The SPIDER system is organised into clusters. Each cluster represents a degree or a series of related degrees, which allows administration and management of classes and content to be handled by different departments. For example, all pharmacy related content is in the pharmacy cluster, chemistry content in the chemistry cluster and so on, with each cluster having its own administrator, sub-administrators and editors in charge of management and control of their own classes and materials.
The cluster you belong to determines a number of defaults, such as the classes you see on the myClasses page. Student users can switch freely between clusters via the mySettings page, but would normally remain in the cluster that relates to their degree. As staff users may have admin or editing rights, they can only switch to other clusters if their home department belongs to more than one cluster.
The availability of clusters is one of SPIDER's unique features. It allows for much finer control and better organisation of content than typical VLEs which have a very flat structure, a single layer of classes controlled by tutors. There may be hundreds or even thousands of these classes, but there is no unit or department structure to allow for sensible grouping of classes and their control.
SPIDER's cluster system provides an extra level of heirarchy that allows for devolved administration by allocating each class to a department within a cluster. Administrators within the cluster then have complete control of their own classes and content, but have no control over those in other clusters. At the same time student users are able to view classes and content across cluster boundaries.
As a result of this cluster being available, many of SPIDER's tools have the flexibility to operate at both the class and degree/ programme/ unit level. For example, staff users on SPIDER are able to target news items at several classes in their cluster or even at year level. This news will only be seen by students in the matching cluster - so if a Pharmacy lecturer were to post news for year 1 pharmacy students, this wont be seen by chemistry or physics students. However, if the target is a class code (e.g. a mathematics class taken by chemists and pharmacists) the news will be seen by anyone in any cluster who has the code set in their news filter.
In addition the user object exists within a cluster, allowing suitably authorised users to view all the data corresponding to a user in their cluster. This would allow a year co-ordinator to see all a student's results across all their classes without having to own or be a tutor in every single class that the student is taking.