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Copy Screen Images
Using this function, screen images are displayed on one workstation and
automatically copied to another workstation. This allows quick exchange of
visual information between users at two different sites.
The Copy Screen Images function provides the capability for a user at one
display device to view the screen images being processed at a second display
device. Through commands or menus, the user specifies that all screen images
displayed on a specific device are to be copied to some other display. The
display station being copied is in control and is input capable. It is called source
device. The display station to which the controlling terminal's screens will be
copied is a display only device. It is called the target device and has no input
capability. The user can also specify that screen images be sent to database
output file.
This function is implemented using a variety of existing CPF capabilities. Job
Control, Message Handler, Data Management, Workstation Management, and
Queue Management functions are used to obtain control of the source and target
display devices and to communicate between processes associated with each
display. Display station data streams are captured by the system and copied to
the target display. Although this function uses existing support, the algorithm for
accomplishing this task is unique.
A typical flow for the copy screen image function is shown in the figure. The
processing during this flow would be: 1. The STRCPYSCN command is issued
from an authorized user at workstation "C" requesting that the screen images
from workstation "A" be copied to workstation "B". 2. An inquiry message is sent
to the user on workstation "A" asking if it is acceptable to perform this operation.
3. The user on "A" replies "Y" to approve the start of the operation. The user on
"C" is informed that the operation has successfully been started through a
completion message from the command. 4. The user on "A" subsequently hits
the enter key. 5. The screen image of workstation "A" is trapped by the system.
6. The screen images are updated: a. The image captured in step 5 is displayed
on workstation "B". b. The application processing screens for workstation "A"
send the next screen to "A". Steps 4, 5, and 6 are repeated until screen image
copying is cancelled. 7. The ENDCPYSCN command is issued from workstation
"C" to terminate the copying process. 8. An informational message is sent to the
user on the source device. 9. The target device ("B") is returned to the original
screen, which will either be a sign-on screen or blank (if the device was not in a
sub-system).
The unique characteristics of the Copy Screen Image processing include: *
The observer at the target device does not need to sign-on to the system *
Flexible control mechanisms and specifications of source and target devices *
Disabling entry on target device, except to cancel operation * Capturing and
displaying of end user entered data * Indep...
