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4.1. Sequencing Behavior Overview
This section describes the behaviors associated with the various sequencing processes. SCORM sequencing processes are derived from those described in IMS SS. The descriptions that follow are not intended to replace the detailed descriptions included in IMS SS; instead, they are intended to help distill the primary features and characteristics of the processes. In some cases, SCORM Sequencing extends or alters an IMS SS process. For this reason, the Sequencing Behavior Pseudo Code detailed in Appendix C of this book replaces all of the pseudo code included in IMS SS, and it should be considered normative for a SCORM compliant LMS.
IMS SS includes two data models that apply to each activity in the activity tree – a data model that maintains the state of an activity, and a data model that describes the content developer’s sequencing intentions when an activity is processed. In addition, a state model is defined that maintains the state for each individual activity and the activity tree as a whole. The sequencing processes utilize information from all three models as defined by the Sequencing Behaviors Pseudo Code (refer to Appendix C). The data models and their relation to the activities can be summarized:
Tracking Model (refer to Section 4.2: Tracking Model): Captures information gathered from a learner’s interaction with the content objects associated with activities. This is a dynamic run-time (while the learner is interacting with a content object and the LMS) data model.
Activity State Model (refer to Section 4.2.1 5: Activity State Information): Manages sequencing state of each activity in the Activity Tree and the global state of the activity tree. This is a dynamic run-time data model utilized by the LMS’s sequencing implementation to manage the state of the activity tree during a sequencing session.
Sequencing Definition Model (refer to Section 3: Sequencing Definition Model): Describes how the various sequencing processes utilize and interpret tracking model information to sequence activities to provide the defined sequencing behaviors. Typically, this is a static data model (defined in a SCORM Content Package) describing authored sequencing intentions for a given content organization.
The various sequencing behaviors are independent of one another, but they act on the same three sets of data described above. Each sequencing behavior consists of several processes and subprocesses that exhibit well-defined behavior, but do not directly rely on any of the other sequencing behaviors – that is, one sequencing behavior does not directly invoke another sequencing behavior. The Overall Sequencing Process defines how all of the sequencing behaviors relate to one another within the context of a sequencing session and the sequencing loop (refer to Section 4.3.1: Sequencing Loop).