Theory-45 :- DAT (Digital Audio Tape) ,WORM (write once, read many)

DAT (Digital Audio Tape) is a standard medium and technology for the digital recording of audio on tape at a

Professional level of quality. A DAT drive is a digital tape recorder with rotating heads similar to those found in a video deck. Most DAT drives can record at sample rates of 44.1 kHz, the CD audio standard, and 48 kHz. DAT has become the standard archiving technology in professional and semi‐professional recording environments for master recordings. Digital inputs and outputs on professional DAT decks allow the user to transfer recordings from the DAT tape to an audio workstation for precise editing. The compact size and low cost of the DAT medium makes it an excellent way to compile the recordings that are going to be used to create a CD master.

As an archiving medium, DAT is an alternative to consider along with

• Digital Data Storage (DDS1 through DDS3)
• Optical disc
• VHS tape

Acronym for digital audio tape, a type of magnetic tape that uses a scheme called helical scan to record data. A DAT cartridge is slightly larger than a credit card in width and height and contains a magnetic tape that can hold from 2 to 24 gigabytes of data. It can support data transfer rates of about 2 MBps. Like other types of tapes, DATs are sequential‐access media. The most common format for DAT cartridges is DDS (digital data storage).

 

What is WORM (write once, read many)?

WORM (Write Once, Read Many) storage had emerged in the late 1980s and was popular with large institutions for the archiving of high volume, sensitive data. When data is written to a WORM drive, physical marks are made on the media surface by a low-powered laser and since these marks are permanent, they cannot be erased.

In computer media, write once, read many, or WORM, is a data storage technology that allows data to be written to a storage medium a single time and prevents the data from being erased or modified. Data stored on a WORM-compliant device is considered immutable; authorized users can read the data as often as needed, but they cannot change it. Immutable storage plays a pivotal role in meeting data security and compliance requirements and protecting against ransom ware and other threats.

Storage media that support WORM storage are purposely non-re writable to prevent anyone from intentionally or accidentally erasing or modifying the data after it is initially stored. Because of this feature, government agencies and enterprises have long used WORM devices for archival purposes. Organizations subject to compliance rules find the technology useful. For example, the Securities and Exchange Commission requires brokers and dealers to retain their digital records on storage media that preserves the records in a non-re writable, non-erasable format.

Re writable, or erasable, optical disk drives followed, providing the same high capacities as those provided by WORM or CD-ROM devices. However, despite the significant improvements made by recent optical technologies, performance continued to lag that of hard disk devices. On the plus side optical drives offered several advantages. Their storage medium is rugged, easily transportable and immune from head crashes and the kind of data loss caused by adverse environmental factors.

 

The result is that the relative advantages of the two types of system make them complementary rather than competitive – optical drives offering security, magnetic drives real-time performance. The development of the CD/DVD technologies to include recordable and re-writable formats has had a dramatic impact in the removable storage arena and compatibility is an important and unique advantage of the resulting family of products. Today’s market is large enough to accommodate a number of different technologies offering a wide range of storage capacities.

The predominant are:

• magnetic disk
• magneto-optical
• phase-change

At time of writing, the resulting range of capacities can be categorized as follows:

• floppy replacements (100MB to 150MB)
• super-floppies (200MB to 300MB)
• hard disk complement (500MB to 1GB)
• removable hard disks (1GB plus)