file extension SWP

Unix

Unix operating systems are widely used in both servers and workstations. The Unix environment and the client-server program model were essential elements in the development of the Internet and the reshaping of computing as centered in networks rather than in individual computers.

Both Unix and the C programming language were developed by AT&T and distributed to government and academic institutions, causing both to be ported to a wider variety of machine families than any other operating system. As a result, Unix became synonymous with "open systems".

Unix was designed to be portable, multi-tasking and multi-user in a time-sharing configuration. Unix systems are characterized by various concepts: the use of plain text for storing data; a hierarchical file system; treating devices and certain types of inter-process communication (IPC) as files; and the use of a large number of software tools, small programs that can be strung together through a command line interpreter using pipes, as opposed to using a single monolithic program that includes all of the same functionality. These concepts are known as the Unix philosophy.

Under Unix, the "operating system" consists of many of these utilities along with the master control program, the kernel. The kernel provides services to start and stop programs, handle the file system and other common "low level" tasks that most programs share, and, perhaps most importantly, schedules access to hardware to avoid conflicts if two programs try to access the same resource or device simultaneously. To mediate such access, the kernel was given special rights on the system, leading to the division between user-space and kernel-space.

The microkernel concept was introduced in an effort to reverse the trend towards larger kernels and return to a system in which most tasks were completed by smaller utilities. In an era when a "normal" computer consisted of a hard disk for storage and a data terminal for input and output (I/O), the Unix file model worked quite well as most I/O was "linear". However, modern systems include networking and other new devices. As graphical user interfaces developed, the file model proved inadequate to the task of handling asynchronous events such as those generated by a mouse, and in the 1980s non-blocking I/O and the set of inter-process communication mechanisms was augmented (sockets, shared memory, message queues, semaphores), and functionalities such as network protocols were moved out of the kernel.

Linux

Linux is an operating system that was initially created as a hobby by a young student, Linus Torvalds, at the University of Helsinki in Finland. Linus had an interest in Minix, a small UNIX system, and decided to develop a system that exceeded the Minix standards. He began his work in 1991 when he released version 0.02 and worked steadily until 1994 when version 1.0 of the Linux Kernel was released. The kernel, at the heart of all Linux systems, is developed and released under the GNU General Public License and its source code is freely available to everyone. It is this kernel that forms the base around which a Linux operating system is developed. There are now literally hundreds of companies and organizations and an equal number of individuals that have released their own versions of operating systems based on the Linux kernel. More information on the kernel can be found at our sister site, LinuxHQ and at the official Linux Kernel Archives. The current full-featured version is 2.6 (released December 2003) and development continues.

Apart from the fact that it's freely distributed, Linux's functionality, adaptability and robustness, has made it the main alternative for proprietary Unix and Microsoft operating systems. IBM, Hewlett-Packard and other giants of the computing world have embraced Linux and support its ongoing development. Well into its second decade of existence, Linux has been adopted worldwide primarily as a server platform. Its use as a home and office desktop operating system is also on the rise. The operating system can also be incorporated directly into microchips in a process called "embedding" and is increasingly being used this way in appliances and devices.

Throughout most of the 1990's, tech pundits, largely unaware of Linux's potential, dismissed it as a computer hobbyist project, unsuitable for the general public's computing needs. Through the efforts of developers of desktop management systems such as KDE and GNOME, office suite project OpenOffice.org and the Mozilla web browser project, to name only a few, there are now a wide range of applications that run on Linux and it can be used by anyone regardless of his/her knowledge of computers. Those curious to see the capabilities of Linux can download a live CD version called Knoppix . It comes with everything you might need to carry out day-to-day tasks on the computer and it needs no installation. It will run from a CD in a computer capable of booting from the CD drive. Those choosing to continue using Linux can find a variety of versions or "distributions" of Linux that are easy to install, configure and use. Information on these products is available in our distribution section and can be found by selecting the mainstream/general public category.

Introduction to Mac OS X

Ever wonder why people get so attached to their Mac? Think Mac OS X. At the core of every Mac, Mac OS X is what makes your digital life more simple, more productive, and just plain fun.

It’s easy.

Mac OS X is a celebration of simplicity and common sense. No complicated menus. No obscure commands. Most tasks can be accomplished with just a click or two. And if you ever need guidance, there’s a built-in help system to light the way. Oh, one more thing: Mac OS X is simply breathtaking — and easy to personalize with desktop pictures and screen savers.

It’s advanced.

Making amazing things simple takes seriously advanced technology. Mac OS X is built on a rock-solid UNIX foundation, delivers true 64-bit performance, and incorporates industry-leading animated graphics. The beauty is, you don’t have to know what one word of that means — just start up your Mac and enjoy it.

It’s amazing.

More than an operating system, Mac OS X is a collection of very cool applications. It comes with everything you need to surf the web, send beautifully designed email, video chat, and organize your personal information.

It’s secure.

In a world where PCs constantly do battle with viruses and malware, Mac OS X is a sea of tranquility. Just go about your business and Mac OS X minds the fortress. Your documents are safe even if you share your Mac with others, and you can keep your kids safe by using a rich set of parental controls.

It’s compatible.

It’s a big world out there, and Mac OS X fits in perfectly. It runs Microsoft Office. It has built-in drivers for cameras, printers, and external drives. It plugs right into a PC network. And in case there’s a PC application you can’t live without, Mac computers can even run Windows. Mac OS X is compatible with everything — most of all, you.

Microsoft Windows

Microsoft Windows is a family of operating systems by Microsoft. They can run on several types of platforms such as servers, embedded devices and, most typically, on personal computers. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing trend of graphical user interfaces (GUI) popularized by the Macintosh. Microsoft Windows eventually came to dominate the world's personal computer market.