Thick and Thin clients: definition and difference

In computer technologies the term «client» means software or hardware that interacts with the server in order to receive data or perform some actions. Client is an important part of the client-server architecture. The great example of clients are web-browsers. They serve as the web-clients and send requests to the web-server, receiving the needed web-page in turn. 

Client-server architecture has two types: thick and thin. Also there are architectures that combine abilities of thick and thin clients – hybrids.

What is a thick client?

Thick client is a client that holds the requested operations independently, so that without the help of the central server. Central server in this type of the architecture can be used as the data storage, the processing and display of which is transferred to the working machine of the client.

Thick client is a working station or PC that works from under control of its own OS and has a full toolbar of the program software in order to provide the user with the tasks.

Advantages of the thick clients:

• wide functionality;
• multi user mode;
• offline work mode;
• fast action;
• minimizing dependence on expensive and complex servers.

Disadvantages:

• every working machine needs constant maintenance;
• individual hardware upgrade of each client to the level of applications that will be used;
• the possibility of problems with remote data access;
• large distribution sizes;
• dependency on the platform for which the client was developed.

What is a thin client?

Thin client is a type of client that transfers the task of data processing on the server, without using its processing abilities. The processing resources are quite restricted and they are used only for launching the needed application, using for example, a web-interface. 

One of the bright examples of using a thin client on a computer is a PC with a web-browser that is used to work with web-applications. The peculiarity of thin clients is the usage of terminal mode. In this case, the terminal server is used to send and receive the data of the user which is the main difference from the thick data processing on thick clients.

Alongside with usage of the software variant of the thin client, there are also hardware versions of thin clients. These devices may not have their own HDD, however they use a special local OS, the main task of which is to provide the connection with the server that will help in the future solve all user’s requests.

Advantages of the thin clients:

• less user hardware and software maintenance;
• reducing the risk of malfunctions, since files and applications are stored on a central server;
• less hardware requirements compared to thick clients.

Disadvantages:

• common point of failure: If a server fails, all users will be affected;
• inability to work without a network connection;
• with a large volume of work with video and audio data (especially creation and editing), the centralization of thin clients can greatly reduce the performance of the central server.

Difference between thick and thin clients

The main difference between thin and thick clients is the way information is processed. The thick client works with data using its hardware and software capabilities, and connects to the server only to receive data from the database. Thin clients, in turn, use the provision of a central server to process information, providing only the necessary interface for user work. Therefore, already outdated PCs can be used as thin clients.

Comparison of thick and thin clients by main characteristics

Independence. Thick clients work independently of the central server and use their resources. Thin clients are almost completely dependent on the central server and the resources available on it.

Resource consumption. Thick clients use more local resources because they perform all the functions themselves. Local resources of thin clients are intended only for creating a communication session with the server.

Data storage. Thick client user data is stored locally on the work machine.

Network connection. Thick clients can work offline, thin clients need constant access to the Internet.

Deployment process. Thick clients require large costs, because each working machine needs to be individually updated for specific user tasks. Thin clients are not that expensive, so very basic PC hardware can be used. The main expense when working with thin clients will be a high-performance server and its settings.

Security. Increased security issues may arise when working with thick clients due to the high risk of data loss on individual workstations. Thin clients are considered more secure because the data is stored on the server.

Examples of use and applications

All users, to one degree or another, meet with thin and thick clients in the process of work or simply use a PC to solve their tasks.

From a hardware point of view, a thick client will be considered a working machine that the user uses to implement his tasks. Such a PC is equipped with the necessary hardware to solve the set goals. A thin client can also act as a separate working machine. Such thin clients are very compact, and use passive cooling. Often, thin clients are used as office work machines.

On the software side, examples of thick clients are collaboration programs and applications, especially if they are installed and processed on a specific computing device. Some examples of these applications include Microsoft Office 365, Adobe Creative Cloud, Yahoo Messenger, and Microsoft Outlook.

Web browsers and web applications such as WordPress, Google Docs, and online games are examples of thin clients. Devices used to stream media, such as Chromecast and Apple TV, installed with streaming applications such as Netflix or Spotify are technically examples of thin clients. Google and Yahoo search engine sites can also be classified as thin clients.

When creating thin clients, Thinstation is often used. It is a specialized Linux distribution for initialization and working with thin clients. The distribution itself is small in size and provides the ability to work with various protocols for remote access (RDP, telnet, SSH, Citrix ICA and others).

The choice of which client to use often depends on what the user's goals are, and what hardware and software resources are available. Based on the pros and cons of implementing each approach, you can choose the most optimal option.