Centralization and Decentralization

Centralization

In the early days of mainframe computers, nearly all computing and network power was centralized in a large data center. Users logged on to machines called dumb terminals to perform their tasks. They were so named because the terminal had no intelligence or sophistication to it. All the programming and functionality were contained in the mainframe; the dumb terminal just accepted user commands and rendered a display with the results. These dumb terminals were placed in offices and cubicles where users needed to work, whereas all the data was safely locked up inside the vault of a data center.

Even though mainframe computers are not used as much today, many resources are still centralized. For instance, strongly centralized web-based applications allow phones, tablets, and computers to behave like dumb terminals. The web browser on these devices does not perform the complex calculations or even store the data that are used within these apps. Instead, the computing and networking resources are hosted in a remote centralized data center, such as a corporate headquarters or a cloud data center. In some ways, cloud computing has allowed a strong centralization approach to make a comeback. You can perform the heavy processing in the cloud without concerns about the hardware of the user’s device.

Diagram. Centralized network.

While security is a great benefit of centralization, it is not the only reason to centralize resources. By placing the computing and networking power in a central location, the owners and operators of the applications can better control the performance and availability of the applications. To help explain that point, think about a web-based application that is also available as a locally installed application on your phone. QuickBooks and Office 365 are two good examples, but there are many others. Imagine that you have an older phone, one that has no trouble opening web pages, but other applications just do not run as fast as they used to. You may favor the website version of Office rather than the installed version because it performs better on your phone. Here is what is going on behind the scenes. When accessing Office via the web browser, you are using a centralized web server farm that is running the application for you and just sending back the changes to the display. The performance is also much more constant and reliable, assuming that you have a good internet connection, because the application owners and operators have centralized their resources and can add more resources to their servers during periods of high demand, ultimately keeping the application running well and giving you a positive experience.

Now imagine that instead of using the web-based version of the application, you are using the locally installed version of that application. The performance of the application is based on the processing power of your hardware rather than servers in the cloud. This may allow you to use the application while you are disconnected from the network, but the application owners and operators cannot do much of anything to improve the performance of the application while it runs on your device.

Decentralization

Diagram. Decentralized network.

On the opposite side of the spectrum lies decentralization, an approach that puts the computing power in the user’s device rather than a data center. In completely decentralized approaches to computing, there may not be a central data center at all and possibly no need for any of the users to even participate in a network.

Decentralization first became possible in IT when microcomputers were popularized by IBM in the 1980s. These machines could perform tasks without a central computer system to support them, which in turn enabled users to operate autonomously. Soon, challenges began to appear with this decentralized approach. To name just a few:

Users stored data in files on their cassette tapes or floppy disks before hard drives became reasonably priced, which often were not backed up or secured properly.

Mismanaged local security could allow data to fall into the wrong hands or even leave the organization on portable drives.

Data created by one user may have been incompatible with other users due to differences in operating systems, application versions, or even applications themselves, such as WordPerfect versus Word.

The benefits of decentralization can outweigh the disadvantages, though. Decentralized systems are able to operate without a network connection because their data and applications are available locally. This is ideal for portable systems more so than stationary desktop computers. Another advantage of decentralization is the lack of a single point of failure, or, perhaps more accurately, each computer is its own single point of failure because the computers do not rely on each other.