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
Dictionary |
|
|
|
|
Storage Dictionary
- data
- According
to AT&T Bell Labs: data is "A representation of facts,
concepts, or instructions in a formalized manner, suitable
for communication, interpretation or processing."
- data
transfer rate
- The
rate at which the data moves across the I/O bus.
- decoding
- A process
to extract useful information from a string of bits.
- deserialization
- The
process of receiving information one bit at a time and reforming
it into a larger unit, such as a transmission character
or a byte.
- de-skewing
- The
adjustment made to a group of related signals to compensate
for various delays inherent in the system.
- destination
address
- A value
in the frame header of each frame that identifies the port
in a node that is to receive the frame.
- device
- A single
unit on the SCSI bus, identifiable by an unique SCSI address.
A SCSI device can act as an Initiator or as a Target.
- device
bus
- I/O
bus used to connect devices to a host bus adapter or controller.
- device
I/O driver
- A small
program that tells the computer's operating system how to
communicate with a particular type or peripheral device.
- differential
interface
- An
electronic signal configuration using a pair of lines for
transfer. On a SCSI bus "TRUE" is defined as SIGNAL, higher
differential configuration, compared to single-ended, is
in relative higher tolerance for common-mode noise, and
little crosstalk when used with twisted pair cables. There
are two variants: HVD (High Voltage Differential) and LVD
(Low Voltage Differential). HVD allows connections up to
25 meters; LVD up to 12 meters. The disadvantage of HVD
is the higher cost of components.
- digital
- Pertaining
to data that consists of digits. The use of binary code
to record information. "Information" can be text in binary
code like ASCII, or scanned images in a bit-mapped form,
or sound in a sampled digital form, etc. Recording information
digitally has many advantages over its analog counterpart,
mainly ease in manipulation and accuracy in transmission.
- disassembly
- A process
of dividing a source buffer into payloads for transmission
in frames.
- disconnect
- Action
that occurs when a SCSI Target releases control of the SCSI
bus, allowing the bus to go to the Bus Free phase.
- disk
- A round,
flat, magnetic or other medium with one or more layers deposited
on the surface where data can be recorded.
- disk
array/disc array
- Combining
redundant disk or disk drives for more capacity, speed,
or for disaster recover. Also see RAID.
- disk
drive
- A device
containing motors, electronics and other gadgetry for storing
(writing) and retrieving (reading) data on a disk. A hard
disk drive is one which is generally not removable from
the machine. A floppy disk drive accepts removable diskettes.
- disk
sector
- Magnetic
disks are typically divided into tracks, each which contains
a number of sectors. A sector, also called a block, typically
contains a fixed amount of data, such as 512 bytes.
- driver
- When
used in the context of electrical configuration, "driver"
is the circuitry that creates a signal on line. When used
in the context of software, "driver" is more often called
"device I/O driver".
- downward
compatibility
- A product
that is compatible with both current and earlier versions
of the product and technology. Browse to Downward
Compatibility for more information.
- dual-simplex
- A communication
protocol that permits simultaneous transmission in both
directions in a link, usually with no flow control.
|
|
