These algorithms mandate the in-depth knowledge of disk internals, such as the number of cylinders, the number of sectors per cylinder, and the curve function of seek distance and seek time
, which are not usually accessible from the operating system's standpoint.
A disk cache of 256K is extremely important in lowering the average seek time
; a buffer of this size is not hard to find.
Slow Tape Seek Time
: Optical media and slow-loading tape drives, the solution typically chosen by most nearline storage users, provide access times that range from 10 seconds to more than 20 seconds, including 5 to 10 seconds for a robotic media exchange.
The new hard drive offers systems builders and storage vendors enterprise-class specifications: 1.2 million hours MTBF (Mean Time Between Failure) and 10,000 RPM, 5.2 milliseconds (ms) average seek time
Also, there are none of the delays associated with normal disk drives (seek time
, access time, etc.); when a database requests data from a file stored on solid-state disk, it is returned instantly.
The largest overhead in parity-based RAID systems for performance comes down to drive seek time
or the ability to access data from different locations of the platter.
These include, to name only a few: disk RPM, disk seek time
, disk data-rate, back-end bus data bandwidth, front-end bus data bandwidth, the number of front-end and back-end buses, cache size, protocol time, IOPS rate (for cache hits), as well as vendor unique and incomparable benchmark or stress testing results that are utterly incomparable to any other vendor's stress test results.
The technology uses only half the potential physical disk capacity order to speed disk arm movement (seek time
It enables the drives to oppose shock load levels without drive failure and they feature a sub-9.Oms average seek time
. Merging a 100MHz SDRAM memory for sustained transfer rate, it also offers a 2MB cache buffer, Maxtor's proprietary Dual Wave processor, and UltraDMA 66 for up to 66MB/sec transfer rates, adaptable to 100MB/sec rate with a utility installation.
The 5.25-inch MO drives feature rotational speeds of up to 3868rpm, using 2.6GB media, and have a maximum 20MB/sec data transfer rate and 25ms average seek time
These basic elements are seek time
, rotational speed, channel rate, and caching capability.