Clustering
Disk-to-Disk Backup
Downward
Compatible
FireWire
Hot
Swap Benefit
RAID
Overview
RAID
Comparison
Repeater
Benefits
SAN
Overview
Termination
Basics
Interface
& Connector
Reference
SCSI
Connectors
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Storage Dictionary
- magnetic
disk
- A flexible
or hard-disk medium used to store data in the form of minute
local variations in magnetization of the disk surface.
- magnetic
tape
- Storage
medium that uses a thin plastic ribbon coated with an iron
oxide compound to record data with electrical pulses. Magnetic
tape is a sequential storage medium; the next block of data
is recorded after the last block. In order to locate a specific
block of data, you have to look through the whole tape to
find it.
- magneto-optic
- A high-density,
erasable recording method. Similar to magnetic disk and
tape recording, but the grains of iron oxide matter are
much smaller. A laser heats the grain, which makes it susceptible
to magnetic influence. The write head passes over the grain
while it is still susceptible. The data can then be read
by another laser, whose light is not hot enough to change
the grain's polarity.
- megabyte
- 1,048,576
bytes. Broadly, one million bytes, or one thousand kilobytes.
- MHz
- (1)
Megahertz is a million cycles per second. Used as a measurement
of data transfer rate.
- micron
- millionth
of a meter-a micrometer (im)
- mil
- A unit
of linear measure equaling a thousandth of an inch, or 0.0254
mm. For example, 5 mils is 0.005 inches.
- MM
- MicroMiniature.
- modem
- Short
for modulator-demodulator. Device that allows digital signals
to be transmitted and received over analog telephone lines.
- mouse
- Hand-driven
computer input and pointing device.
- MSB
- Most
Significant Byte or Bit.
- MTBF
- Mean
Time Between Failures. The average time a component works
with out failure.
- MTTR
- Mean
Time To Repair. The average time it takes to repair a component.
- multimedia
- Combining
more than one medium for dissemination of information, such
as being text, audio, graphics, animation and full motion
video all together. Requires large amounts of bandwidth
and processing power.
- multi-mode
- In
SCSI, an interface that can switch between S-E and LVD automatically.
- multimode
fiber
- An
optical waveguide which allows more than one mode (rays
of light) to be guided. Allows for up to 500 meter distance
between devices.
- N_Port
- A port
attached to a node for use with point-to-point or fabric
topology.
- NAS
- Network
Attached Storage.
- NCP
(Netware Communication Protocol)
- The
Novell Netware file serving protocol that competes with
NFS and CIFS..
- nibble
- Informal
term for half a byte; the first four (0,1,2,3) or last four
(4,5,6,7) bits of a byte, are the low nibble and high nibble
respectively.
- NL_Port
- A port
attached to a node for use in all three topologies.
- network
- An
arrangement of nodes and connecting branches. Also, a configuration
of data processing devices and software connected for information
exchange.
- NFS
(Network File System)
- Open
standard for file sharing. Provides remote file system with
access semantics across a network (local or wide).
- node
- A device
that has at least one N_Port or NL_Port.
- OFC
- Open
Fibre Control. A safety interlock system that controls the
optical power level of an open optical fiber cable.
- offline
- Not
controlled by a system, nor communicating with it.
- online
- Controlled
by a system, or available to it.
- optical
disc
- A direct
access storage device that is written and read by laser
light. Certain optical discs are considered Write Once Read
Many, or WORM, because data is permanently engraved in the
disc's surface, either by gouging pits (ablation), or by
causing the non-image area to bubble, reflecting light away
from the reading head. Erasable optical drives use technologies
such as the magneto-optic technique, which electrically
alters the bias of grains of material after they have been
heated by a laser. Compact discs (CDs) and laser or video
discs are optical discs. Their storage capacities are far
greater than those for magnetic media.
- optical
fiber
- Any
filament of fiber, made of dielectric material, that guides
light.
- optical
scanner
- Input
device that translates human-readable or microform images
to bit-mapped or rastered machine-readable data.
- originator
- The
logical function associated with an N_Port responsible for
originating an exchange.
- outbound
fiber
- One
fiber in a link that carries information away from a port.
- output
device
- Any
device by which a computer transforms its information to
the "outside world." In general, an output device is a machine
that translates machine-readable data into human readable
information. Examples: video screens, printers, microform
devices.
- overhead
- In
data communications, it is the transmitted data which is
not part of the information sent. Overhead deals with control,
addressing, and error checking.
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