What is Linux?
Linux is strongly secured and a freely available, independent UNIX-like operating system for x86 machines. It’s an implementation of the POSIX specification with which all true versions of UNIX comply. The Linux kernel uses no code from AT&T or the other proprietary source, and far from the software available for Linux is developed by the Free Software Foundation’s GNU project.
It supports a good range of software, including X Windows, Emacs, TCP/IP networking (including SLIP/PPP/ISDN), and the works. Many of us have executed benchmarks on 80486 Linux systems and located them comparable mid-range workstations from Sun and Digital.
Linux (often pronounced with a brief “I” and with the primary syllable stressed — LIH-nucks) is out there over the web from many FTP sites, and from various vendors on floppies or on CD-ROM.
The Linux kernel is roofed by the GNU Public License (GPL), and is typically bundled with various binaries that comprise a working UNIX OS. These software bundles are called “distributions” and are available in many sizes and arrangements.
Linux is getting used today by many thousands of individuals everywhere on the planet. it’s used for software development, networking (intra-office and Internet), and as an end-user platform. Linux has become an economical alternative to expensive UNIX systems.
How is Linux Different?
One thing differentiating Linux from many other operating systems is that the price—it’s free. That is, it is often copied and redistributed without having to pay a fee or royalty to anyone. However, there’s more to the difficulty of Linux being free than price. Being licensed under the Free Software Foundation’s General Public License means the ASCII text file for Linux will still be available to anyone. The last five years of Linux development have shown the importance of this freedom; it’s resulted in a tremendous level of involvement for thousands—possibly many thousands—of people around the world.
This freedom has made it possible for hardware vendors to develop drivers for his or her particular devices without having to get an upscale ASCII text file license or sign restrictive non-disclosure agreements. it’s made it possible for people needing a real-time OS to slip a little real-time kernel under the Linux kernel. And it’s made it possible for computing students around the world to ascertain the insides of a true, commercial-quality OS.
What Is a Linux Distribution?
While Linux itself is freely available on the web, various vendors have built what are called distributions, which may be thought of as packaged versions of Linux. They include the Linux kernel, networking support, many utility programs, development software, a graphical interface and lots of graphics utilities, and far more. additionally, these distributions include some kind of installation software and should optionally include support.
Some distribution vendors make their complete distribution, including installation software, available free of charge on the web. Others elect to form their installation software proprietary and sell the package with support for a nominal fee—generally under $100. (See the review articles on a number of the favored distributions elsewhere during this buyer’s guide.)
This doesn’t mean there’s nothing left to shop for or wish for, but it does mean if, for instance, you’re a software developer, there’s unlikely anything you would like to shop for so as to show Linux into a fairly effective development platform.
One of the more common things people want to try to do is hooking up with the web. Everything you would like to attach to the web is out there for Linux for free of charge. In fact, there’s even software available free of charge which will turn Linux into a primary class web server.
How Does Linux Compare to Other Operating Systems?
Linux is predicated on the POSIX OS standard which was derived from Unix back when Unix was a product of Unix Software Laboratories. Today, Unix may be a brand available to OS vendors when their software passes a series of tests and that they pay a license fee. One Linux vendor, Caldera, is within the process of securing a Unix brand for his or her Linux product.
Unix is compatible with Linux at the supervisor call instruction level, meaning most programs written for either Unix or Linux are often recompiled to run on the opposite system with a minimum of labor. While what’s thought of as traditional Unix runs on more sorts of hardware than Linux, it pays the worth of over 25 years of luggage to form this possible. That generally means Linux will run faster than Unix on equivalent hardware. And Unix has the disadvantage that it’s not free.
MS-DOS is, in some ways, like Linux. That is, it’s a hierarchical filing system. But it only runs on x86-based processors, doesn’t support multiple users or multitasking, and it’s not free. It also has poor interoperability with other operating systems and doesn’t include networking software, development programs, nor many of the utility programs included with Linux.
Microsoft Windows offers a number of the graphics capabilities of Linux and includes some networking capabilities, but it suffers all the opposite disadvantages of MS-DOS.
Windows NT is out there for the Digital Alpha, also as x86 processors, but it suffers many of the disadvantages of Windows. it’s much less time within the field (meaning less time to figure out bugs), and it’s a rather large tag attached thereto.
Apple’s OS for the Macintosh runs only on the Mac. It also suffers from a scarcity of development tools and less-than-smooth interoperability with other systems. (Note: Apple has made Linux available for NuBus-based PowerMacs and is predicted to try to an equivalent for PCI bus-based Macs also .)
Whence Linux?
Where did Linux come from? First, and possibly most vital, Linux has its roots on the web. it had been developed by a really diverse group of individuals. This diversity includes knowledge and knowledge, but it also includes geography and spans virtually all of the surface. so as for this group to figure together they needed a fast and efficient thanks to communicating. the web was that tool and as Linux was the system of choice for these people it meant that the required tools to use the web appeared early in Linux. Those tools still evolve and to be honed as Linux development continues.
