[This is preliminary documentation and subject to change.]
A show reminder application is the application that handles the show reminder, typically by displaying a reminder dialog to the user and/or tuning to the channel displaying the show. This should not be confused with the application that sets a show reminder.
If you set a show reminder using WebTV for Windows, the show reminder application will be Tvx.exe for normal show reminders and Tvwakeup.exe for record reminders. The difference between these applications is that Tvx.exe, which is the executable for WebTV for Windows, simply displays a dialog box reminding the user that the show is about to begin. Tvwakeup, on the other hand, displays a reminder dialog, tunes to the show's channel unless canceled by the user, and starts any record helper applications specified in the registry.
Note Tvx.exe does not display show reminders that occur while the system is suspended. This prevents the reminder from inadvertently waking the display and audio at undesirable times, such as when the user is sleeping.
Tvwakeup.exe handles record reminders that occur while the system is suspended by tuning to the specified channel without waking the audio or video display.
In addition to using Tvx.exe or Tvwakeup.exe to display reminders, you can write a custom reminder application. For example, your custom reminder application can play music or animate the show reminder message.
Note that if you write a custom reminder application, you must also write an application to set show reminders. This is because WebTV for Windows only supports setting show reminders that specify Tvx.exe and Tvwakeup.exe as the display applications.
In addition, a custom reminder application may use command-line parameters other than those specified in Show Reminder Format. If so, the application that sets the show reminder must support the custom command-line syntax.
For information about creating custom applications to set show reminders, see Scheduling Show Reminders.