Quantum DLT 2000 Handbook page 98

as if it were a disk. Only a handful of companies provide this type
of software application, and it's typically used with desktop sys-
tems and not with servers or network access. DLTtape systems are
typically not used in this type of application. Most tape-as-disk
systems use lower end, inexpensive tape drives.
Hierarchical Storage Management (HSM)
Hierarchical storage management is a multi-level approach to pro-
viding access to little-used, but critical information (see Figure
9-2). An important fact to note here is that HSM is not a backup
system in the true sense. In fact, HSM presents a new set of chal-
lenges to IS managers.
HSM systems migrate little-used files to and from your server's
hard disk to lower cost storage media, usually tape. The data that is
migrated is still 100 percent accessible to the user, but recall speed
is slower. In many cases, HSM systems have solid state, hard disk or
RAM
Internal
Disk
Figure 9-2 Hierarchical Storage Management (HSM)
structured way to migrate aging files to increasingly less expensive
storage media and still provide rapid access.
HSM
Front-end
hard disks
Data
Directories
QUANTUM DLTtape HANDBOOK
DLTtape
libraries
(deep storage)
is a
9.5