While the Linux kernel was an independent development effort, many of the applications are culled from the simplest available software. for instance, the C compiler is gcc from the Free Software Foundation’s GNU project. This compiler is usually employed by people using Hewlett-Packard’s HP/UX and Sun Microsystem’s Solaris operating systems.
What Is Included with Linux?
When you get Linux, you get “everything”. That is, everything you’d expect to be included with an OS and more. Each Linux distribution includes many packages offering a full and rich set of utilities, connectivity tools, and a development environment.
Here may be a list to offer you the overall idea:
development software including compilers, assemblers, and debuggers
text editors and text formatting programs
Usenet newsreaders and e-mail agents
World Wide Web development tools, web servers, and browsers
graphics creation and manipulation tools
When told Linux has most everything you would like, people tend to undertake to return up with something obscure or something they do not actually need just to check the bounds . for instance, you would possibly say you needed an Ada compiler for Linux. Well, the solution is yes, there’s an Ada compiler included with Linux.
Let’s check out an example of where Linux might be used and what’s needed to form it fit. the instance I’m thinking of maybe a small Internet service provider. (A small ISP to simplify the example—not because Linux isn’t capable of larger things.) The ISP employed by Specialized Systems Consultants, publishers of Linux Journal, has 14 Linux systems and supports many users simultaneously.
To offer this type of service you need:
Internet connectivity
multi-port, dial-up service
PPP and possibly SLIP connectivity
Usenet news
Mail routing
Web server
On-line backups
Most of those capabilities are inherent in Linux. The others accompany the hardware needed to support the potential.
For example, multi-port dial-up service is supported with serial communications products from Comtrol, Cyclades, Digi, Equinox, Gtek, Maxpeed, et al. Or, if you would like to undertake an external option, terminal servers work fine with Linux. Our ISP uses the Cyclades option and another local ISP uses Livingston PortMasters connected to the Linux hosts over Ethernet.
PPP and SLIP are integral parts of Linux. Their support and therefore the number of channels supported are configuration options once you build the Linux kernel. Besides regular Unix login/password security, support for PAP and CHAP are available.
Usenet news and Internet mail also are included. The software to support news includes the quality systems available on Unix platforms. INN seems to be the foremost popular. Mail is handled by Sendmail for many systems. While not as capable, small is additionally available and should be a far better fit low-end configurations.
Various web servers are included with Linux. At SSC we chose to use Apache because it’s reliable and efficient. the very fact that we handle about 100,000 hits per day on a 486 system with 16MB of RAM tends to support our choice. For those needing a secure web server, they’re not free but are available.
Finally, backups. so as to be a respected ISP you would like to supply continuous service and you cannot lose your customer’s data. After all, that’s why they pay you. Linux includes the quality Unix utilities to try to backups (tar, cpio, and backup/restore). There also are commercial products offering additional capabilities.
This doesn’t mean Linux comes with every application you would like to run your office or your entire business. However, while it’s going to not be included, it’s going to be available. for instance, databases, word processors, spreadsheets, and complicated graphics programs are available for Linux. you’ll see names like Applixware, Corel, and Empress within the Linux camp once you search for these kinds of applications.
Who Uses Linux?
A recent survey conducted by iX, a Unix and networking magazine based in Germany, showed some startling results. Linux is employed at work by 45% of the readers. Solaris 1 and a couple of taken together come second with 36%, followed by HP-UX with 27%. Of companies with fewer than 50 employees, 56% use Linux; it’s employed by 38% of firms with quite 1,000 employees. additionally, 60% of the readers use Linux on their computer reception. It is very old news and statistics.
Other places Linux has significant penetration is in web servers and because of the OS of choice in universities. Also, many individuals who’ve realized they have to find out about Unix for career advancement have decided to use Linux on their computer as a training tool.
Linux is additionally becoming popular in embedded and turnkey applications, including Internet firewalls, routers, and Point of Sale (POS) systems. This buyer’s guide was imaging employing a raster image processor (RIP) that supported a Linux system.
Linux History:
Linux was originally created by Linus Torvalds at the University of Helsinki in Finland. It’s been developed with the assistance of the many programmers across the web.
Linus originally started hacking the kernel as a pet project, inspired by his interest in Minix, a little UNIX developed by Andy Tanenbaum. He began to make, in his own words, “a better Minix than Minix”. And after a while of performing on this project by himself, he made this posting to comp.os.minix:
On October 5th, 1991, Linus announced the primary “official” version of Linux, version 0.02. Since then, many programmers have skilled his call, and have helped to form Linux the fully-featured OS it’s today.
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