Storage Media News & Update

Storage Media: Data Storage Device
As Defined in Wikipedia, the free encyclopedia

A data storage device is a device for recording (storing) information (data). Recording can be done using virtually any form of energy. A storage device may hold information, process information, or both. A device that only holds information is a recording medium. Devices that process information (data storage equipment) may either access a separate portable (removable) recording medium or a permanent component to store and retrieve information.

Electronic data storage is storage which requires electrical power to store and retrieve that data. Most storage devices that do not require visual optics to read data fall into this category. Electronic data may be stored in either an analog or digital signal format. This type of data is considered to be electronically encoded data, whether or not it is electronically stored. Most electronic data storage media (including some forms of computer storage) are considered permanent (non-volatile) storage, that is, the data will remain stored when power is removed from the device. In contrast, electronically stored information is considered volatile memory.

With the exception of barcodes and OCR data, electronic data storage is easier to revise and may be more cost effective than alternative methods due to smaller physical space requirements and the ease of replacing (rewriting) data on the same medium. However, the durability of methods such as printed data is still superior to that of most electronic storage media. The durability limitations may be overcome with the ease of duplicating (backing-up) electronic data.

Computer Storage:
Computer storage, computer memory, and often casually memory refer to computer components, devices and recording media that retain digital data used for computing for some interval of time. Computer storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers, and coupled with a central processing unit (CPU), implements the basic Von Neumann computer model used since the 1940s.

In contemporary usage, memory usually refers to a form of solid state storage known as random access memory (RAM) and sometimes other forms of fast but temporary storage. Similarly, storage more commonly refers to mass storage - optical discs, forms of magnetic storage like hard disks, and other types of storage which are slower than RAM, but of a more permanent nature. Historically, memory and storage were respectively called primary storage and secondary storage.

The contemporary distinctions are helpful, because they are also fundamental to the architecture of computers in general. As well, they reflect an important and significant technical difference between memory and mass storage devices, which has been blurred by the historical usage of the term storage. Nevertheless, this article uses the traditional nomenclature.

Technologies, Devices and Media:

Magnetic storage:
Magnetic storage uses different patterns of magnetization on a magnetically coated surface to store information. Magnetic storage is non-volatile. The information is accessed using one or more read/write heads. Since the read/write head only covers a part of the surface, magnetic storage is sequential access and must seek, cycle or both. In modern computers, the magnetic surface will take these forms:

* Magnetic disk
    o Floppy disk, used for off-line storage
    o Hard disk, used for secondary storage
* Magnetic tape data storage, used for tertiary and off-line storage

In early computers, magnetic storage was also used for primary storage in a form of magnetic drum, or core memory, core rope memory, thin film memory, twistor memory or bubble memory. Also unlike today, magnetic tape was often used for secondary storage.

Semiconductor Storage:
Semiconductor memory uses semiconductor-based integrated circuits to store information. A semiconductor memory chip may contain millions of tiny transistors or capacitors. Both volatile and non-volatile forms of semiconductor memory exist. In modern computers, primary storage almost exclusively consists of dynamic volatile semiconductor memory or dynamic random access memory. Since the turn of the century, a type of non-volatile semiconductor memory known as flash memory has steadily gained share as off-line storage for home computers. Non-volatile semiconductor memory is also used for secondary storage in various advanced electronic devices and specialized computers.

Optical Disc Storage:
Optical disc storage uses tiny pits etched on the surface of a circular disc to store information, and reads this information by illuminating the surface with a laser diode and observing the reflection. Optical disc storage is non-volatile and sequential access. The following forms are currently in common use:

* CD, CD-ROM, DVD: Read only storage, used for mass distribution of digital information (music, video, computer programs)
* CD-R, DVD-R, DVD+R: Write once storage, used for tertiary and off-line storage
* CD-RW, DVD-RW, DVD+RW, DVD-RAM: Slow write, fast read storage, used for tertiary and off-line storage
* Blu-ray (BD)
* HD DVD
* Ultra Density Optical (UDO)
* Professional Disc for DATA (PDD or ProDATA)

The following form have also been proposed:
* Holographic Versatile Disc (HVD)
* Phase-change Dual
* 3D optical data storage

Magneto-Optical Disc Storage:
Magneto-optical disc storage is optical disc storage where the magnetic state on a ferromagnetic surface stores information. The information is read optically and written by combining magnetic and optical methods. Magneto-optical disc storage is non-volatile, sequential access, slow write, fast read storage used for tertiary and off-line storage.

Ultra Density Optical Disc Storage:
Ultra Density Optical disc storage An Ultra Density Optical disc or UDO is a 5.25" ISO cartridge optical disc encased in a dust-proof caddy which can store up to 30 GB of data. Utilising a design based on a magneto-optical disc, but utilising phase change technology combined with a blue violet laser, a UDO disc can store substantially more data than a magneto-optical disc or MO, because of the shorter wavelength (405 nm) of the blue-violet laser employed. MOs use a 650-nm-wavelength red laser. Because its beam width is shorter when burning to a disc than a red-laser for MO, a blue-violet laser allows more information to be stored digitally in the same amount of space.

Current generations of UDO store up to 30 GB, but 60 GB and 120 GB versions of UDO are in development and are expected to arrive sometime in 2007 and beyond, though up to 500 GB has been speculated as a possibility for UDO.

Optical Jukebox Storage:
Optical jukebox storage is a robotic storage device that utilizes optical disk device and can automatically load and unload optical disks and provide terabytes of near-line information. The devices are often called optical disk libraries, robotic drives, or autochangers. Jukebox devices may have up to 1,000 slots for disks, and usually have a picking device that traverses the slots and drives. The arrangement of the slots and picking devices affects performance, depending on the space between a disk and the picking device. Seek times and transfer rates vary depending upon the optical technology. Jukeboxes are used in high-capacity archive storage environments such as imaging, medical, and video. HSM is a strategy that moves little-used or unused files from fast magnetic storage to optical jukebox devices in a process called migration. If the files are needed, they are migrated back to magnetic disk.

Other Proposed Methods:
Phase-change memory uses different mechanical phases of phase change material to store information, and reads the information by observing the varying electric resistance of the material. Phase-change memory would be non-volatile, random access read/write storage, and might be used for primary, secondary and off-line storage.

Holographic storage stores information optically inside crystals or photopolymers. Holographic storage can utilize the whole volume of the storage medium, unlike optical disc storage which is limited to a small number of surface layers. Holographic storage would be non-volatile, sequential access, and either write once or read/write storage. It might be used for secondary and off-line storage.

Molecular memory stores information in polymers that can store electric charge. Molecular memory might be especially suited for primary storage.

The above article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Data Storage Device" and .Wikipedia article "Computer Storage"

Industry Watch: Storage Media News
Welcome to XTVWorld.Com's Industry Watch Section's Storage Media News Pages..

Here you will get updated news headlines and news briefs from the world wide storage media industry. What's more - here you will also get to catch up with the latest video clips available on the same issue.

The topics covered in Industry Watch have been hand picked by our editors keeping XTVWorld.Com's technology savvy visitors in mind - and we hope you will find the topical news pages an useful tool for gathering regular information in the field of your industry.

The topic we have covered under "Storage Media" are:

• Magnetic Tape Data Storage
• DAT (Digital Audio Tape)
• UFD (USB Flash Drive)
• HDD (Hard Disk Drive)
• Memory Cards
• Optical Disc
• VTL (Virtual Tape Library)
• Database storage
• Tertiary storage
• NAS (Network-Attached Storage)
• SAN (Storage Area Network)
• Digital Video Tape:
• Processor Registers
• RAM
• Holographic Data Storage