Secure Global Desktop Administration Guide > Applications, documents and hosts > Using shadowing in the classroom

Using shadowing in the classroom

You can use Secure Global Desktop shadowing to create a "virtual classroom" where the "pupils" in the classroom shadow an application being demonstrated by a "teacher".

To be able to do this, you have to create a teacher's application object and a "classroom" application object.

Creating the teacher's application object

1. In Object Manager, create a new Windows or an X application object.
2. Configure the object how you want.
3. On the Advanced attributes panel, type one of the following in the Login Script box:
   • unixclass.exp if the application is an X application.
   • winclass.exp if the application is a Windows application.
4. Click Apply.
5. Select the application servers that can run the application, by dragging host objects on to the Hosts tab of the application object.
6. Add the application to the teacher's webtop by dragging the application object on to the Links tab for the teacher's person object.

Creating the classroom application

1. In Object Manager, create a new X application object.

   Note The classroom application is an X application even if the teacher's application is a Windows application.

2. In the Application Command box type:
   
   /opt/tarantella/bin/bin/ttashadow
3. In the Arguments For Command box type:
   
   -readonly -silent -pointer $SHADOWDISPLAY
4. From the Color Depth list select 16-bit - thousands of colors.
5. On the Advanced attributes panel, type pupil.exp in the Login Script box.
6. On the Advanced attributes panel, type the following in the Environment Variables box:
   
   MYCLASS="TFN_name_of_teacher's_application"
   
   for example, MYCLASS=".../_ens/o=Indigo Insurance/ou=Finance/cn=XClaim"
7. Configure the application object in any other way you want.
8. Click Apply.
9. Select the application servers that can run the application, by dragging host objects on to the Hosts tab of the application object. The ttashadow application is only available on hosts where Secure Global Desktop is installed.
10. Add the application to the webtops of all users in the class by dragging the application object on to the Links tab for the person/profile object(s).

Notes

• The teacher must launch their application first, then the pupils launch their classroom application to shadow the teacher.
• The classroom can only shadow Windows or X applications.
• Only one person can use the teacher's application at any one time. If more than one person starts the teacher's application, the classroom will shadow the application that was started last. For this reason, we recommend you only give the teacher's application to one user. If you have several teachers, create separate application objects for each of them.
• The classroom application must have a color depth of at least 16-bit.
• The size of the classroom application should be at least the size of the teacher's application. We recommend the classroom displays in an independent window.
• When the teacher starts their application, information is stored on the Secure Global Desktop server about which application can be shadowed by the classroom. This information is not copied to the other members of the array. This means that if the classroom application is launched on a different Secure Global Desktop server to the teacher's application, the classroom launch will fail because the information about which application can be shadowed will not be available. You can use locations to guarantee that the teacher and classroom applications are launched on the same Secure Global Desktop server. You must set the location of the host objects and the Secure Global Desktop server. Otherwise, we recommend you only use classroom shadowing in a single server Secure Global Desktop array.

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