As with many “new” technologies, (like cloud computing) some have roots in early computing technologies. Take the concept of thin computing. Before the days of powerful desktop hardware, computer systems were comprised of a powerful mainframe computer and much less powerful terminals. The mainframe would do all the processing of data and the “dumb terminals” would simply display the input and output. This growing trend in business computing, heralds the days of the mainframe with very fast servers providing the data storage and processing for low cost, low performance clients.

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Fat Clients
Today, most people have fat clients – computers with fast processors (to quickly crunch data), large hard drives (to store applications and files), memory (to run applications), and video cards (to display complex and 3D graphics). A thick client can be a desktop, laptop, netbook, or tablet computer. A thick client stores and runs its own operating system and applications. It is made of expensive technology like multi-core processors, lots of RAM, large hard drives, and video cards with dedicated processors and memory.
Thin Clients
Thin clients are terminals that run an operating system and some applications. They connect to servers which host data and other applications. Thin clients are capable of storing some files locally and running some applications but rely on the server to store large data files and complex applications. They can be found as all-in-one (monitor and computer in one box), desktops (very small form factor), and laptops.
Thin clients have slower processors, less memory, and less capable video cards than fat clients. However, they are cheaper. They also may not have any moving parts – no spinning hard drive and no cooling fans – due to flash memory and low power processors. Because of this, they can safely operate in more harsh environments than fat clients.
Zero Clients
A zero client is a terminal which does not run an operating system or applications. It runs a kernel which initiates the hardware and networking components and requires the servers to provide all the data and applications for the user. Like thin clients, zero clients can be found as all-in-one (monitor and computer in one box), desktops (very small form factor), and laptops.
Like thin clients, the hardware is cheaper and can operate in harsher environments.
Benefits of Thin and Zero Clients
The benefits of thin and zero clients include cost savings, ongoing upkeep, centralization, scalability, and reliability. Businesses can save money with thin and zero clients because they cost less per device than fat clients. They also use less power and create less heat than fat clients. However, some of this cost is offset due to the increased cost of the server infrastructure needed to host the data and processing.
Ongoing maintenance is easier with thin and zero clients because they contain very little data. In the case of a failure, a technician will simply swap the thin or zero client with another device and the data and applications on the server are not affected by the client failure. In addition, software upgrades are much easier because only the server side needs to be updated and not each individual client. However, the server maintenance is more complicated due to the robustness of the server environment. So while the client side may require less people to maintain, the server side may require more.
Since the servers host the data and applications for the clients, everything is by nature centralized. This provides easier backup management and data security.
Scalability is accomplished due to the fact that the servers can host multiple clients and by adding more servers more clients can be hosted. The adding of servers can be done with minimal impact to production. Likewise, adding additional clients can be added as long as the servers can take on the additional load.
Since thin and zero clients can be easily swapped out after hardware failure and servers are centralized and scalable, this creates a more reliable environment. The servers are also more reliable than fat clients due to the built in redundancies of the actual server hardware and the ability to set sever clusters where multiple servers work as a team to host clients. In the event of a server failure the remaining servers can assume the workload of the failed device with minimal impact to the users.
Challenges to Thin and Zero Clients
Like everything in technology, thin and zero clients are not for everyone. First, the servers are expensive so replacing three fat clients with three zero clients will not be cost effective. Second, a proper data center and networking infrastructure is necessary to host the servers and client access. Third, not every application can operate in a thin or zero client environment. Fourth, the server is a single point of failure. If the server side fails, all the clients are impacted.
Conclusion
There are many benefits to thin and zero clients including cost savings, ongoing upkeep, centralization, scalability, and reliability. However, they are not appropriate for every situation and critical examination must be completed before jumping in with two feet.
Resources
HP Thin Clients: http://www8.hp.com/us/en/hp-information/thin-client-solutions/index.html
Citrix: http://www.citrix.com/lang/English/home.asp
Dell Thin Clients: http://content.dell.com/us/en/business/d/sb360/fx170-thin-client
Wyse: http://www.wyse.com/products/hardware/thinclients/index.asp
Do you have experience working with thin or zero clients? Please share your thoughts and experiences below in the comments section.