Survey data from companies that specialize in data recovery may be used to investigate the primary causes for how data actually gets lost.
Hard drive failure is the most common cause of data loss, accounting for 38 percent of data loss incidents.
Drive read instability includes occasions where media corruption or degradation prevents access to the data on a disk. This explains 30% of lost data.
Software corruption, which might include damages caused by system software or other program (e.g., a virus attack), accounts for 13 percent of data loss incidents.
User error accounts for 12…
Winchester Disk
Former code name for an early IBM hard disk model, sometimes still used to refer to the technology and design of most traditional hard drives.
Windows
Microsoft’s series of operating systems for personal computers. Currently popular versions are Windows 95 and Windows 98.
Word
Two bytes that are processed together in a single operation.
Workstation
A personal computer with exceptional capacity and performance capabilities for use mainly in engineering, design and audiovisual applications demanding immediate access to data and the ability to manipulate it in technically sophisticated ways.
Write
The recording of…
Virus Scanner
Software that is used to scan for and eradicate computer viruses, worms, and Trojan horses.
Viterbi Detection
An algorithm used in read channel technology that detects an entire sequence of data bits at a time and determines the most likely sequence of data bits by comparing actual sequence of data bit samples with sequences of possible data bit sample to accurately detect that data written to disk.
Voice Coil
An actuator motor; the force of the magnetic rotary voice coil produces a movement of the head that is proportionate to the force exerted by the…
Ultra SCSI
Provides 20 MB/s transfers over an 8-bit bus or 40 MB/s transfers over a 16-bit Wide SCSI bus. Also known as Fast-20 SCSI, this feature is most commonly found in SCSI-3 drives.
Ultra DMA/33
A high-speed host data transfer feature that transfers data at 33.3 MB per second.
Un-correctable Error
An error that cannot be overcome using Error Detection and Correction.
Unformatted Capacity
The total number of usable bytes on a disk, including the space that is required to record location, boundary definitions, and servo data. (See also formatted capacity.)
Universal Serial Bus (USB)…
TPI (Tracks per inch)
The number of tracks written within each inch of the disk’s surfaces, used to measure how closely the tracks are packed on a disk surface. Also known as track density.
Tagged Queuing
The ability of the drive to receive multiple I/O processes from each initiator.
Task File
The set of I/O Host Interface Registers used to transfer status, commands, and data between the host and the drive for the EIDE interface.
Thin Client Architecture
A computer system in which data is stored centrally, with only limited storage capacity at the various points…
SCA-2
SCA-2 (Single Connector Attach) interface incorporates a grounding contact, blindmate connector, direct plug misalignment tolerance, ESD protection, hot swap capability, and backplane connector options for SCSI devices. SCA-2 is commonly called the 80-pin SCSI connector.
SCSI Configure Automatically (SCAM)
Allows users to attach SCSI devices without worrying about configuration options.
SCSI-1
The Small Computer System Interface (ANSI document X3.131-1986).
SCSI-2
The Small Computer System Interface (ANSI document X3.131-1994).
SCSI-3
The ANSI X3T10 Working Documents (under development).
SCSI device
A host computer adapter, a peripheral controller, or an intelligent peripheral that can be attached…
RLL (Run Length Limited)
An encoding scheme used during write operations to facilitate data readback.
ROM (Read Only Memory)
Integrated circuit memory chip containing programs and data that the computer or host can read but cannot modify. The computer can read instructions out of ROM, but cannot store data in ROM.
RPM (Revolutions per Minute)
Rotational speed of the media (disk), also known as the spindle speed. Hard drives typically spin at one constant speed. The slower the RPM, the higher the mechanical latencies. Disk RPM is a critical component of hard drive performance because it directly…
