I have numerous old PCs at home, which are now to today's standards, pretty unusable (Pentium 166, Pentium 200, Celeron 333 etc). I mean they even struggled to load most of today's websites with ease, and they ran legacy OSes (Win9x, OS/2) which I had no use for anymore. Therefore, I decided to convert them to thin clients.

Server Specs

As the system will only really be used by around 1-2 users at a time, the server really isn't that powerful:

Pentium III 850Mhz 100Mhz FSB
768MB PC133 RAM
7200RPM 80Gig Seagate Barracuda HDD
Via Apollo Pro 133 Chipset

Initial Terminal Server Configuration

The server is running Microsoft Windows 2003 Server SP2, as I wanted a Windows-based thin-client system, and I also wanted to use other Windows features such as Active Directory, for my other Windows fat-clients. First of all, I installed the OS onto the server, and configured drivers etc. Next stop was to install Terminal Services and Terminal Server Licensing from Add/Remove Windows Components. Terminal Services is the multi-user thin-client server solution on Windows 2003, and comes with the default RDP protocol. You must install any application software AFTER installing Terminal Services, NOT before. Fairly easy so far.

Citrix MetaFrame Configuration

I've used the RDP protocol many times before, and it is not that great at all. However, I had seen the Citrix ICA protocol used before, and was amazed by its responsiveness and speed. Therefore, I definately wanted Citrix MetaFrame/Presentation Server on my server. I managed to get hold of a copy of Citrix MetaFrame Presentation Server XP Release 3. Beware, it can be quite a dog to install and manage. Installation steps:

Install or Reinstall IIS for Web Interface
Install the included Java Runtime, not the latest version
Install Microsoft Visual J#.NET Runtime
Install Presentation Server Console
Install Web Interface
Install Presentation Server

Next, go into Presentation Server Console, and add a new published application called Desktop, and select the type as Desktop. The Presentation Server walkthrough wizards make the whole process fairly straightforward. Next, go into Connection Configuration Tool, select the ICA connection, right click and select Edit. Click the button labelled ICA Settings, and Uncheck the box 'Launch only published applications', and hit OK/Apply, etc. You should be able to connect to your Citrix server, by launching the web interface from another computer, by going into the web browser, and typing the name of the server. You need to make sure that you have the Citrix Presentation Server Client/Citrix XenApp Plugin installed. You can also create .ICA files from the Presentation Server Console for each individual published application. ICA files are like small configuration files, which when double-clicked, launches the Citrix Client, and tells it what to connect to, etc, much like a .RDP file.

Now the fundemental configuration on the server is complete, it's now time to decide what to do with the thin-clients

Thin-Clients

You have a few options for thin-clients:

Buy specifically designed thin-clients, like those from HP, Wyse
Use the existing OS on existing PCs to connect to the server
Bypass the existing OS on the PCs, and make the PCs boot a universal Linux image off the network

I went for options 2 & 3. Option 2 seemed most attractive for Laptops, as they would be using wireless network adaptors, meaning they couldn't boot off the network anyway. Also, the power management features of the laptops are fully supported under Windows. To make these appear as thin clients, I simply created a simple application with a logo, and two buttons, Connect and Shutdown. I set Windows 2000 to autologon to an account named LocalUser, and defined in the registry, the application I made as the default shell, instead of explorer.exe. Clicking Connect would simply launch an ICA file to connect, and pressing Shutdown did, well, I'm sure you can guess.

However, for normal desktop PCs, option 2 wasn't so attractive, as each PC had different hardware etc, and creating customised Windows installations for each PC would be a real pain in the arse. Therefore, I opted for an excellent, uber lightweight Linux distribution called ThinStation Linux. My build includes the RDP client rdesktop, and the ICA client along with the necessary drivers for each computer. In total, it comes to 8MB in size. To get PXE Network booting working on the server, read this