Key terminology

This document assumes a familiarity with BMC Discovery and as a reminder here are some of the key terminology and concepts that are used throughout this guide:

• Data Aging - Discovered data is regarded as valid at the time of its last successful scan. The nature of IT infrastructure means that frequent, minor changes to configurations, hosts, and software are common. Consequently, discovered data can be regarded as becoming less current with the passing of time. In BMC Discovery when data passes a certain configurable aging threshold, it is destroyed.
• Datastore - All data used by the BMC Discovery system is held in an object database. The datastore treats data as a set of objects and the relationships between them.
• Directly Discovered Data - Data that the Discovery Engine has discovered; it has not undergone any processing beyond simple parsing. Everything that the Discovery Engine finds that might be of interest is stored, regardless of whether it is understood or not. It is stored in a structured form that can be queried and reported on, making it easy to construct certain kinds of discovery reports, and aids in developing new patterns.
• Event - The Rules Engine (ECA Engine) executes rules in response to Events.
• Host - A node in the model which represents a physical or virtual computer system including information about its OS and its physical or virtual hardware. A host is sometimes referred to as an OSI (Operating System Instance). See Host node.
• ID - The ID of a node is a unique identifier for the node itself. If the node corresponding to an entity is destroyed, and a new node is subsequently created for it, the new node will have a different ID, but will have the same key.
• Inferencing - This is the act of drawing conclusions based on other data.
• Key - The key of a node is a unique identifier for the entity that the node represents. However, the key of a node is persistent unlike the node ID.
• Lifecycle - The lifecycle of an entity describes the conditions under which it comes into existence, and the conditions under which it ceases to exist. For nodes in the BMC Discovery model, the lifecycle stages are:
  • Current - The lifecycle stage used to describe nodes which exist in your model. BMC Discovery has evidence that they currently exist in your environment.
  • Aging - The lifecycle stage used to describe nodes which also exist in your model. However, these nodes represent entities that BMC Discovery has not seen in a certain period of time and has chosen to 'age out' of the model. Not all entities that BMC Discovery fails to see evidence for after a certain period of time are aged.
  • Destroyed - The lifecycle stage used to describe nodes which have been specifically marked as destroyed. These nodes are 'destroyed', however, they remain in the model.
  • Purged - The lifecycle stage used to describe destroyed nodes which have been specifically 'purged' from the model. Purging a node means that it no longer exists in the model and has been actually removed from the datastore.
• Node - A node is an object in the BMC Discovery datastore, which represents an entity in the environment. Nodes have a kind, such as 'Host', and a number of named attributes. Nodes can be connected to other nodes via Relationships. Most node kinds have a 'key' which uniquely identifies the entity in the environment.
• Node Kind - The type of a node, such as Host or Software Instance. The default set of nodes and their associated attributes and relationships are defined in the BMC Discovery taxonomy.
• Pattern - Patterns are written in the Pattern Language (TPL). Patterns are responsible for creating and maintaining the model. Each pattern in TPL has a corresponding Pattern node in the model, which is related to the nodes that the pattern is maintaining. Patterns are used to extend the functionality of the reasoning engine.
• Provenance - Meta-information describing how inferred information came to exist. It is generated as Reasoning builds and maintains the model. Provenance information is stored as relationships in the model.
• Reasoning Engine - The Reasoning Engine is an event based engine which orchestrates and drives the population of the different parts of the data model through execution of a series of rules that make up the core functionality of the product. It is extensible through the use of patterns.
• Relationship - The way in which two or more nodes are associated with each other. Like nodes, relationships have a kind, such as 'Dependency' and a number of named attributes. Relationships are linked to nodes via Roles.
• Removal - The concept of taking data out of the model using one or more of the BMC Discovery lifecycle methodologies (Aging, Destroyed or Purged). Removal is the collective term used in this document.
• Role - A node with a relationship to another node acts in a Role in the relationship, which indicates which end of the relationship it is. For example, in a 'Dependency' relationship, one node has the Role 'Dependant' and the other has the Role 'DependedUpon'.
• Rules Engine - This is another term used to describe the reasoning engine. The Rules Engine processes the rules that are generated from Patterns, in order to maintain the model. The Rules Engine is an Event Condition Action (ECA) engine.
• Rules - Rules are small fragments of executable code that run in the Rules Engine. Rules are generated from Patterns when they are activated. Other core rules are distributed with BMC Discovery.
• Taxonomy - The template defining the nodes, attributes, and relationships used by BMC Discovery and stored in the datastore. The BMC Discovery taxonomy also defines how much of the data model is represented in the user interface.
• Trigger - The Trigger for a pattern describes the conditions under which the pattern executes. Triggers correspond to the creation, modification or destruction of node.
  For further information on the BMC Discovery terminology, see the Glossary.