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Hard Drive Glossary
A
ATA (Advanced Technology Attachment)
A hard drive interface
standard for IDE (Integrated Drive
Electronics). A standard for storage devices that lets them be treated as if
they were hard drives on the system. Any ATA compatible media can be read by
any ATA device.
AVERAGE ACCESS TIME
The time (in milliseconds) that a hard drive takes to find
the right track in response to a request. plus the time it
takes to get to the right place on the track (the latency).
B
BACKUP
To make a copy of a file, group of files, or the entire contents of a hard
drive– either for archiving
purposes or for safeguarding valuable files from loss should the active copy
be damaged or destroyed.
BAD BLOCK
A disk sector that can no longer be
used for data storage, usually due to media damage or imperfections. .
BIOS (Basic Input/Output System)
A collection of computer routines that control peripherals such as hard
drives.
BIT
A binary digit: the smallest piece of information that can be recognized
and processed by a computer. A bit is either 0 or 1. Bits can form larger
units of information called bytes (8
bits).
BUNNY SUIT
A head-to-toe garment worn by personnel in a computer chip manufacturing
cleanroom.
BUS
A term used for an electronic device in which a number of elements are wired
together with a single wire in such way that all the elements can use the
same wire to transmit information to other devices on it. Buses are used
internally in computers and used to attach computers to peripheral
components. Only devices
addressed by the signals pay attention to them; the others discard the
signals.
BYTE
A sequence of adjacent binary digits that the computer considers a unit. A
byte consists of 8 bits.
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C
CACHE
High-speed Random Access Memory (RAM) used as a buffer between
the CPU and a hard drive. The cache retains
recently accessed information to speed up subsequent accesses to the same
data. When data is read from or written to disk, a copy is saved in the
cache along with the associated disk
address. The cache monitors the addresses of subsequent read operations to
see if the required data is already in the cache. If it is, the drive
returns the data immediately. If it is not in the cache, then it is fetched
from the disk and saved in the cache.
CAPACITY
The amount of data that a hard drive can store after the drive has been
formatted. Most hard drive companies
calculate disk capacity based on the assumption that –
1 megabyte = 1000 kilobytes
and
1 gigabyte=1000 megabytes.
CLUSTER
A hard drive term that refers to a
group of sectors, the smallest storage
unit recognized by DOS. On most modern hard disks, four 512-byte sectors
make up a cluster, and one or more clusters make up a track.
CONTROLLER
A device that transfers information between the computer and peripheral
component devices. The
controller (or "control unit") acts as a traffic manager.
CENTRAL PROCESSING UNIT (CPU)
The main processing chip of a computer. The CPU interprets and executes the
actual computing tasks, and has the ability to transfer information to and
from other resources over the computer's main data-transfer path, the bus.
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D
DATA RECOVERY
Data recovery is the procedure used to recover data
from a variety of media and operating systems that has been lost by either
hardware failure, human error, software bugs, a virus or a natural disaster.
DIRECTORY
A list of file names and locations of files on a hard drive.
DISK
A circular metal platter or with
magnetic material on both sides that stores data. Disks are rotated
continuously so that read/write heads mounted on movable or fixed arms can
read or write programs or data to and from the disk.
DISK CACHE
A portion of a computer's RAM set aside for
temporarily holding information that has been read from a disk. The disk cache does not hold entire
files as does a RAM disk, but information that has either been recently
requested from a disk or has previously been written to a disk.
DISK DRIVE
The motor that actually rotates the disk
plus the read/write heads and mechanisms.
DRIVE ARRAY
A storage system composed of several hard drives. Data is divided among the different drives for greater speed
and higher reliability.
E
EIDE
Enhanced IDE, also called Fast ATA or Fast IDE; a connection standard that's
faster than IDE and cheaper than SCSI.
F
FILE ALLOCATION TABLE (FAT)
The operating systems uses a file allocation table to keep track of which
clusters. are allocated to which
files and which are available for use.
FIBRE CHANNEL
A technology for transmitting data between computer devices at data rates
from 100 to 400 MBps over optical fiber or copper. Fibre Channel is
optimized for connecting servers to shared storage devices and for
interconnecting storage controllers and drives.
FIREWIRE
FireWire (also referred to as IEEE1394 High Performance Serial Bus) is a
very fast external bus that supports data transfer rates of up to 800 Mbps.
It is similar to USB. It preceded the
development of USB when it was originally created in 1995 by Apple. FireWire
devices can be connected and disconnected any time, even with the power on.
When a new FireWire device is connected to a computer, the operating system
automatically detects it and prompts for the driver disk.
FORMAT
A DOS command that records the physical organization of tracks and
sectors on a hard drive.
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G
H
HARD DISK
A mass storage device that transfers data between the computer's memory and
the disk storage media. Hard disks are rotating, rigid, magnetic storage
disks. (Also called hard drive.)
HEAD ACTUATOR
In a hard drive, the mechanism
that moves the read/write head radially across the surface of the platter of the disk drive.
I
IDE
Integrated Drive Electronics, also called ATA;
a connection standard that integrates the drive's controller chip on the drive
itself.
INTERFACE
The hard drive interface is the
"language" or protocol a drive uses to communicate with a host computer or
network. The three main types of drive interfaces are ATA/IDE, SCSI, and
Fibre Channell. The ATA
and SCSI interfaces have evolved to include many sub-types, which may or may
not be backwardly compatible.
