| IDEA |
| SCANCOM |
| Juke Box management Software |
The Compact Disc is a high-density Read Only Memory and laser-encoded optical storage medium defined by the Yellow Book Standard to store computer data including applications, text, audio, video, and image files. A CD has a life span close to 100 years and may store 10,000 to 15,000 pages depending upon how they are scanned. The CD is used to store and archive historical data and also for transportation of data.
The data on a CD is stored in one track with a sector size of 2048 bytes, is permanent, and cannot be accidentally erased. Microscopic bumps that contain the data of a track are referred to as pits and the flat areas that separate the pits are called lands. ISO 9660 is the international standard for the CD file format. ISO 9660 Level 1 specifies the 8.3 convention for the filenames, and Level 2 allows longer filenames and deeper directory structures, up to 32 levels, instead of 8.
The CDs are the most widely accepted storage media to store text, audio, video, software etc., and particularly preferred for storage of data, which is low in volume and not accessed frequently. A large number of CDs can be managed with the CD Jukebox, which is a preferred choice in most of the libraries and research organizations.
The data on a CD is stored in one track with a sector size of 2048 bytes, is permanent, and cannot be accidentally erased. Microscopic bumps that contain the data of a track are referred to as pits and the flat areas that separate the pits are called lands. ISO 9660 is the international standard for the CD file format. ISO 9660 Level 1 specifies the 8.3 convention for the filenames, and Level 2 allows longer filenames and deeper directory structures, up to 32 levels, instead of 8.
The CDs are the most widely accepted storage media to store text, audio, video, software etc., and particularly preferred for storage of data, which is low in volume and not accessed frequently. A large number of CDs can be managed with the CD Jukebox, which is a preferred choice in most of the libraries and research organizations.
DVD (Digital Video or Versatile Disk)
It is the latest generation of optical disk storage medium that is used to store large volume of audio, video, and data of very high quality. It can store data up to 4.7 Gigabytes (single layer), 8.5 GB (double layer), 9.4 GB (double sided, single layer) or 17 GB (double sided, double layer).
Large Storage Devices
To handle the ever-increasing data, large storage devices are very handy and provide cost effective solutions with varied efficiencies, depending upon the requirements. Data is stored on CDs or DVDs, which are managed using devices like changers, towers and jukeboxes.
CD Changer
A CD changer is a device with a single CD drive and several CD slots (4 to 18). The user can access one CD at a time as the CDs are picked up from slots and placed in the CD drive by a mechanical robotic arm. These devices are quite efficient, reliable and are preferred when storage and access-time requirements are not too demanding. CD Changers with more than one drive are also available.
CD Tower
A CD tower is a stack of several CD ROM drives which can have up to 144 drives in multiples of seven, connected in a daisy chain. These devices are preferred when it is easy to connect to the system and the retrieval speed is critical. However, the solution is not very cost effective.
CD Juke Box
AA CD jukebox is similar to a CD changer and is also called Auto-changer. It is much larger than a CD changer and can handle up to 500 or even more CDs in a single enclosure. Multiple devices, each having up to four drives can be connected in a daisy chain to provide much larger storage capacities. These devices use the mechanism of caching, which helps in finding the directory details of a CD without mounting it and hence avoids the need to frequently swap the CDs from a slot to a drive and vice versa.
