Myth 1. Any application software can be easily categorized as “fat” or “thin.”
A “Fat” Client: most of the application resides on, and runs on, the user workstation.

A “Thin” Client: most of the application resides on, and runs on, one or more server computers.

Real world Client/Server software has a range of architectures. Some designs may strike an even balance between what runs on the client and what runs on the server. Some may have characteristics associated with “fat” clients and some with “thin” clients. Netsmart’s Vital Records product is an example of an application that is hard to categorize as either “Fat” or “Thin”. It is even possible for a clearly “fat client” to run as thin using technologies such as Citrix or Microsoft Terminal Server.

Myth 2. “Thin Client” always means “Web browser.”
There were thin clients before the Web browser was invented. Thinness has to do with where processing happens, not the specific technology that implements it.

Myth 3. All Web Applications are “thin.”
While this is often the case, it is also possible to have varying degrees of “fatness” in a Web application. In typical Web Applications, programming code (by way of Java Script or VB Script) is downloaded with the Web page and executed on the client. In other instances, very large and “fat” applications can be encapsulated in an ActiveX control or a Java Applet and run on a Web page with characteristics very much like the classic “fat client”. And anyhow, a Web browser by itself is going to be fatter than most “fat client” software.

Myth 4. Fat clients have local databases; thin ones don’t.
It is correct that thin clients rarely have local databases. However, fat clients sometimes have local databases, but often do not. A fat client could operate with a local database and download data to a host in batches, but it could just as easily be directly connected to a remote database and update in real-time. A thin client, by definition, is limited in the amount of processing it can do on the client computer; fat clients have no such limitations. Netsmart’s VR product is an example of software that supports both local and remote database modes.

Myth 5. Fat clients are harder to deploy than thin clients.
This can be true, but not necessarily so. Many Web Browser applications, for example, require the installation of plug-ins, they may require complex downloading of security certificates and there are large potential problems brought on by the fact that not everyone uses the same Web browser or the same version of the browser. The browser version issue becomes more acute when the browser is asked to do more of the application’s processing through scripts, plug-ins, applets and active server pages. On the other hand, software that might be seen as “fat” can be installed and updated through Web interfaces. Many software applications, including Microsoft Windows, are now automatically updated across the Internet—and there is nothing “thin” about Windows.

Myth 6. Thin clients can use the Internet, but Fat clients can’t.
This is simply wrong. Both clients can be written with or without Internet capability.

Myth 7. Thin clients are easier to use.
Since thin clients do less processing on the user’s workstation, they typically are less interactive and therefore have less efficient user interfaces and are harder to use than a well-designed fat client.

Myth 8. Thin clients are more reliable than fat clients.
Anyone who has done much shopping online knows this isn’t true.

Myth 9. Thin clients run faster than fat clients.
This depends on how the application is built. On any modern workstation, there is a tremendous amount of processing power that is rarely used (i.e. wasted). Thin clients typically waste it more than fat ones. On the other hand, overworked servers are common and thin clients make this worse by offloading their processing to the server computer. The thin client overload of servers can be reduced by using more than one server in a “three-tier” model, where there are separate application and database servers. Three-tier applications are complex to deploy and administer.

Myth 10. Thin clients are the wave of the future.
It’s pretty hard to see the future. The real question is not “fat” versus “thin”, but what works for you today.