What is a Thick Client and Thin Client? 7 client types reviewed


what-is-a-thick-client-and-thin-client

When I was looking at replacing my PC for a thin client, I was slightly confused when salesperson used the term thick client to describe my PC.

What is a thick client and thin client? A thick client does application processing itself by running applications, whilst a thin client relies on a server to run applications on it’s behalf. The thin client only needs a stripped down operating system, so it can capture keystrokes, mouse movements and display changes sent from the server.

Let’s take a detailed look at what thick client and thin clients are.

What is a Thick Client?

Thick clients also known as fat clients, can run applications themselves, such as word processing, spreadsheets to web browsers. These applications are installed on the thick client device and use the processing power, memory and storage of the thick client to work.

The thick client accepts the users mouse movements and keystrokes as input to the applications being used and then sends updated changes to the users monitor.

So, when the user presses the right button on their mouse, the thick client realises this input and sends this to the application. The application opens its context menu and the thick client updates the users display, showing the context menu.

Desktop PCs

Applications are installed on Desktop PCs and use the processing power, memory and storage of the Desktop PC to work.

Laptops

Applications are installed on laptops and use the processing power, memory and storage of the laptops to work.

Tablets

Applications are installed on tablets like Apple’s iPad and Android Pixel tablets. The applications use the processing power, memory and storage of the tablets to work.

Smart Phones

Applications are installed on Smart Phones like Apple phones and Android phones, using the processing power, memory and storage of the Smart Phones to work.

What is a Thin Client?

Thin clients cannot run applications themselves and rely on remote powerful computers known as servers to do their processing. Applications like word processing, spreadsheets to web browsers are installed on the servers and use the processing power, memory and storage of the servers to work.

The thin client accepts the users mouse movements and keystrokes as input and sends the to the remote server where the applications are. The remote server then sends updated changes to the thin client and the thin client sends these changes to the users monitor.

So, when the user presses the right button on their mouse, the thin client realises this input and sends this input to the remote server where the application is.

The application on the remote server opens its context menu and the remote server sends the updated change in the display to the thin client. The thin client then updates the users display, showing the context menu.

Terminals

Terminals like Dell Wyse 3040 and HP t430 are specific thin client devices with minimal hardware and form factor (size). They have a microprocessor (CPU), memory and can have some local storage, typically flash memory. They run an operating system like Microsoft Windows IoT, or a custom Linux based operating system like ThinStation.

Zero Clients

Zero clients are also known as ultra thin clients and don’t have any processing units, memory or any storage. They don’t have any operating system either and instead they have special microchips to decode and render remote communications sent to and from the remote servers.

The decoding and rendering microchips work with one of the remote communication protocols like Citrix ICA, Microsoft RDP or VMWare PCOIP.

Repurposed PCs

Low-performance hardware (a thin client does not need a high processing capacity), such as out-of-date computers can be used to create thin clients, making thin client an ideal technology for institutions that still use old computers or have limited maintenance staff and a tight budget.

As most thin clients run remote desktop software, such as Citrix Workspace (formerly Citrix Receiver), VMWare Horizon Client and Microsoft Remote Desktop Services client (RDS), the same remote desktop software can be installed on repurposed PCs. Which means that you will still be in a position to see the familiar desktop environment that you are accustomed to.

Difference Between Thin Client and Thick Client

The table below can help to give a clear picture of the differences between thin clients and thick clients:

 Thin ClientThick Client
DefinitionSoftware that depends on a remote server for its features. An example of a remote server is a cloud platformThe software which allows most features to run directly on a device

Network LatencyA fast and robust network connection is required for it to function properlyIt may operate with a slow network connection or even no connection at all
OfflineFunctions don’t workFunctions normally work in most cases
DataData is stored in serversData is stored locally
Intensive ApplicationsGraphically Intensive applications can record poor performance as they rely on the speed of the networkAs there’s no network reliance, intensive applications can perform better
Workspace ControlThe user’s workspace is controlled centrallyThe user can set up their workspace as they wish (suitable privileges required)
Local ResourcesUtilizes limited local resources, such as memory, disk, and computing powerConsumes more local resources
Centralised ManagementCentrally managed and controlledManaged locally with some centralised management
Thin vs Thick client comparison

Network Latency

Typically, thin clients aren’t convenient for all situations. That is because they have to be connected to a network most of the time and if this network doesn’t have the capacity to deal with the information sent by the thin client to the remote servers, the thin client user experience suffers, as the user is unable to work productively.

The screen refreshes slow down, so the delay in updating any changes like the mouse position, keyboard inputs take several seconds instead of milliseconds.

With thick clients the network latency only slows down any applications using the network (like pulling data from a remote server into a spreadsheet), leaving the locally installed applications to function.   

Offline

Without network connections the thin client cannot connect to the remote servers, so they themselves become unusable. Users simply won’t be able to login as the thin clients connect to authentication services and without network connectivity, these will be unavailable.

Thick clients on the other hand, can have cached credentials, so even without a network, it’s still possible to login. As the applications are locally installed on the thick client, they are still usable.

Data

Thin clients don’t have any storage capability for storing user data, so all this data stays on the remote servers the thin client devices connect to. This makes it also easier to back up data as there’s no need to include any of the thin client devices in a backup strategy as you would with thick client PCs.

Intensive Applications

Graphically Intensive applications require good network connections as there are many screen updates to and from the thin client to the remote servers. Without a good network connection, these updates slow down and instead of taking milliseconds, they start to lag, taking seconds instead.

Workspace control

User can have far more control over their workspace on a thick client, when compared to a thin client. They can, subject to privileges, install applications, change display settings and do a whole host of other customisations.

Whilst the thin client user has a very limited ability to customise their desktops and can’t install any applications themselves. As the applications need to be installed on the remote servers and these have other thin client users on them.

Any application installation could disrupt these other users and if done incorrectly cause the remote server to crash. Specialists with skills in installing applications on remote servers are required instead.

Some people may also be reluctant to give up their control over desktop applications, therefore, it is essential to assess the functionality of thin clients to see if they are right for your needs.

Local Resources

Thick clients utilise more of their local resources like processing power, memory and storage when used, whilst thin client utilise more of the resources of the remote servers they connect to.

Providing only minimal local resource utilisation to take mouse and keyboard inputs and update screen refreshes on the display. This means the thin client doesn’t have to be as powerful as the thick client to work effectively.

Centralised management

A thin client has a centralized set-up, which makes it easy and convenient to manage and maintain. This makes it also easier to troubleshoot, administer the network, and even monitor other features in the system.

Where are thin clients used?

Thin clients make an excellent choice where using thick clients like PCs becomes difficult to maintain. Remote offices are good candidates for thin clients, as well as call centres to retail settings, where the reliability of thin clients makes them easier to support.

Cloud Desktop as a Service (DaaS)

With the popularity of cloud computing showing no signs of slowing down, the thin client makes an excellent candidate to leverage Cloud Virtual Desktops. These desktops are run in the cloud on powerful servers and the thin client connects to these remote servers and displays the interactions between the user and the virtual desktop.

Conclusion

Thin clients act as dumb terminals for more powerful remote servers whilst thick clients can act alone, allowing applications to work with poor or limited network connectivity.

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