Acoustic Noise
The level of sound the drive produces while operating, the smaller the number,the better
Access
The level of sound the drive produces while operating, the smaller the number,the better
Access time
Access time measures the time lapsed between the access command and the point in time where the head is positioned to read or write a specific sector (address), measured in milliseconds (ms). (The access time for HDDs is a combination of seek time, controller overhead, and rotational latency, i.e. time taken for desired sector to rotate under head for access)
Actuator
The mechanism that moves the head(s) to the correct cylinder. It generally comprises of two parts; a rotary voice coil and head gimble assembly. The actuator arm houses the head at the tip of its arm
Address
Assigning certain areas of a disk to particular data
Areal Density
Bit density; Bits per Inch (BPI) x Tracks per Inch (TPI). This reflects how dense the data is stored on the media of the HDD
ATA-3
Fast ATA (E-IDE), PIO Mode 4, S.M.A.R.T., Simple password, more sophisticated power management
Atapi
ATA packet interface, a communications protocol which allows the electronic controllers for IDE hard disk drives to handle up to four devices, including CD-ROMs and tape drives and tape drive, Atapi devices plug into the IDE Interface
Ultra-ATA
Merge of ATA-3 and Atapi into one, Strong command overlap
Ultra-ATA
A new, even higher performance Ultra DMA (transfer rate of 66 MB/s)
AV
Audio Visual. AV drives denotes drivers modified to enhance transfer rate performance for specific applications
Average Latency
The average amount of time it takes for the drive to rotate to the correct address, so that the head can begin reading or writing in its desired location (is derived from the spindle speed)
AVI
Audio video interleaved. A standard system, form Microsoft, for integrating sound and vision for Windows into a single file for hard disk or CD-ROM
Average Seek Time
The average time for a head to seek the address, calculated over a large number of random seeks