AIT |
"Advanced Intelligent Tape", a high-speed, high-capacity
magnetic tape data storage format developed and controlled
by Sony. Uses the helical scan method of reading and writing
to tapes. |
Areal Density |
Refers to the amount of data that can be stored in a given
amount of hard disk platter. Since disk platters surfaces are
two-dimensional, areal density is a measure of the number of
bits that can be stored in a unit of area. It is usually expressed
in bits per square inch (BPSI). Sometimes it is referred to as
bit density. Higher areas of density under the right
circumstances can improve the disks transfer rate. |
Auxiliary Storage/ External Storage/ Secondary Storage |
Data not directly accessible to the CPU, requiring the use of computers input/output channels. |
Bit |
A binary digit, taking the value of either a zero or a one. It is the
smallest amount of information in a binary digital system. |
Byte |
A unit of measurement of information storage, most often
consisting of eight bits. Eight bits of information can represent
256 different states. In many computer architectures it is a unit of
memory addressing. |
DAFS |
"Direct Access File System" is a network file system similar to
NFS and CIFS that allows applications to transfer data while
bypassing operating system control, network protocol and
buffering operations that can bottleneck throughput thus
degrading performance. |
DAS |
“Direct Attached Storage” a digital storage system directly
attached to a server or workstation without a storage network in
between. Mainly used to differentiate non-networked storage
from SAN and NAS. |
DLT |
"Digital Linear Tape" technology is a magnetic tape data storage
technology. DLT uses linear serpentine recording with multiple
tracks on half-inch wide tape. |
Exabyte |
A unit of storage equal to 1 quintillion bytes or 1 billion
Gigabytes. |
FC |
"Fibre Channel" is a gigabit-speed network technology primarily
used for connecting mass storage devices and tape libraries to
computer systems. |
GBIC |
An acronym for "Gigabit Interface Converter". A GBIC is a
standard for transceivers commonly used with Gigabit Ethernet
and Fibre Channel. By offering a standard, hot swappable
electrical interface, one gigabit ethernet port can support a wide
range of physical media from copper to long-wave single-mode
optical fiber at lengths of hundreds of kilometers. |
Gigabyte |
A unit of information or computer storage equal to 1,024
Megabytes. Abbreviated GB, not to be confused with Gb, which
is used for gigabits. |
HBA |
"Host Bus Adapter", connects a host system (the computer) to
other network and storage devices. |
Hot Plug/Hot Swap |
The ability to install or remove components of a computer, while
it is operating. |
iSCSI |
Small Computer System Interface protocol over an IP network.
Unlike other network storage protocols, such as Fibre Channel
which is the foundation of most SANs, it requires only the
simple and ubiquitous ethernet interface, or any other TCP/IPcapable
network to operate. This enables low-cost centralization
of storage without the expense normally associated with Fibre
Channel storage area networks. |
JBOD |
"Just a Bunch OF Disks", used to refer to hard disks that aren't
configured according to RAID. |
Kilobyte |
A unit of information or computer storage equal to 1,024 Bytes.
Abbreviated K, Kb, Kbyte, and kB. |
LTO |
"Linear Tape-Open", is a magnetic tape data storage technology
developed as an open alternative to the proprietary Digital Linear
Tape (DLT). Developed jointly by IBM, HP, and Seagate. |
Megabyte |
A unit of information or computer storage abbreviated as M or
MB, equal to 1,024 x 1,024 = 1,048,576 bytes. Not to be
confused with Mb which is used for Megabit. |
Mirror Site |
A Mirror Site is an exact copy of another Internet site or set of
files on a computer system. Mirror sites are most commonly
used to provide multiple sources of the same information and are
of particular value as a way of providing reliable access to large
downloads. A mirror site will also will ensure better availability
and can increase performance. Mirroring is a type of file
synchronization. |
NAS |
"Network Attached Storage", is a file-level data storage
connected to a computer network providing data access to
heterogeneous network clients. NAS uses file-based protocols
providing both storage and file system storage. |
Nibble |
A 4 Bit aggregation - or half an octet. |
Petabyte |
A unit information or computer storage equal to 1,024 Terabytes,
or just over a million Gigabytes. Abbreviated as PB. |
RAID |
"Redundant Array of Independent Drives", originally known as
Redundant Array of Inexpensive Drives, RAID is an umbrella
term for data storage schemes that divide and/or replicate data
among multiple hard drives. RAID can be designed to provide
increased reliability and/or increased I/O performance. |
SAN |
"Storage Area Network" is architecture that attaches remote
computer storage devices such as disk arrays, tape libraries and
optical jukeboxes to servers in such a way that, to the operating
system the devices appear as locally attached devices. |
SCSI |
An acronym for "Small Computer System Interface". A set of
standards for physically connecting and transferring data
between computers and peripheral devices. The SCSI command
architecture was originally defined for parallel SCSI buses but
has been carried forward with minimal change for use with
iSCSI and serial SCSI. Pronounced "skuzzy". |
SDLT/SuperDLT |
"Super Digital Linear Tape" technology, a variant with higher
capacity can store from 110 GB to 300GB on a single cartridge
and can transfer data at speeds of up to 10 megabytes per second.
SDLT adds an optical servo system that reads servo patterns on
the back of the tape in order to keep the data tracks on the front
of the tape correctly aligned with the read/write heads. |
NIA |
"Storage Networking Industry Association" is an association of
producers and consumers of storage networking products, whose
goal is to further storage networking technology and
applications. SNIA was incorporated in December 1997 whose
members are dedicated to "ensuring that storage networks
become complete and trusted solutions across the IT
community." |
Storage Consolidation |
"Storage Consolidation" is a method of centralizing data storage
among multiple servers. Also know as storage convergence. |
Terabyte |
A unit of information or computer storage equal to 1,024
Gigabytes. Abbreviated as T or TB, not to be confused with Tb,
which is a terabit. |
Storage Virtualization |
Physical storage resources are aggregated into storage pools,
from which the logical storage is created. Multiple independent
storage devices which may be scattered over a network, appear
to the user as a single, location-independent, monolithic storage
device which can be managed centrally. |
WORM |
"Write Once Read Many" times is a type of computer storage
media that can be written to once, but read from multiple times.
There are two types of WORM storage media: those that
physically can be written only once, such as CD-R and DVD-R
and media that enables WORM capability by using electronic
keys or other measures to prevent rewriting. |
