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Array- Multiple disks that function as one
independent disk
ATA- "AT Attachment" which is a hard drive with
an integrated controller
Backup- the process of copying data from one
storage device to another for safeguarding purposes
Bios- Represents basic input/output system.
The BIOS controls many computer functions including hard
disk accessibility
Bit- Represents binary digit. A bit is
the smallest unit of information on a computer- it can
be a 0 or 1
Boot Record- Contains the loading information and
partition table for the disk
Bus- an internal device inside a computer which is
used to attach peripherals
Byte- Consists of 8 consecutive bits
Cache- A temporary storage area for frequently
used data
Capacity- The amount of data a hard disk is
capable of storing
Clean Room- An environmentally controlled room
used to repair hard drives and or
electrical components
Cluster- A group of sectors
Cold Swap- When the power must be turned off
before removing or adding a component to the system
Controller- A module that controls signals
between the host and peripheral device (ex: an adapter
card)
CRC- Represents Cyclic Redundancy Check. It
is a method of detecting errors during the transmission
of data
Disk Failure Detection- When the RAID controller
automatically detects SCSI drive failure
Disk Traveling- Occurs when drives are placed in
a different order than the original order
Drive Groups- A group of drives logically linked
together and acting as one unit
Duplexing- Mirroring across two RAID cards
ECC- "Error Correcting Code" which is generating
redundant information used to detect and correct data
errors
Embedded Servo- Uses gaps in the data tracks to
store signals for the read/write heads
External RAID Controller- A RAID controller which
functions externally
File Allocation Table- A structure that records data
blocks of files (also called FAT)
Firewire- Similar to USB, Firewire supports data
transfer rates of up to 800 Mbps
Firmware- Code which exists in the ROM area of a
hard disk
Fault Tolerance- The capability of the system to
continue functioning when one component fails
HDA- Also known as head disk assembly- it is the
mechanical apparatus of a disk drive
Head- An instrument that can read and write data
to a hard disk platter.
Head Actuator- A device which moves the
read/write arm across the surface of the platter
Head Crash- An incident occurring when the
read/write heads crash onto the surface of the platter
of a hard disk.
Host- Any system to which drives are attached and
used for input/output operations and the storage of data
Hot Spare- A drive (not belonging to the
system) that can be used by the controller to rebuild a
drive that is system critical
Hot Swap- Ability to replace a bad hard drive with a
good drive without interrupting the server processing
and activities
IDE- Integrated drive electronics (also called
"ATA")
Interface- A hardware or software protocol that
allows the hard disk and the computer to exchange
data (ex: SCSI or ATA)
Internal RAID Controller- A controller circuit
board on a server or typically on the bus of the
computer
JBOD- "Just a Bunch of Disks" which can appear to
be a RAID array but actually are not and function
independently
Jumper- A plastic plug used on the circuitry to
change the parameters of a hard disk
Kilobyte- Represents 1,024 bytes.
Landing Zone- An area specifically created as a
"parking" area for the hard disk heads when not in use.
Megabyte- Represents 1,024 kilobytes (or 1,048,576
bytes)
NTFS- The file system used by Windows
Parity- Used in RAID to spread bits
across each disk enabling the recreation of data in the
event of hard drive failure
Parity Check- The controller verifies the
integrity of the data on the system drive and corrects
any inconsistencies
Partitioning- The appearance of several "images"
whose capacity of each image totals that of the entire
array
Platter- A round magnetic device found in a hard
disk that stores data. A hard disk can contain one
or many platters.
RAID- "Redundant Array of Independent or
Inexpensive Disks"
RAID Data Recovery- To recover and
rebuild data from a failed RAID array
RPM- A measurement of the speed of the platters
in a hard disk
SAS- Represents "serial attached SCSI" which
allows for high speed data transfers
SATA- Represents "serial ATA" to replace older
technology such as PATA
SCSI- "Small Computer System Interface" which
allows different devices to be connected to a PC using a
SCSI card
Sector- The storage unit of a hard disk
consisting of 512 bytes
Spanning- The ability to configure multiple drive
packs allowing the volume to be larger than a single
drive
Spindle- A part of the hard disk on which the
platters rotate
Terabyte- Represents 1,099,511,627,776 bytes.
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