Software architectures
Sep 1, 2008 12:00 PM, By Brad Gilmer
The style you choose affects the entire facility design.
Software architectures can have a big effect on facility design, especially for broadcasters. Anytime applications work with video, it is important to pay attention to how and when this demanding data is moved within the facility and how much processing power is required.
Types of architectures
Software designers have developed many architectures over the years. Different applications in a broadcast facility fall into four categories:
Figure 1. This simplified diagram illustrates the most common types of software architectures for broadcast facilities.
Click to enlarge
- Stand-alone applications run entirely on the system in front of the operator.
- Thick-client applications run on the system in front of the operator, but require access to a server or other outside connection, typically for access to data.
- Thin-client applications run primarily on a server, but have a small piece of software running on the system in front of the operator.
- Web client applications run on a server, either internal to your company or over the Internet, and are accessed via a Web browser.
Figure 1 shows each of these types of applications. Table 1 lists these four categories with a rough classification of the amount of network bandwidth consumed by the application, the relative security risk, the amount of CPU load, the amount of data access load, the amount of server CPU load and the server data access load. These architectures result in different requirements for your networks, the type of desktop computers you deploy and the types of servers required.
Stand-alone systems
In a stand-alone system, everything you need to run the application is contained on the system in front of the operator. Think about a desktop video editing application, for example. Assuming that the project you are editing is stored on the local hard disk, you can edit without a connection to any other resources. Given the lack of a network connection, no network bandwidth is required, and there is no network security risk.
However, because all of the application processing is done on the desktop, the CPU load is high. Also, all of the data is stored locally, so the local data access is high as well. An external server is not involved; therefore, the server CPU and data access loads are zero.
Thick-client systems
In a thick-client system, the client does all of the processing but it is connected to some other resource, typically a database, to access shared data. The amount of network bandwidth required by a thick client depends on the application. Most of the traffic is transactional, so the bandwidth requirements are usually low to moderate. Because the thick client requires a network connection, security is more of a concern. However, most thick-client applications connect to resources inside a corporation, so most of the security risk is mitigated by a corporate security structure.
All of the application's processing is performed by the client; therefore, the desktop CPU load is high, but the amount of data moving on the network is low to moderate. All of the data processing is done on the desktop client. As a result, the server CPU load is low, primarily consisting of user authentication and simple file transfer tasks. The server acts as the central repository for data, and most of these applications are multiuser, so the server data access load can be moderate to high depending on the number of users involved.
The thick-client application can run on a conventional desktop, and the server may not require a lot of processing horsepower. However, if the application is used simultaneously by a large number of users, the server data I/O demands may be high.
Thin-client systems
In thin-client systems, the software designer offloads processing from the desktop to the server. The goal is to allow the deployment of less expensive desktop systems, while concentrating processing power in a central server. Typical thin-client systems run a lightweight application on the desktop and do the heavy lifting at the corporate application servers. An example of a thin-client application is an airline reservation system.
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