"A comprehensive glossary of data management and storage terms which ARE updated and Enhanced regularly"
Advanced Intelligent Tape (AIT)
AIT is magnetic tape technology, similar in appearance to an 8mm Exabyte tape. The cartridges use a helical scan recording method and consist of an advanced metal evaporated tape, which provides greater density than other types of magnetic tape. AIT media also include a Memory-In-Cassette (MIC) feature, which stores tape status and indexing information. They have native capacities of 50GB (AIT-2), 100GB (AIT-3) and 200GB (AIT-4). Super AIT (SAIT) uses half-inch cartridges with native capacities of 500GB (SAIT-1) and 1TB (SAIT-2).
ANSI
Abbreviation for American National Standards Institute.
Archiving
The process of removing infrequently used data from the current network storage area and keeping it in a specifically designed area where it can be easily and quickly retrieved.
ASCII
American Standard Code for Information Interchange.
ASEG
Australian Society of Exploration Geophysicists.
AVI
Audio Visual Interleave File Format.
BIL
Band Interleave File Format.
Bit
Bit is short for binary digit and it is a single numeric character which can hold only one of two values: 0 or 1. A bit is the smallest unit of information on a computer.
Buffer
Part of RAM used for temporary storage of data that is waiting to be sent to a device; used to compensate for differences in the rate of flow of data between components of a computer system, interface or peripheral.
Byte
A byte is composed of 8 consecutive bits.
CGM
Concatenated Graphics Metafile.
Clean Room
A clean room is an area in which the air quality, temperature and humidity are highly regulated and monitored in order to protect sensitive equipment from contamination. The air in a clean room is repeatedly filtered to remove dust particles and other impurities that can damage the production of highly sensitive technologies.
The measure of the air quality of a clean room is described in Federal Standard 209. Clean rooms are rated as "Class 10,000," where there exists no more than 10,000 particles larger than 0.5 microns in any given cubic foot of air; "Class 1000," where there exists no more than 1000 particles; and "Class 100," where there exists no more than 100 particles. Hard disk drive fabrication requires a Class 100 clean room.
CLERP9
Refers to the Australian Government’s Corporate Law Economic Reform Program (Audit and Reform Disclosure) Act 2004, which amends the Corporations Act 2001. It was a Bill drafted to provide a mechanism for promoting transparency, accountability and shareholder rights.
Data Migration
Data migration is the movement of large volumes of backup or archive data held in one format to another more technologically advanced format.
Degaussing
To degauss a magnetic storage medium is to remove all data stored on it by demagnetising it. A degausser is a machine that is used for this purpose.
Demultiplexing
Demultiplexing is the process of separating two or more channels previously multiplexed. Also referred to as “Demuxing”.
DLIS
Digital Logging International Standard.
Differential Backup
Differential backup is a backup process where the only files that are backed up are the ones which have been changed since the last full backup. It is less time consuming and more efficient for restoration purposes however, a signigicant amount of redundant information is stored using this method.
Digital Linear Tape (DLT)
DLT is a magnetic data storage tape and drive system that uses half inch linear recording in a single hub cartridge. It uses a special compression method, known as Digital Lempel Ziv 1 (DLZ1), which enables the storage and retrieval of data at high speeds and in large volumes.
DropOut
Refers to the signal loss caused by a tape head clog, defect in the tape, debris, or other feature that causes an increase in the head-to-tape spacing. A dropout can also be caused by missing magnetic material, faulty head or bad signals and transfers via an interface.
ECW
Enhanced Compressed Wavelet.
End of Data (EOD)
EOD is an electronic or magnetic marker (or series of markers) which indicates that the data contained on a tape has reached its end. An EOD indicates that no further information is recorded past this point.
End of Partition (EOP)
EOP is an electronic or magnetic marker indicates where one of many possible logical volumes on a tape ends. An EOP marker would generally be followed by a Beginning of Partitition BOP on a tape with multiple partitions.
End of Tape (EOT)
EOT is a magnetic or electronic indicator which signals the end of tape/transmission.
EPS
Encapsulated Postscript.
Exabyte
Exabyte is the original in high capacity 8mm magnetic tape storage technology. It was introduced by the Exabyte Corporation in the late 1980’s and was widely recognised as a reliable format offering high speed read/write capabilities and native capacities of up to 14Gb.
