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Starting with Feature Release 1 for MetaFrame 1.8, Citrix introduced SpeedScreen 3 technology. SpeedScreen 3 enhances the feel of responsiveness of an application and further reduces bandwidth usage. SpeedScreen 3 shows significant measurable improvement over previous versions.
Low bandwidth connections, such as modems, or high latency connections, like satellite WAN connections, can cause frustrations for users when entering data into an application. Previously, when a user typed a character into a MetaFrame-delivered application, the key press had to travel to the server and a signal from the server had to then return to the client before the character was displayed on the screen. For fast typists, this delay was very disconcerting as whole sentences were typed in but did not appear on the screen for several seconds. To solve this problem, SpeedScreen 3 provides predictive text entry allowing users to immediately see the text as it is typed, without waiting for the data to return from the server.
Exam Watch | This technology only works with applications that use the standard Windows API for handling text entry. |
The second major feature of SpeedScreen 3 is allowing the mouse to provide immediate feedback as well. In previous versions, a user could click on an icon in a published desktop and the mouse would appear as if nothing had happened, prompting the user to click on the icon several more times thus launching multiple instances of applications. SpeedScreen 3 provides the user with an immediate change in the cursor to inform the user the action is pending.
High-latency networks can create an elevated sense of frustration for users due to the delays of sending data to and from the servers. SpeedScreen 3 enables users to receive almost instantaneous responses to mouse movements and keystrokes. SpeedScreen can also be customized by using the Latency Reduction Manager from the Citrix | MetaFrame XP program group depicted in Figures 4-4 and 4-5. Figure 4-6, meanwhile, shows the latency reduction settings on the ICA client.
Figure 4-4: The SpeedScreen Latency Reduction Manager
Figure 4-5: Server Properties in the Latency Reduction Manager
Figure 4-6: Client SpeedScreen settings
Delays between entry and echo of mouse movements and keyboard input are one of the primary frustrations client users experience with a high-latency network connection. SpeedScreen features in MetaFrame XP and the ICA client software enable almost instantaneous echoing of mouse movements and keystrokes at the ICA client. Use the SpeedScreen Latency Reduction Manager to customize SpeedScreen settings for a MetaFrame XP server, individual published applications, and input controls within applications. You can save a SpeedScreen configuration file and then deploy the file across your server farm.
To launch SpeedScreen Latency Reduction Manager, from the Start menu, choose Programs | Citrix | MetaFrame XP | SpeedScreen Latency Reduction Manager.
By default, instant mouse click feedback is enabled and local text echo is disabled for all applications. You can enable local text echo on an application-by-application basis only. If you use this feature, the programs to which you apply it must use only standard Windows APIs for displaying text, or the settings will not work correctly. Test all aspects of an application with local text echo in a non-production environment before enabling text echo for your users.
With SpeedScreen Latency Reduction Manager, you can also configure local text echo settings for individual input fields within an application. See the application help for the SpeedScreen Latency Reduction Manager utility for more configuration information.
On The Job | Make sure to test all your applications on a non-productive server and have real users test them when making changes to SpeedScreen settings. Some applications may not perform perfectly with local text echo. |
Exercise 4-2: Setting SpeedScreen Settings on the ICA Client
The client also has some SpeedScreen settings to manipulate. In this exercise, we will enable the predictive text entry setting on our client.
Open Program Neighborhood, then open the properties page to your farm.
Select the Default Options tab and choose the drop-down list in the SpeedScreen Latency Reduction section. Set it to 'On' as shown in Figure 4-7.
Figure 4-7: Client-side SpeedScreen settings
Check the box for local text echo and close the properties page.
For general information about SpeedScreen options, see the online help in the SpeedScreen Latency Reduction Manager. You can deploy SpeedScreen settings for each application or server you configure by copying the entire contents of the %systemroot%\system32\ss3config directory to each server in the farm.
On The Job | Be aware that applications developed using MFC (Microsoft Foundation Classes) generate application window names dynamically and may receive settings even when the application name is in the exception list. This is because the Latency Reduction Manager uses window names to identify items listed in the exception record. |
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