Unix Client Server Technology

Understanding the Role of Unix

When discussing client-server technology it is important to understand UNIX, one of the first, primary building blocks for network possibilities that continues its influence today. UNIX is an operating system designed for multi-tasking by multiple users. This description alone suggests the exponential increase in work productivity by networking through UNIX. Operating systems (OSs) are computers’ central program. Every computer has one.

At their most general, operating systems help perform basic computational functions, such as recognizing keyboard input and sending output to the display screen. Operating systems manage external data, like disk files and directories, incorporating it so that it can be manipulated. Operating systems also manage peripheral devices, like keyboards, printers and disk drives. Larger operating systems have more responsibilities. They handle security and make sure that different users running programs simultaneously don’t interfere with each other. They also provide security to control access through authorization.

The primary way users interaction with operating systems is through commands. The command processor or command line interpreter executes these commands. The most popular and contemporary way of interacting with the operating system is through a graphical user interface (GUI). This allows the user to point and click on objects displayed on the monitor screen to input commands.

There are several types of operating systems: multi-user; multi-processing; multi-tasking; multi-threading; and real-time. A multi-user OS allows more than two, sometimes thousands, of users to run programs simultaneously. Multi-processing OSs support the running of a single program on multiple CPUs or central processing units (the brains of the computer). Multi-tasking OSs allow for more than one program to run simultaneously without interfering with each other. Multi-threading allows parts of a single program to run simultaneously. Real-time OSs allow for immediate response to input. UNIX, however, is not one of these.

The other major component of an operating system is the software platform, which is written on top of the operating system. The software platform allows application programs to run. Therefore, the operating system you choose will determine which applications your computer can run.

This article will focus on the UNIX operating systems, its components and functions, and its impact and contributions to client-server technology.

General Overview and Structure

UNIX is a multi-user, multi-tasking operating system originally designed to be used primarily by programmers. It is the leading OS for workstations (less popular with personal computers) and servers because of its flexibility and portability. Flexibility allows UNIX to adapt easily to new demands and correct any errors it detects. UNIX is one of the first OSs to be written in the high-level C programming language. This increased portability, since any machine with a C compiler could use UNIX. Compilers are programs that translate source code into object code, making UNIX command instructions intelligible across multiple operating systems.

Most high-level programming languages have compilers developed for them. C language has several compilers. This portability made it popular with academic and government institutions during its early implementation. The combination of UNIX and client-server technology has been central to the evolution of network, rather than individual, computing and the development of the Internet.

UNIX contains several identifying characteristics. For example, UNIX stores data in plain, unformatted, human-readable text such as ASCII (American Standard Code for Information Interchange), which is based on the English alphabet. It contains a hierarchical file system, which organizes files in directories in an upside-down tree formation with the ‘root’ or primary directory at the top. Files symbolize the leaves and the connections relating them are the branches. UNIX environments treat inter-process communication (IPC) devices as files.

Finally, UNIX enables multiple programs to be strung together using a command line interpreter or UNIX shell. These are programs that allow text entered by users to be processed and executed in the context of a specific operating system or programming language. Command line interpreters are organized through pipes, which are temporary software connections between two commands or programs. They pass the output of one command as the input for the next command.

UNIX structure is often described as a series of concentric circles, with hardware at the center, the kernel around that, utilities interact with and surround the kernel, and shells communicate with the utilities.

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