File
A file is a collection of data or information which has a name and that is capable of being manipulated as an entity. Some examples of types of files are data files, text files and program files.
Full Backup
Full backup is the process of backing up your entire data store, regardless of whether or not that data has been changed since the previous backup was performed. It makes a complete copy of all your data however, it is time consuming and creates many redundant backup files.
GDF2
General Data Format (Version 2).
GEOTIFF
Geo-referenced Tagged Image File Format.
GIF
Graphics Interchange Format File type.
GML
Geography Markup Language International Standard.
GXF
Grid Exchange Format.
Header
A header is generally a record, file or block at the start of data that can contain information such as the tape name, date, time, recorded format, length etc. Not all tapes have headers although most tapes created by backup software will tend to have one
Helical Scan
Helical scan is a method of recording data onto a slow moving magnetic tape and uses a rapidly rotating read/write head. The data is recorded onto diagonal tracks, which are at an angle to the edge of the tape. After loading into a drive, the tape is pulled from the cartridge and wrapped around the read/write head, which rotates at around 30 metres per second. To view video of a helical scan loading, please click here.
High Voltage Differential
HVD SCSI interface predominantly associated with large scale enterprise tape drives. Power consumption is 5.0Volts and over.
Holographic Data Storage
Holographic data storage allows users to store an entire page of data at once, as an optical interference pattern within a thick, photosensitive optical material. This is done through the use of an argon laser beam that is split into two beams – the signal/object beam and the reference beam. The signal beam travels straight and bounces off a mirror, after which it travels through a spatial light modulator (SLM). The SLM is a liquid crystal display (LCD) that shows pages of raw binary data as clear and dark boxes. This information is then carried by the signal beam around to the light-sensitive lithium-niobate crystal or photopolymer. The reference beam shoots out the side of the beam splitter and takes a separate path to the crystal. The interference pattern that is created when the two beams meet stores the data carried by the signal beam in a specific area in the crystal – the data is stored as a hologram.
Incremental Backup
Incremental backup is the process of only backing up the files which have changed since the last backup of any type. The process itself is quicker, however, if the server crashes it takes significantly longer to reinstall and find files.
Interface
A term used for a descriptive common boundary between peripheral and computer system, can also be a piece of software to interact with to control such peripherals or computer system.
JPG, JPEG
Joint Photographic Experts Group.
Local Area Network (LAN)
A LAN is a data communication system whereby a group of computers and peripheral devices are linked together within a confined geographic area and are set up to share a common environment. Ethernet, FDDI and now wireless technologies are examples of standard LANs. A LAN may be used from two users upwards to many thousand.
LAS
Log ASCII Standard.
Leader Block
The beginning of nearly all high density tape has a 'leader' structure of some description. The 'block' is found on such cartridges as 34XX and 35XX cartridges to name a couple and is generally a plastic oblong shaped device which holds the beginning of the tape. It serves a purpose to feed tape in and out of the cartridge generally guided through a tape path.
LIS
Logging International Standard.
Longitudinal Recording (also called Linear)
Longitudinal recording is a method of recording data whereby tape is passed by a non-moving recording head. The tracks are recorded parallel to the tape edge. To view video of a linear or longitudinal scan loading, please click here.
Low Voltage Differential (LVD)
LVD SCSI Interface now predominantly found on SME tape drives, disk drives and equipment. Power consumption is around 3.3 Volt, most times less than 5 Volt.
Linear Tape Open (LTO)
LTO is an open format tape storage technology developed by Hewlett-Packard (HP), IBM, and Certance. The term "open-format" means that users have access to multiple sources of storage media products that will be compatible. The high capacity implementation of LTO technology is known as the LTO Ultrium format, or simply LTO Ultrium.
The LTO Ultrium technology has evolved through several generations.The latest of these is Generation 3, which became available in late 2004 and provides data storage capacity of up to 800 gigabytes (GB) and a maximum transfer rate of 80 to 160 megabytes per second (MB/s). Generations 4, 5, and 6 are currently under development. Generation 4 is planned to provide a maximum storage capacity of 1.6 terabytes (TB) and a transfer rate of up to 240 MB/s. Generation 5 is expected to have a maximum storage capacity of 3.2 TB and a transfer rate of up to 360 MB/s. Generation 6 is expected to have a maximum storage capacity of 6.4 TB and a transfer rate of up to 540 MB/s. (All of these capacity and transfer speed figures are based on 2:1 data compression).