I/O (Input/Output)
Input is the data flowing into your computer. Output is the data flowing
out. I/O can refer to the parallel and serial ports, keyboard, video
display, and hard drives and
floppy disks.
J
JUMPER
A plastic plug containing a metal bridge that completes a circuit; when
placed over different pins on a card, a jumper changes the parameters (for
example, forcing a hard drive
to be secondary storage rather than a boot disk).
K
KILOBYTE (KB)
1,024 bytes, but it is often used loosely
as a synonym for 1,000 bytes. Sometimes abbreviated as k (lowercase),
K-byte, K, or KB for kilobyte. Data transfer rates are measured in kilobytes
per second, abbreviated as KBps, and count a kilo as 1,000 bytes.
L
M
MTBF (Mean Time Between Failure)
A measure of reliability. The MTBF is the number of failures divided by the
number of hours the component has operated. The longer the time span between
failures, the more reliable the device.
MEGABYTE (MB)
1,048,576 bytes (1,024 times 1,024). Used
to describe the total capacity of a hard drive. Sometimes abbreviated as Mb, M, MB, or meg for megabyte.
MILLISECOND (ms)
1/1,000 (one-thousandth) of a second. Hard Drives are rated in
milliseconds. Higher numbers mean slower performance.
N
O
OPERATING SYSTEM (OS)
The operating system performs basic tasks such as recognizing input from the
keyboard, sending output to the screen, keeping track of files and
directories on the drive, and controlling
peripheral devices such as hard drives and printers. PC operating systems include DOS and Windows XP,
and Apple Macintosh operating systems include OS 9 and OS X.
P
PARTITIONING
A method for creating a logical file structure that the operating system can
access. Partitioning devides an area on the disk drive for use by more than
one disc operating system, or for dividing large disc drives into areas
which the file allocation table (FAT) can deal with when in use.
PERIPHERAL
A device that performs a function and is external to the system board.
Peripherals include displays, hard drives and printers.
PLATTER
A metal – or other rigid material – disk that is mounted inside a
fixed-disk drive. Many drives
consist of multiple platters mounted on the
spindle to provide more data storage
surfaces. Each platter may use one or both surfaces to store data.
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Q
R
RAID
(Redundant Array of Independent Disks)
A way of storing the same data in different places (thus, redundantly) on
multiple hard drives. By placing
data on multiple disks, input/output operations can overlap in a balanced
way, improving performance. Since multiple disks increases the mean time
between failure, storing data
redundantly increases fault-tolerance.
RAM (Random-Access Memory)
Also known as read-write memory; the memory used to execute application
programs.
ROM (Read-Only Memory)
The memory chip(s) that permanently store computer information and
instructions. Your computer's BIOS (basic
input/output system) information is stored in a ROM chip.
RPM
RPM is a measurement of how fast hard drive platters are
spinning (in revolutions per minute). The faster the spin rate, the less
time it takes for the drive to read or write a given amount of data.
RIBBON CABLE
A flat cable containing numerous wires, used to connect components within
the computer casing.
S
SCSI
(Small Computer System Interface)
A system-level interface designed for general purpose applications that
allows up to seven devices to be connected to a single host adapter. It uses
an 8-bit parallel connection that produces a maximum transfer rate of 5Mb
per second. The term is pronounced "scuzzy."
SECTOR
The basic storage unit on a hard drive.
On most modern hard disks, sectors are 512 bytes each, four sectors make up
a cluster.
SEEK TIME
Seek time is an average of how long a drive takes to move the read/write heads to a particular
track on the disc. It includes controller overhead but does
not include drive latency.
SMART (Self Monitoring Analysis And Reporting Technology)
SMART is an industry standard compatible with most modern hard drives and employs predictive diagnostics and
analysis to help foresee a drive failure before it happens.
SPINDLE
One part of a hard drive, around
which the platters rotate.
SYSTEM-LEVEL INTERFACE
A connection between the hard drive and its host
system that puts control and data-separation functions on the drive itself.
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T
TRACK
The circular path traced across the spinning surface of a disk platter by the read/write head inside
the hard drive. The track
consists of one or more clusters.
TRANSFER RATE
The speed at which a hard drive
can transfer information between its plattters and the CPU. The transfer rate
is typically measured in megabytes
per second, megabits per second, or megahertz.
U
ULTRA ATA/100
Ultra ATA/100 is an extension of the current Ultra ATA/66 interface. Ultra
ATA/100 is a high-speed interface that has the capability of a 100
Mbytes/sec transfer rate and a maximized disk performance under the current
PCI local bus environment.
UNIVERSAL SERIAL BUS (USB)
A serial bus with a bandwidth of 1.5 megabits
per second (Mbps) for connecting peripherals to a microcomputer. USB can
connect up to 127 peripherals, such as external CD-ROM drives, printers,
modems, mice, and keyboards, to the system through a single, general-purpose
port. This is accomplished by daisy chaining peripherals together. USB
supports hot plugging and multiple data streams.
UTILITIES PROGRAM
A program designed to perform maintenance work on a system or on system
components, e.g. a storage backup program, a disk and file recovery program,
or a resource editor.
V
VIRUS SCANNER
Software that is used to scan for and eradicate computer viruses, worms, and
Trojan horses.
VOLUME
A portion of a physical disk that functions
as though it were a physically separate disk.
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Glossary Information reprinted with permission
from Data-Recovery-Tools.net
Recommended site . Learn More Here
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