User's Manual

Controllers 81
7
Controllers
This section describes the controllers supported by Storage Management as
well as the different controller features.
What is a Controller?
Most operating systems do not read and write data directly from the disks, but
instead send read and write instructions to a controller. The controller is the
hardware in your system that interacts directly with the disks to write and
retrieve data. A controller has connectors (channels or ports) which are
attached to one or more physical disks or an enclosure containing physical
disks. RAID controllers can span the boundaries of the disks so as to create an
extended amount of storage space – or a virtual disk – using the capacity of
more than one disk.
Controllers also perform other tasks, such as initiating rebuilds, initializing
disks, and so on. To complete their tasks, controllers require special software
known as firmware and drivers. In order to function properly, the controller
must have the minimum required version of the firmware and drivers
installed.
Storage Management supports different types of controllers. If your system
has a supported controller, the controller is displayed by expanding the
Storage object in the tree view. You can select the controller to display tabs for
executing controller tasks and viewing controller properties.
Different controllers have different characteristics in the way they read and
write data and execute tasks. It is helpful to understand these features to
most efficiently manage your storage. The following sections describe the
supported controllers and their features.