Magnetic Media
Magnetic media refers to any form of data storage device (tape or disk) which uses a magnetic surface for storing information and data.
Magnetic Tape
Magnetic tape refers to plastic flexible tape coated on one side with ferromagnetic material which is used for storing information and data. It is a sequential storage medium and is generally used for data backup and archiving purposes. Magnetic tape originally took the form of open reels (such as 9 & 21 track tapes) but have been superseded by cartridges and cassettes of many sizes and shapes.
Mammoth
Mammoth is an integrated 8mm magnetic tape storage technology that uses advanced data management features such as advanced metal evaporated (AME) media to improve data recording performance. Mammoth tape drives are designed to be used in a continuous 24/7 environment.
Media Migration
Media migration is the movement of data from one type of storage media to another data storage medium. This is usually carried out due to the adoption of a more technologically advanced data storage and backup technology and usually means a reduction in storage space due to a higher density media than previously used.
MPEG
Moving Pictures Export Group.
NAS –Network Attached Storage
A NAS is not to be confused with a SAN, main difference is that a NAS binds to an already existing LAN and is generally a'pool' of storage mediums in one device. Some forms of NAS can be a JBOD (Just a Bunch of Disk), SCSI RAID array, tape subsystem or a straight disk pool confined in a single device. Once again a NAS can be accessed via any server, PC or peripheral on the LAN.
Native Capacity
Native capacity refers to the total storage volume available on a particular media type if data is written to it without any compression.
Optical Character Recognition (OCR)
OCR is software technology that scans and reads printed or written text (characters scanned as a graphic) and translates and converts the image to digital character codes and text which can then be processed by the computer, such as ASCII.
Optical Media
Optical media is a form of data storage that uses polycarbonate material to store digital information. The data is accessed and read using laser diode technology. Optical media generally comes in three forms - ROM (read only), WORM (write once read many), and RW (re-writeable).
P1/90
Navigation Data Standard Format.
PDF
Portable Data Format.
PET
Abbreviation for polyethylene terephthalate. This is the material used in the manufacture of most magnetic tapes.
Popped Strand
A popped strand is a strand of magnetic tape which protrudes from the edge of a wound tape reel.
POSC
Petrotechnical Open Software Consortium Organisation.
PPDM
Public Petroleum Data Model.
Quarter Inch Cartridge (QIC)
QIC is a magnetic tape technology that was developed in the 1980’s and used mainly for backup data storage purposes. There are two types – full size data cartridge and mini cartridge.
Redundant Array of Independent Disks (RAID)
RAID is a disk drive subsystem that uses two or more hard disks and a RAID disk controller in order to increase performance while at the same time provide fault tolerance. They are usually implemented in a server based environment using specialised software and/or hardware, however in more recent times desktop PCs are increasingly incorporating RAID disk systems with the addition of an onboard RAID controller and additional IDE, SATA or SCSI disks.
RAID can improve performance due to "Disk Striping", a process which allows multiple disks to read and write simultaneously. RAID systems can provide fault tolerance by processes called "Data Mirroring" and "Data Parity" – whereby data is entirely copied onto two drives and can be used to rebuild lost data when a drive fails.
There are a number of different RAID levels ranging from Level 0 – Level 10 and RAID subsystems come in various sizes from small desktop models to floor-standing models.
Sarbanes Oxley
Sarbanes Oxley is an Act that was passed by U.S. Government in 2002 to protect investors from the possibility of fraudulent activities by corporations. Its purpose is to improve the accuracy and reliability of corporate governance and covers issues such as financial disclosures and accounting as well as IT systems and the storage and retrieval of data.
The legislation was introduced to Congress as a result of a series of very high profile corporate scandals such as Enron, Tyco International and WorldCom. Also referred to as SOX.
Storage Area Network (SAN)
A SAN is a dedicated network of computer storage devices and servers which are connected at high speed. A SAN is structured in such a way that all storage devices (such as tape libraries and disk arrays) attached to the SAN are accessible from any server on the network and therefore provide consolidated storage management facilities.
