Windows PCs can run almost any type of software. They are cheap, powerful and office workers are familiar with them. They are also prone to virus attacks and need constant patching with security updates. Local files need to be backed up. Thin clients promise to reduce such problems.
What is a Thin Client?
Thin clients, dumb terminals and network computers are roughly the same. The main program runs on a central server. The end-user controls the program over the network, using a thin client. Data files are also stored on the server. Mainframe terminals, Unix telnet, Unix X Windows, and many web applications; are thin clients.
Some client-server applications aren't strictly thin client solutions, because a new application-specific client is installed on the PC for each new application. Microsoft Outlook and Microsoft Mail are fat clients, with the email client running on the local PC. The emails are also stored on the PC's hard disk. Gmail and Hotmail are thin clients.
A good way to understand thin clients (and to persuade people to use them) is to look at the many thin client web applications: web mail, Facebook, Google Docs, web file sharing. There's no need to install additional software, and users can login from any PC.
Thin Client Advantages
A thin client solution means fewer computers to maintain. Most of the administrative effort can be concentrated on a few servers:
- New software application versions can be rolled out all at one go. No need to worry about some users still running the old version and causing problems. No need to go to each PC and install manually.
- No need to worry about testing new software on multiple OS versions and Service Packs (Windows XP, Vista, Windows 7 Enterprise, Windows 7 Ultimate).
- Less (but not zero) need to implement anti-virus solutions for all desktops.
- Less effort configuring PCs for new staff.
- Easier lock down of end-user desktop security settings.
End-users also benefit. They:
- Can work from any workstation without worrying about copying out their local files. A non-functional PC (due to virus attack, hard disk failure etc) is no longer a big deal. Just use another thin client.
- Don't need to maintain their own PCs: defragmenting the hard disk, backing up their local files.
Thin Client Disadvantages
There are downsides to thin clients that need to be considered:
- To support many simultaneous users on the same server, expensive multi-processor machines with lots of RAM and large hard disks are needed.
- The server becomes a single point of failure that can disrupt the operations of the entire enterprise. Redundant fail-over clustering hardware or other high availability architectures are necessary.
- Not all commercial applications are suitable for thin client deployment. Alternative applications might be required.
- Will cause increased network traffic.
- Network delays (latency) can make response times too slow to be practical for some applications.
- Reliable high speed network communications are needed.
- Might not be suitable for mobile users (VPN support required).
- End-users need to accept reduce functionality. They cannot install their own applications.
- Local printers, scanners might not be supported.
Thin Client Solutions and Standards
The simplest thin client solution is a web application. The thin client is a web browser and the server is a web server running a CGI application.
Other solutions are:
- Microsoft Remote Desktop Services (previously called Terminal Services).
- Citrix (XenDesktop, XenApp, XenServer; previously called Presentation Server).
- Linux Terminal Server Project (LTSP).
A server application needs to be able to run inside one of the above solutions, to be deployed as a thin client application.
Thin client hardware manufacturers – HP (Compaq, Neoware), Wyse (Winterm), IGEL etc – support some or all of the above systems. Software thin clients, running on standard Windows PCs, are also available.
Dedicated Hardware Thin Client Terminals and Operating Systems
The thin client still needs an operating system to work. However, a small lightweight (and presumably less virus-prone) OS can be used. The thin client can be considered a hardware appliance, like a video recorder or mobile phone, not a general purpose computer.
For example, Wyse offers thin clients with the following operating systems:
- Wyse ThinOS
- Windows CE
- Linux
- Windows Embedded Standard
- Windows XPe
- Diskless (boots over the network from the server hard disk)
How to Implement and Deploy Thin Clients
There are different ways to deploy thin clients, different degrees:
- Thin clients as desktop replacements only, leaving Windows notebooks for mobile users.
- Thin clients for some staff only, depending on job requirements.
- Thin client servers, but with thin client software running on generic Apple Macintosh, Linux or Windows PCs.
- Web applications only, no dedicated thin client software.
DesktopLinux.com has details of a business case study involving a Linux thin client implementation.
Related to thin clients but slightly different, is "desktop as a service" solutions such as VMware View (previously called VDI) and MokaFive. Dr. Monica Lam from MokaFive has a criticism of thin clients.
Yuen Kit Mun - Kit Mun is a self-confessed information junkie, reading an average of a book a week over the past two decades. His growing Internet ...
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