Last November, I received an e–mail from my editor, Tom
Kenny saying “…We have a feature on network storage
systems that we’re trying to figger out (so) what we’d
like from you, if you agree, is a glossary of common storage
and network terms. An IT glossary for the uninitiated pro audio
folks. Whammy think? A whole column of pedants in a box.” So
began this month’s Bitstream, a bass ackwards version of
my usual offering.
Granted, I could never compete with the many excellent IT glossaries
out there on the web but, I’ve tried to gather the most
common TLAs, techie phrases and geek–speak
for your edification. For those who need a bit of a mental housecleaning,
this month
will either sweep away some cobwebs or increase the BBF by
several orders of magnitude!
Note that bold words have their own definitions
in this glossary…
Index
Part One
(this page) |
— |
1394 to DLT |
|
— |
Dolby Digital to HBA |
|
— |
HCA to ILEC |
|
— |
in–band
to metadata |
|
— |
microcontroller to perceptual subband/transform codec |
|
— |
peripheral
to SCSI |
| Part Seven |
— |
|
|
|
|
1394 —
See IEEE 1394
802.11 —
See IEEE 802.nx
AAC — Advanced Audio Codec
AAC is an, um, advanced version of the widely used MP3 perceptual
sub–band/transform codec with additional
tools to reduce the encoded data rate while simultaneously reducing
encoding
artifacts. Formally known as MPEG-2 AAC.
AAF — Advanced Authoring Format
An ad hoc standard promoted by a coalition of vendors, chiefly
Avid and Microsoft, along with developers and end users. AAF
is a wrapper file format.
abstraction layer —
Abstraction layers are virtual programming buffers or software
insulators between the inner details of some individual resource
and any external entity that may want to use that resource.
AC-3 — Audio Coded (version) 3
Known to consumers as Dolby Digital, AC-3 is Dolby Laboratories’ 3rd
generation of Perceptual Subband/Transform Codec.
AC-3 is one of the mandated audio formats for both DVD-Video
and ATSC Digital
TV.
AIT —
AIT or Advanced Intelligent Tape is a proprietary, midlevel,
8 mm, helical scan data tape standard from Sony that that pioneered
the feature of embedded memory in the cartridge.
AP — Access Point
An access point is a specially configured node on a wireless
network that bridges the WLAN and a wired LAN.
API — Application Programming Interface
In the world of software, APIs are structured abstraction
layers
between the gory details of an individual application, operating
system or hardware item and the world
outside that software or
hardware.
application —
Executable software that provides some useful
tool(s) or function(s). In ye olden days, applications were called “programs.”
ASF — Active Streaming Format
A proprietary streaming format developed by
Microsoft that provides streaming media services for the Windows
Media framework.
ASP — Application Service Provider
A commercial entity that sells Web services.
asset —
To a rich media geek, an asset is a file that
represents a valuable commodity or could be useful at some time
in the future. Digital
video or audio files are both considered assets. To an IT geek,
assets are hardware boxes that do cool things
asymmetrical —
Asymmetrical refers to different, unequal or unbalanced data
services, such as ADSL’s send/receive
data rate.
asynchronous —
Asynchronous transmission refer, among other things, to techniques
that do not require a common clock between communicating devices.
Since streams and files are self–clocking,
timing signals are derived from framing bits within the data stream.
ATM — Asynchronous Transfer Mode
A high speed, fixed packet data transport standard that interoperates
with the switched circuit telephony network. Although providing
valuable QoS features, ATM is being supplanted by less expensive,
IP–based standards that interoperate better
with LANs and
MANs.
availability —
Availability, as used by IT professionals, refers to the amount
of uptime. A product, system or service with
three nines or better uptime is referred to as “high availability.”
baseband —
Baseband means the lowest scale or simplest rate at which of
messaging occurs in a communications system.
bit rate —
Data rate refers to the “raw” or baseband data rate
over time at which some file or stream is being delivered. The
data rate plus metadata and framing overhead make up the bit
rate.
BBF — Bitstream boggle factor
The tendency for Bitstream reader’s eyes to roll back into
their heads as the dense geek–speak causes the reader to
fall into a deep sleep.
bridge, to bridge —
A bridge is a device, ether hardware or software, that “bridges” or
connects two networks of the same type or protocol.
carrier class —
A marketing term used to denote a ruggedly constructed, full
featured product suitable for high availability uses. “…this
equipment is carrier class, buddy!”
CLEC — Competitive Local Exchange Carrier
CLECs are the commercial entities created to compete with the
ILECs when the Baby Bells were broken up. Covad and OneEighty
Networks are two examples of CLECs.
codec — Encoder/Decoder
Codecs are a broad class of signal processing that first transforms
a signal from the original storage method into another so as
to improve the distribution in some way. After distribution,
the signal or, in our case, data, is transformed back into some
semblance of the original. DTV, POTS, MP3 are all household examples
of codecs.
coding, coding method —
Coding refers to transforming or changing the characteristics
of a signal to make it more suitable for some intended application.
This optimization is usually for transmission from one location
to another or for storage onto some medium which is different
from the original medium. Coding can improve fidelity, optimize
carrier bandwidth, increase essence carriage, improve security
or provide error detection and/or correction.
COFDM — Coded Orthogonal Frequency Division Multiplexing
COFDM is the modulation method chosen for our domestic DAB service,
some versions of ADSL, and DTV services in Europe and Australia.
COFDM is used to encoding or impose digital audio data onto an
analog carrier signal.
colocation —
Colocation refers to renting a designated space where a company’s
servers is situating, along with other company’s in the
same physical location. All machines share common HVAC and power.
For physical security, each company usually has a lockable wire
cage for their equipment.
DAB — Digital Audio Broadcast
DAB is the TLA for wireless digital radio services, also know
as IBOC/DAB. DAB is “terrestrial” radio in that it’s
local or location–based, as opposed to national digital
satellite “radio.” IBOC or in–band, on–channel
means that DAB shoehorns a digital stream into the existing AM
and FM analog services, maintaining backward compatibility. DAB
employs lossy codecs to reduce the transmitted data
rate.
DAM — Digital Asset Management
A catchall phrase that describes the process of managing digital “assets,” files
whose essence is deemed valuable by an organization. DAM usually
refers to audio, motion and still image files in particular.
data —
Data is fundamentally any information of interest but, these
days, the word data implies a binary (base 2 arithmetic), machine–readable
representation of information.
data center —
A data center is a physical structure, usually a stand–alone
building, that is designed to house a multiplicity of computers.
Data centers can be private, serving a single company or, more
commonly, a public “utility” serving a variety of
companies.
data rate —
Often conflated with bit rate, data rate refers to the actual
throughput or aggregate rate over time at which the essence is
being delivered.
DDS — Digital Data Storage
DDS is a proprietary, entry level performance, 8 mm data tape
standard originally based on the DAT or digital audio tape format.
DDS is close to the end of the product life cycle and is being
supplanted by more modern formats such as VXA.
Directory Services —
On a LAN or WAN, directory services provide an abstraction layer,
identifying network assets including users, resources and the
various policies assigned to each. The result is that resources
and users are accessible without possessing the details about
a particular resource or node. Directory services also abstract
network topologies and protocols.
Distributed —
For an IT nerd, distributed mean decentralized rather than concentrated
in one node, physical location or server.
DLT — Digital Linear Tape
DLT is a proprietary, midlevel, linear data tape standard originally
developed by Matsushita.
To be continued…
