Several technologies exist today that help make optical discs on a LAN and WAN available.  There are many situations where an original CD or DVD is required for legal or security reasons.

The three types of technology are Direct attached DVD-ROM towers, Network Attached DVD-ROM towers, Disc Caching towers and robotic disc libraries or “jukeboxes”.

DVD-ROM towers are similar to a DVD duplication tower in form factor but instead of recorders (burners) the

CD Dimensions DVD-ROM tower

system is equipped with  readers.  DVD-ROM towers can be connected directly to a workstation or server via a SCSI connection and are considered “direct attached storage”.  The drives can be shared over a network but this is managed by the server or workstation the tower is attached to.  Another option are network attached DVD-ROM towers that have a built in Network controller which allows for browser access and configuration.  These tend to be faster in access then a direct attached over a network.

CD Dimensions CD DVD Disc Caching tower

DVD disc caching towers provide a means of storing a large number of ISO images on a built in hard drive (or RAID array for fault tolerance).  These images can be accessed across a network and appear as physical discs.  the primary advantage with caching systems is they are much faster then mechanical drives, store 10 times the amount of data and are far less expensive to purchase and maintain.  The only catch is copy protection (it can not be circumvented) and the data is cached on a hard drive.  Load time is very fast.

Disc Blu-ray Optical Disc Library

The last type of Disc library or better explained as ‘near line storage’ is the mechanical disc jukebox.  This is not to be confused with a music jukebox in the local pizza palace.  Jukeboxes store discs in cartridges or packs.   A mechanical arm moves up and down in the unit and picks the disc required and inserts it into an available drive for reading or writing depending on the application.  Jukeboxes can store from 100 to 1000 discs per unit (they resemble colorful refrigerators) and run in the range of $11,000 or more.  That does not include the special software required to “drive” the unit which runs another $9,000 plus yearly software maintenance. Optical disc library jukeboxes are designed primarily for archiving whereas DVD-ROM towers are designed specifically for data access.