Traditionally content is moved down the storage hierarchy
as it ages, but in fact the most important piece of information in any organisation is the one needed for the next business evolution.
This is achieved by adding another logical layer to the storage hierarchy
, one that allows clients to access file blocks in the caches of other clients.
This classical representation of the data storage hierarchy
has recently undergone considerable modification as a result of our increasing reliance on the Internet and the flood of portable consumer appliances designed to communicate through it.
Key technologies included near-lossless, high-density image compression; high-speed imagery and data LANs; and a storage hierarchy
with the highest bits/|in.sup.3~ densities possible.
Integrated servers typically incorporate a storage hierarchy
made up of magnetic disks for online storage, tape or erasable optical disks for backup, and WORM (Write Once Read Many) optical disks for archiving.
Data Classification is a component of ILM and is used to assign a logical class (or tier) of storage in the storage hierarchy
to a data element.
Within a storage hierarchy
, CAS fits most naturally into the middle tier.