Overview - Brief Description of Feature

This feature supports the tracking of device i/o history and device adverse event history. History trace buffers are allocated per-device.  In addition, an 'all devices' history buffer is kept so device events can be viewed/analyzed relative to one another..

Problem - What Problem Does the Feature Solve?

This feature provides access to the device events that occured leading up to a problem or leading up to a monitoring session.   Separately, a list of adverse device events is kept with the goal of collecting information on failing or marginal hardware.

Solution - Short Description of How the Feature Works

This feature monitors all POS device I/O and keeps a history trace buffer of all meaningful events.  Normally, this information is kept in a wrapping, circular memory trace buffer.  It can be retrieved at any time though the management APIs and can be extracted from snapshot or full terminal dumps.

In addition to device-specific events, each history queue may also contain one or more time/date synchronization events. These events allow the clock time to be displayed accurately for each event.

The following graphic shows an example from the InSight UI of the 'all devices' event history: