Thin Clients vs. Fat Clients

There has been a lot of debate recently over which is the better networking device, a thin client (NC) or a fat client (PC). Heated arguments about the merits of one or the other rage on. Do we really need powerful PCs on every worker's desktop or can thin clients meet the challenge? Do these stripped down, bare-bones machines really save money?

Historical perspective

In the not too distant past, it was thought the decentralized, client/server model of computing, where each user has his own full-featured personal computer, had supplanted the older, centralized model where users had only dumb terminals and shared a larger mini-computer or mainframe. But the rising cost of owning and maintaining these networked PCs has left many businesses wondering if the old days weren't so bad after all. For more information on this topic, see The Hidden Costs of Client/Server.

What is meant by a fat client

In genreal what we refer to as a fat client is a fully configured desktop personal computer, with a floppy drive, a large hard disk, a CD-ROM drive, and an ample amount of both memory and processing power. These machines also have an operating system, Microsoft Windows, that has grown very large over the years, along with a full complement of equally bloated applications' software. All this adds up to a very heavy client. While users like the power and flexibility inherent in this type of client, management of these machines in a network has become a nightmare. The training costs involved in getting new users up and running are daunting and upgrading the operating system or application programs has become a monumental task.

What are some of the problems fat clients create?

In fat client networks, the server is mainly used for storage of data. Because the application programs are on the client, any needed changes are physically difficult to implement. Users can also tamper with basic settings or install software both of which can lead to problems that are not easy to solve. A great deal of productive time is lost when users try to figure out what went wrong and attempt to fix it themselves.

Being complex, PCs are more trouble prone and likely to need technical support. They are subject to viruses, software conflicts, corrupted files, and need to have both the operating system and applications updated regularly to keep in step with current technology. Having local storage also makes valuable company data less secure. A stolen computer means more than the loss of a piece of hardware.

What are thin clients?

Thin clients represent a diverse group of computing devices but there are three things they all have in common.

In general thin clients cost less than PCs. They usually lack both floppy and CD-ROM drives. Hard disks are optional and when present, are used only as a cache to help improve speed and efficiency. There is no local storage. All programs and user files are stored on a server.

Having all business logic and data on the server makes thin clients simpler machines that require much less in the way of maintainance. They are designed to be interchangeable and easily replaced. On the other hand, managing, maintaining, and replacing PCs over the long haul is very expensive.

Thin clients are stateless machines with no local storage. When a user logs in, his environment is brought to him from the server and displayed on his desktop. Unlike PCs, if the machine should break no data is lost and there is no need to install or configure anything on the replacement. They much simpler devices and are primarily designed to save administrative costs.

Thin client types

Not all thin clients are alike. There are two basic types, the thin client terminals and the newer Java-centric network computers. The latter machines are new devices designed to run software written in the Java programming language while the former machines which are more like true terminals in the techincal sense, are designed to run the more traditional Windows software.

The Java-centric thin clients

While they can access data and run Windows programs like any PC or thin client terminal, the basic idea behind these machines is a total departure from the standard PC platform and operating system. Sun's JavaStation and Oracle's Network Computer are two examples of this type of machine. The greatest advantage to having programs written in Java is they are independent of any operating system or CPU because everything below the Java virtual machine is abstracted. This allows system administrators a great deal of freedom because they are not dependent on one vendor for their underlying hardware. Programs written in Java can execute on any platform that has a Java run-time environment. There is one more thing to consider. Java programs are downloaded from a server but they run on the desktop, not on the server, making these NCs real computers not just terminals.

Thin client terminals

The other type of NC is more like the traditional terminal. They offer all the advantages of thin clients but are designed to run Windows and other popular software which makes them easier to integrate into existing systems. In contrast to the Java-centric NCs, programs do not execute on the desktop, but are run remotely over the network from a server, so technically they are terminals. But thin clients offer more possibilities than old dumb terminals which are just keyboards and screens wired-up to a central computer. Graphics are processed locally, providing a graphical user interface, and they give users access to the Internet, e-mail, and corporate intranets. Wyses' Winterm terminals and Citrix's WinFrame terminals are prime examples of this type of thin client.

For more information, follow these links to vendors offering various solutions for deploying thin clients in networks.

Boundless Technologies Insignia Solutions, Inc.
Acorn Computer Group plc Citrix Systems, Inc.
HDS Network Systems, Inc. Network Computing Devices, Inc.
Network Computer, Inc. Wyse Technology Inc.
The Santa Cruz Operation  

When to use thin clients

Thin clients are not a one-size-fits-all solution. For example, if your users are graphic artists, who need a variety of peripherals such as scanners, removable storage devices, and CD-ROMs, a thin client just won't work. Users who need lots of local processing power or need to install new software frequently are also not good candidates for these machines.

The key to achieving success is to match the computing device to the skills and needs of the worker. Data entry to a remote database for instance benefits from the thin client approach. Because they stateless, workers can easily share a thin client machine and still enjoy their own personal environment every time they log on.

In conclusion

NCs can help cut costs and simplify network management but they are not likely to replace every personal computer. There will still be some users who need a more powerful and flexible machine. It is important to remember there are many ways to set up a client/server network to get your work done. NCs do not change the basic client/server network model, they simply expand the options available. There are situations in which fully featured personal computers are the way to go and others where a less well endowed machine will suffice. It is a matter of what you need to do.

Selected References

Trendwatch Straight talk on "thin clients"
Downsizing desktops with thin-client rollout Neither Too Fat Nor Too Thin
Thin, Fat, or Dumb? Thin Clients, Thin Networks... Maybe
Fat Clients-Thin Clients NCs: Just Thin Wintel Clients?

On the lighter side

Fat Client, Thin Client

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