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8/14/2019 Data Recovery Glossary - R.pdf
http://slidepdf.com/reader/full/data-recovery-glossary-rpdf 1/2
R ‐ Data Recovery Glossary
R&D‐Research
and
development.
Radial Path – The straight‐line path from the center of the disk to the outer edge of
the disk.
RAID (Redundant Arrays of Independent Disks) –It is an idea in storage subsystems
that can deliver enhanced protection against data loss and down‐time than
conventional disk drives. RAID refers to a drive architecture that is designed to
protect critical data through redundancy. In theory, conventional discs which made
up the RAID arrays can function for hundred or even thousands of years without
losing data because of disc failure. Other benefits of RAID include an improvement in
input/output performance, allowing users to fine‐tune drive systems to match the
needs of specific applications and making servicing quicker and simpler.
RAM –Random Access Memory (also see DRAM, SDRAM). It is a data storage device
that does not affect the speed of access as different locations are accessed. This is an
anti‐thesis to the magnetic tape or magnetic disk where data access is much quicker
sequentially because physical movement is required in non‐sequential location of
the storage medium rather than just electronic switching. RAM’s are usually built
from semi
‐conductor
integrated
circuits,
which
can
be
dynamic
(DRAM)
or
static
(SRAM).
Read Channel – Performs the data encoding and conversions the drive needs to write
computer generated information onto a magnetic medium and then read that
information with a high degree of accuracy.
Read Verify‐ A data accuracy check performed by having the disk read data to the
controller, which then checks for errors but does not pass the data on to the system.
Read/Write Head
‐See
Head.
Recoverable Error‐ By ECC recovery or by re‐reading the data, a read error that the
drive can correct
Registry‐ See System Registry
RLL (Run Length Limited) – An encoding scheme utilized during write operations to
assist data read back.
8/14/2019 Data Recovery Glossary - R.pdf
http://slidepdf.com/reader/full/data-recovery-glossary-rpdf 2/2
ROM (Read Only Memory) – Integrated circuit memory chip containing programs
and data that the computer or host cannot modify but only read.Instructions cannot
be stored in ROM but the computer can only read instructions out of ROM.
Rotational Latency‐ The amount of deferral in obtaining information from a disk due
to the rotation of the disk.The average rotational latency for a disk is 5.8 which is
rotating at 5200 RPM milliseconds. See also Mechanical Latency.
RPM (Revolutions per Minute) –Spindle Speed is another name for the rotational
speed of the media (disk). Hard drives typically spin at one constant speed.
Mechanical latencies are higher the slower the RPM becomes. Disk RPM directly
impacts the rotational latency which is why it is a critical component of hard disk
drive performance.
Dolphin Data
Lab
http://www.dolphindatalab.com/