The objects prtAlertCriticalEvents and prtAlertAllEvents have been added to
allow management application to easily determine if there has been a change
to the alert table. Without these counters, the entire alert table must be
read and parsed to determine if the state of the printer has changed. By
using these objects it can quickly be determined whether or not there has
been any change since these objects were last read, and which class,
critical or not, has changed.
It was pointed out to me (thanks Gail) that hrDeviceErrors is "The number
of errors detected on this device." Unfortunately, it does not specify what
is to be counted as an error. For the LaserJet 5Si, we count critical
errors, but another implementation could count all errors. By have
separate, well defined objects, we can avoid the ambiguity.