Citrix Independent Computing Architecture Client

In Chapter 1, I mentioned ICA as the technology from Citrix Systems that enables use of the WinFrame multiuser operating system. In this section, I also want to mention ICA client software while reviewing other available technologies. In the next chapter, I ll talk about ICA in more depth.

The ICA client serves as a general-purpose presentation services protocol for Microsoft Windows. Basically, any device having an ICA client embedded or installed on it can run applications written for the following platforms:

ICA client software runs on any computer.

• Windows NT (32 bit)
  
  
• Windows 95 (32 bit)
  
  
• Windows 3.x (16 bit)
  
  
• MS-DOS text
  
  
• OS/2 text
  
  
• POSIX text
  
  
• X Window System applications (used with emulator software)

The ICA protocol presents only the user interface on the client machine, while keeping all application execution on the server. This provides a thin-client software solution since no application execution is performed on the client. ICA also delivers true location independence by running the Windows operating system and the application program at one location (at the server) and displaying the program s user interface somewhere else (at the client).

Conceptually, ICA is similar to the X Window System protocol. ICA allows an application s logic to execute on a WinFrame appli- cation server, while only the user interface keystrokes and mouse movements are transferred between the server and the client device across any network or communications protocol, resulting in minimal client resource consumption. (See Figure 2-9 on page 45.)