.
The work in a same project is not “multiuser” feature, it is part of. The last paragraph makes a good meaning of the multiuser feature.
- Devices are independent.
Any known computer device is a file, for Linux. It makes a great improvement to the system because such devices can be link or unlink to/from the system with just editing certain files used to manage the hardware. For example, consider to remove your second hard drive from the Linux box. It’s unnecessary to open your case and to unplug the hard drive… Linux solves it by unmounting this hard drive, in this way:
umount /mnt/disk2
in this particular case, this command unlinks the second slave hard drive from being used.
If you want to remove this disk entirely from your system, you must edit the file: /etc/fstab and to remove the corresponding line about your second hard drive. For example:
/dev/hdd /mnt/disk2 …………………………………….
then, save the file.
A printer is a file, a directory is a file, a single file is a file… everything is a file in Linux.
- Advanced memory handling.
Linux novices users get worried often when they check their memory usage… Almost all memory is used!!! However, this is not a problem. This a improvement!!! You must learn that unused memory is wasted memory. So, Linux tries to use most of the memory. It loads more quickly the programs and your system gets no slow because the Linux kernel manages great all the input and output tasks (refer to multitask feature described first).
- Strong network capabilities.
Linux is to network like a fish to the water. Why the strongest Internet servers are running on Linux? Linux is the best choice to network because it had been designed to manage all network tasks. All protocol implementations are built in to the kernel and new features can be loaded on the fly without to restart the server.
Others non-*nix systems needs to reboot in order to take a new internet protocol. It is common that such new implentation must be bought from a single or many providers. It increases the cost to the enterprise and makes a loss of time and money while rebooting the system.
As Linux has network capabilities built in, it is more difficult to have downtimes, it makes more secure the system and it is usually free cost.
- Free cost.
Most Linux distributions are free-cost and they can be downloaded from Internet. Commercial sales and support can be get from many Linux vendors, but, it is just a choice for you.
I prefer to download my distributions and to burn them. It is more funny, for me.
GNU/Linux distribution files are very big, so, if you are going to download a Linux distribution you need to have a very quick Internet plan or you’ll become very old or will receive a high cost phone or Internet invoice.
If you don’t have trouble with velocity, start downloading… you are going to get a free cost operating system specially designed to fit any user needings.
