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1. Introduction to Server-based computing

What is server-based computing?

Server-based computing (SBC) is a technology whereby applications are deployed, managed, supported and executed on the server and not on the client. Instead only the screen information is transmitted between the server and client. This architecture solves the many fundamental problems that occur when executing the applications on the client itself.
In SBC environments hardware & software upgrades, application deployment, technical support, and data storage & backup are simplified because only the servers need to be managed. Data and applications reside on a few servers rather then on hundreds or thousands of clients. PCs become terminals and can be replaced by simpler, less expensive and most importantly easier to manage devices called "thin clients."

The benefits of server-based computing

  1. Management - Administrators can deploy, manage and support applications much more easily because they are held on a central server (or central server farm) and are managed from a single point, simplifying application access and administration.
  2. Device independence - Users can access their desktop and indeed any enterprise application from any type of client device.
  3. Remote Access – Users can access their desktop and enterprise applications from anywhere on the network, or from home, or on the road.
  4. Performance – Server-based computing performs better than a web application or using a client server model. These types of applications require a lot of data to be sent back and forth between the server and the client. Because of the advanced compression ratios achieved by protocols such as ICA, NX and RDP, sending just the screen updates between the server and client is much faster.
    1. Security – Server-based computing keeps all the data on the secure servers without it being 'spread out' onto the less secure client computers. Furthermore the server is in the server room, which is far more secure than on the user’s desk.
  5. Less prone to viruses and security breaches – Servers are by definition better managed and because the server OS is more secure, it’s far more difficult for a computer to get infected by a virus.
  6. Eliminates patch management of clients – Clients are not running Windows, there is no need to patch the desktop computers on a regular basis.
  7. Server-based computing reduces Total Cost of Ownership [TCO] by as much as 50%.
  8. Scalability – New servers and clients can easily be added to the network.
  9. Increased availability – It’s easy to make the terminal servers fault tolerant and to perform load balancing. In addition, servers are inherently designed to be more reliable than your average desktop.

What are thin clients?

A thin client is a general term for a device that relies on a server to operate. It provides a display device, keyboard and mouse and basic processing power in order to interact with the server. It does not store any of the data locally – it’s very thin in features and functionality – hence the term 'thin client'.
A thin client often does not have local storage and requires little processing resources. Thin client hardware can be a converted old PC, a dedicated thin client device, or simply a new low cost PC with a thin client OS installed. The fact that little processing power is needed and that the hardware can be used for longer periods of time (on average 6 years instead of 3 years) means that the capital expenses for desktops is significantly reduced.
Most importantly, the overhead costs associated with administration, maintenance, support, security and installation are significantly lower than with a traditional PC.

How does it work?

2XThinClientServer01.jpg
Figure 1: Server-Based Computing
The server-based computing technology revolves around 3 main components:
  1. A multi-user operating system that allows multiple users to log on and work concurrently, using applications in separate, protected sessions on a single server. Examples of terminal servers are Microsoft Terminal Services 2000/2003, Citrix Metaframe and 2X TerminalServer for Linux.
  2. A thin client, which runs a minimal amount of software, but at least one program that connects to the terminal server. The thin client and the terminal server can be running completely different types of operating systems: For example Linux based thin clients are currently the most popular way to connect to a Windows terminal server! On the thin client there will be a program such as rdesktop (Linux) or Remote Desktop Connection (Windows) to connect to the terminal server.
  3. A protocol to allow the terminal server and thin client to communicate and send only the keystrokes, mouse clicks and screen updates across the network. Of course this will be suitably compressed. Popular protocols are RDP (Remote Desktop protocol), ICA and NX.

Server-based computing advantages in a nutshell

Server-based computing is currently considered as the most efficient, flexible and cost-effective solution for application delivery and administration. It boasts the following advantages: