The Oracle terminology is ambiguous. It might refer to disk platters where the data file is stored on the outer tracks. Or the terminology means something to a specific vendor's disk arrangement where faster disks are stored in a specific location in the cabinet.
With the XP24000 (or any model of XP, or virtually all major manufacturers of large disk arrays), there are no disks visible to your computers. All the electronics and your SAN administrator's setup have 'virtualized' disk space. A specific data file may be spread across 5 or 10 or more disks, and the response time is buffered with a large internal cache that makes the data available much faster than for a single disk.
In the XP, there might be smaller disks which will be faster because there will be more disks for the same amount of data) and bigger disks which are cheaper but slower because a lot more data is contained on a single disk. These are called disk groups and will be referred to as high performance or archive (slower performance). You SAN admin can tell you about the groups that have been setup.
