Jukebox management is the methodology by which an optical
jukebox (optical library) is presented as a file system
to a host server for the purpose of reading and writing
data files from and to optical media stored in the
library.
Because an optical jukebox is simply a hardware device
with no intelligence, by default it is unable to communicate
with a host file server and operating system. To establish
this communication, a third-party software application
is required. This application, referred to as Jukebox
Management Software, provides the functionality necessary
for tracking the media inventory in the jukebox, the
locations of data files on the media, the drive types
available (when utilizing mixed-media jukeboxes), and
the ability to transport media from a storage slot to
an available drive in order to service a read or write
request.
Many developers of jukebox management software support
a multitude of Operating Systems including Windows,
UNIX, Linux, and Novell, and can format the media
surfaces using native operating system formats or
a proprietary format. While some developers still
recommend their own proprietary format for various
reasons, many offer an additional option of formatting
media using the UDF (Universal Disk Format) file system.
UDF has recently become very popular, as it provides
the ability to interchange media with other jukebox
management software, regardless of server operating
system, provided they both read and write data to
the UDF specification. Other formats have their advantages
and disadvantages as well.
In addition to managing read and write requests,
jukebox management software also provides sophisticated
disk caching algorithms to enhance performance.
As files are written to an optical platter,
they remain in a hard disk cache so that subsequent
requests for those files are retrieved directly
from hard disk, eliminating the need to wait
for a robotic movement and load of an optical platter.
Once the allocated amount of cache becomes full,
the jukebox management software will intelligently
delete the older files from cache to make space
for new files. Likewise, as files are read back
from an optical platter, they are again cached
onto hard disk for subsequent reads. Aside from
improving performance for active data files,
using cache also extends the life of the optical library
by minimizing the number of disk swaps required
to retrieve data.
Due to the many complexities involved and the level
of expertise required to optimally configure jukebox
management software, it is highly recommended to consult
with a qualified optical jukebox integrator such as
Data Archive Corporation to assist with the configuration
of your storage solution, as well as provide a detailed
product overview to the administrator who will be
responsible for managing your optical jukebox. |
