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Thin client or terminal is a diskless workstation connected to the server running the applications. At this, the terminal itself serves only for the information input and the display of the software interface. The terminal operation is of little difference from the regular computer operation. The major difference is the restricted local data storage, which is totally impossible with the thin client due to the unavailability of storage devices.

The administration and the users’ rights management processes are significantly simplified for the system administrator when using the terminals. Possibility of the centralized management of workstations is an undeniable asset when having a big number of workstations installed. Corporate informational system security also tells in favour of terminals. Relatively low price of terminals is another advantage. On the other hand, the economic advantage of the thin client purchases instead of computers can be reduced to nothing by the necessity of the powerful server installation. It becomes especially apparent when a big number of applications is used, each client linked up to the server requiring significant informational resources in place. Thin client is of no use without the server connection installed.

Thus, use of thin clients will be the most expedient in the organizations with a quite big number of employees performing homotypic work as well as in the organizations paying special attention to the corporate data security. These can be telephone service centers, banks, services, libraries etc. Thin clients are also appropriate for organization of regular office work, though depending on the used applications. If a major part of employees work with office software, the server traffic will not be that heavy. Though, when the graphical packages, video editing systems and CAD are used, the standalone workstations would still be the best option. The terminal work scheme will enable to optimize financial expenditure and build up a powerful, flexible and reliable information system enabling to use any applications, with the minimum support and maintenance expenses.

History of the Thin Client Generation

Thin Client is far from being a new invention. In the mainframes and electronic computers’ epoch when computers were of big size, the terminals were used for interaction of users with computers. The terminal itself served solely for information input and output. Computers which performed operations occuped quite a spacious hall and required special care. It was just impossible to install them in the work stations, thus making the terminal one of few methods of interactive communication with electronic computers. The situation changed when small computers appeared, followed then by personal computers. The terminals became unnecessary. They surely continued to operate in major service centers; though, most modern users never came across anything of that sort.

Though, let’s get back from the recent past. So, what does the state-of-the-art thin client represent? The start button is on the front terminal panel. The back panel is much similar to the panel with connectors as a regular computer has, as follows: two USB connectors and PS/2 for a mouse and a keyboard are located on it, one series port and one parallel port, a connector for switching to the local network, VGA-outlet as well as microphone port and the earphones outlet.

However, together with the local networks spread the idea of using the terminals instead of the full-configured computers gained a second wind. The idea of replacing the expensive PCs by simple clients capable of only being connected to the network and displaying images on the screen appeared to be quite attractive for many companies. The idea of graphical terminal serves as a basis for the X Window system used in all Unix-like systems; also, in most web applications some features of the same concept can be observed.

Ten years ago a concept of network computers proposed by Sun Microsystems Company caused big sensation. It was presumed that network computers will get connected to the network and perform applications in Java, as loaded from the server. However, the network computer idea did not bring any results. The commercial solutions development was suspended and reduction of prices for the regular PCs lead to the situation that “cheap” network computers turned out to be almost more expensive than the full office computers. Despite the Sun idea failure the concept of the disk-free terminal survived. Most of the state-of-the-art thin clients are based on it, though Java is not used in them.

Another version of the thin client is a regular personal computer which capacities are insufficient for interaction with up-to-date applications. If you install relevant software in such a PC it can be turned into the terminal for interacting with server performing all applications. A similar system was much spread in the schools where obsolete computers based on 386SX processors were used for working with Windows-applications launched in the server. Only non-complete version of Windows 3.11 was installed in 20-megabyte hard disks of work stations, which granted access to the server applications. However, experts do not recommend using old PCs as terminals due to their low reliability, difficulties of technical support and the lower data storage security level.

The system card of microITX format is hidden inside; microITX format is frequently applied in laptop computers. Chip VIA C3 with 533 or 733 MHz frequency rate is used as a central processor. Main memory capacity equals to 128 MB. In-built memory for the user’s information storage is not installed in the terminal, though thin client has a capacity of working with USB-drives (though, their usage can be forbidden by the administrator if necessary). Such external devices as printer, modem, smart-card scanner and others can be connected to the thin client.

Thin client advantages

WARRANTY	Increased reliability – Thin Client is a device, with its movable parts having actually no chances to fall out. Lengthy service life – it is 5-10 years, as a rule, unlike PCs that need upgrade (or replacement that is more frequent) every 2-3 years.
ECONOMY	Cheap and simple upgrade – the devices installed in the client stations do not at all require any upgrade. Upgrade of all work stations of the company is reduced to the upgrade of one or several servers that is much cheaper and is performed incomparably faster than the upgrade (and moreover, replacement) of hundreds of PCs. Operators’ labour productivity improvement – convergence of all service operation into the server significantly improves operators’ labour productivity. Equipment operation cost reduction – thin client’s operation is much cheaper, with not much difference from other equipment cost. Work station support technology streamline – Through application of relevant service resources the system administrator can support lots of devices simultaneously. Centralization of the desktop device administration – installation of the new and upgrade of the existing software is performed in the server; no need to perform it in each networked PC. Terminal systems enable the administrator to switch to the client session of the user and provide remote assistance and resolve emerging problems. Taking into account that the work stations can be located either in another end of the building or even in a different city, it enables to save a great deal of time and funds by avoiding expensive business trips devoted to the site visits by experts. Savings thanks to software licenses availability – Many packages require licences according to the number of simultaneous users. For example, if 30 employees out of 100 work stations use Lingvo Dictionary or Microsoft Power Point from time to time, though no more than 5 out of them load each of these applications, then it is possible to get only 5-7 licenses and distribute them between the employees based on the usage time, instead of getting 30 PC licenses, which would be necessary for the traditionally built OS.
MOBILITY	Users’ mobility - a user unattached to a specific work station can move within the framework of the local network at his/her will. Insensitivity towards the network transmission capacity – minimum information is transmitted between the client work station and the server (pressing the buttons, moving the mouse from the client, and a server command as to the screen refresh). Up to 20 KB/sec is enough for each client; the transmission capacity of one 100-megabit network segment is enough for work support of up to 100 users. Simple and fast installaton – adding new work stations is carried out by simply installing new terminals and their fast configuration on the server. Neither operation system installation or adjustment, nor applications installation or their configuration is required in the new work station. New work station creation process does not exceed 10 minutes – that is tens times less than for the regular PC.
SECURITY	Possibility of the user’s actions control – owing to the unavailability of drives in the work place a user cannot modify his software configuration by installing his/her own software. Controlled environment – users can launch only those applications that are installed in the server and which launch is allowed by the administrator. It makes easy to bar games launch in the work place as well as Internet abuse. Improved security level – when the terminal scheme is applied the server that stores all data can be placed anywhere – in a neibour building, in a different city or even a different continent. No privacy data will be saved in the work stations of the users; unavailability of removable drives will not allow copying important data to the external media. Thus, neither fiscal institutions nor rivals are able to get access to the privacy information. Even the client terminal theft does not bring troubles for the integrated circuit of the enterprise and сan not cause any serious damage to the business.