Small Computer Systems Interface (SCSI)
SCSI is the general interface of choice for most tape and disk drives plus peripherals.
Super Digital Linear Tape (SDLT)
SDLT is magnetic tape drive technology that uses half inch linear recording in a single hub cartridge. It is a variant of DLT technology which was developed to increase (double) native and compressed cartridge capacity. Also see DLT.
SDTS
Spatial Data Transfer System.
SEG
Society of Exploration Geophysicists.
Serpentine Linear
Serpentine linear refers to a magnetic recording format whereby data is recorded in along the length of the tape in a linear fashion from one end of the tape to the other, and back.
SGML
Standard Generalised Markup Language.
Scalable Linear Recording (SLR)
SLR is a range of magnetic tape drive technology that evolved from QIC (Quarter Inch Cartridge) media technology.
Shoe Shining
The back and forth motion of a tape drive as it repositions between write sequences after it pauses it wait for data to be provided to it for writing.
SPS
Shell Processing System.
Stiction (Sticky Friction)
In the mid ’70s, it was found that a critical tape/head condition could occur in which the tape moving through a tape transport would physically stick to the tape head. The term applied to this condition was stiction (sticky friction). Stiction, as the term is used today, refers to a condition which produces similarly disastrous results but is caused by a quite different physical condition - namely the degradation of the binder layer of the tape itself. All binders absorb moisture but some appear to do so more than others. As this absorption occurs, chemical changes take place which tend to soften the binder. Expansion also occurs and this aggravates the problem by increasing the internal pressure within a reel of tape. As pressures build up, the softened components within the binder act as an adhesive which has the tendency to glue consecutive layers of the tape together.
Tape
Tape is a specialised strip of plastic, which has been magnetically coated to enable data to be encoded and recorded onto it.
Tape Baking
Tape baking is a data recovery process whereby a magnetic tape is heat treated for a brief period of time as a temporary cure for physically deteriorated tape suffering from "Stiction" or "Sticky Tape Syndrome". The process involves the application of dry heat in an oven type environment which allows the glue that holds the magnetic back coating of the tape to recombine and enable the tape to be read safely without the loss of data. This is a temporary measure and once moisture is reabsorbed the tape will no longer be able to be read.
Tape Drive
A tape drive is a computer peripheral that allows data to be read from and written to magnetic tape. Tape drives are frequently used for data backup and archiving purposes. Generally they are a sequential storage medium which means that they must read all data from beginning to end in order to read a specific piece of data.
TIF, TIFF
Tagged Image File Format File Type.
TMI
Total Magnetic Intensity.
TXT
Text.
UKOOA
United Kingdom Offshore Operators Association.
UTM
Universal Transverse Mercator.
VXA
VXA is a revolutionary 4mm tape drive technology which uses patented "packet" technology. This technology enables data to be read and written in packets - the same way that it is done on the internet. It is an extremely secure way to store, archive, retrieve, and exchange data and provides dramatically higher capacity and speed to other products at the same price level.
XML
Extensible Markup Language.
3590
3590 (Magstar) technology is a high capacity, high performance magnetic tape technology developed by IBM. It has gained wide acceptance and implantation in the marketplace by providing reliability and fast access to the midrange data centre/enterprise class and includes features such as Error Correction Code (ECC), servo track mechanisms, resident diagnostics, redundant parity checking, and read after write verification.
3592
3592 Jaguar tape technology offers significant improvements in speed, capacity and transfer rates to the enterprise level user over 3590. It provides both fast access to and retrieval of data as well as high capacity backup capability, a combination which was not available at the time of the 3592’s introduction. The 3592 tape drive also offers WORM (Write Once Ready Many) functionality.
9840
The 9840 tape media, based on the 3480 form-factor, provide fast access to data. They are a cost efficient option to disk for offline processing applications, providing higher data transfer rates for users to reduce batch windows and improve access to data. They have the ability to store up to 40GB of uncompressed data on a T9840C drive, and up to 20GB of uncompressed data on the T9840A and T9840B drives. They have an archival life of 15 to 30 years, with read and write specifics between 2.0m/sec and 3.4m/sec.