Herold
The Herold system is designed for IT staff monitoring the applications working within the net. It stores event, error logs and images of the current application condition, enables the warning mode for administrators, and analyzes the course of actions.

The Herlod system consists of:

	Monitor - a program which receives and stores messages,
	Agent - a program which intermediates in passing on the messages,
	Viewer - a program designed for monitoring and displaying the messages and states.

An application monitored by the Herold (which will be called the "Sender" from now on) sends the messages to the Monitor through the Agent. There are three main types of the messages the Sender can sends:

	event - a message destined for the event log. It informs about the facts, which are important from the administrator point of view or about application errors,
	state - a message describing in what state the Sender is actually in. The Monitor stores the current state for every Sender. It means that every following state overwrites the previous one,
	activity - a message informing that the application is active. For the indicated groups of the Senders, the Monitor checks if the application shows activity in due course. If not, it inserts into the log the information about a lack of response - this kind of event is recognized as a fatal error.

Sending a message by the Sender consists of passing it on to the Agent. The Agent is responsible for the communication with the Monitor. If the communication is broken (e.g. there's no connection with the Monitor) the Agent records the messages in the temporary file waiting to reconnect. After it is reconnected successfully all the recorded messages are sent to the Monitor. It doesn't apply to the messages of a state and activity type due to their temporary status. After a reconnection only the latest message of a state and activity type are sent.

The Monitor is a active all the time. It receives the messages from all the Agents. Every message along with the Sender information is recorded in the database (Interbase, FireBird).

The Viewer enables to browse the state and event messages from the Senders. The messages of the activity type are visible as a part of the state. There are two types of the Viewer available. One of them is designed for the administrators and enables the filtering of the incoming messages, creating definitions of different cross-sections of the views, events, and conditions. The other one is an application enabling a person without the administrator's rights to browse the state data indicated of the specified Senders.