During longer periods without user feedback users may become uncertain whether the system is still working. System tasks, which do not indicate progress may have the same effect on users.

The sample screenshot shows several types of activity indicators. At the top right corner of the screen, a keep-alive-icon indicates by flashing that the system is still functional. In the dialog, the upper notification demonstrates a progress bar for an event with a known end. The lower notification showcases an ongoing event where the exact duration is unknown.

Context

When performing an action, operators need to know the progress of the operation.

Forces

Activity indicators may be too distracting for users or even block the entire interface, e.g., when designed as modal dialogs. This shall be avoided at all cost.

Solution

The system shall display an animated life indicator in the status bar using a flashing colon in a 0.5 second interval. Additionally, there are two types of progress indicators:

• if the duration of an event can be calculated, e.g., when the size of a download is known, a progress bar is used
• if the duration cannot be calculated, e.g., when waiting for a
  remote system to respond, an animated hourglass is displayed as long as the activity lasts

Usability impact

Users will gain trust in the system because system feedback is available for all operations.

Safety impact

For users it is important to know whether the system is still “alive” or if it has stopped working. For longer lasting activities users need to know the progress. In the meantime, access to safety-relevant functions must be possible without obstruction.

Your opinion!

Feel free to provide your comments, reports of usage of this pattern, or feedback in general!