An interesting footnote showing how research company IDC defines a Disk Storage System.
It is seen as a set of storage elements, including controllers, cables, and (in some instances) host bus adapters, associated with three or more disks. A system may be located outside of or within a server cabinet and the average cost of the disk storage systems does not include infrastructure storage hardware (i.e. switches) and non-bundled storage software.
The information in this quantitative study is based on a branded view of the disk storage systems sale. Revenue associated with the products to the end user is attributed to the seller (brand) of the product, not the manufacturer. Original equipment manufacturer (OEM) sales are not included in this study. For example, Hitachi Data Systems (HDS) sales do not reflect their OEM sales to Sun Microsystems and Hewlett-Packard.