利用者:HollifieldGreenlee743
Laptop hard disk drives are smaller variants of the larger desktop counterparts and generally emphasize power efficiency more than raw capacity of groundbreaking performance. You will find fair numerous major industry stalwarts competing within the cutthroat laptop hard disk business: Fujitsu, Hitachi, Samsung, Seagate, and Western Digital.
Past generations of laptop hard disk drives trusted parallel ATA interfaces which not just limited transfer bandwidth, but weren't as electrically efficient as the power sipping SATA and SATA 3.0 Gpbs standards that saturate the current market. The interface is a key performance factor of laptop hard disk drives as it is a measure of the maximum quantity of data that may be transferred to and from the drive. While the interface standards for laptop hard disk drives has kept well in front of their sustained performance potential, it's not uncommon for that interface to be a limiting factor for transfer performance in quick bursts.
Another performance characteristic, often considered to be the primary factor influencing overall read/write speed in addition to access time may be the rotation velocity. Laptop hard disk drives have power and thermal constraints that limit their performance to spindles with speeds of 7200 rotations each minute (RPM) or less. The faster a given disk can rotate its magnetic platter(s), the faster it may write information as well as find and read stored data. Even at 7200 rpm, the performance of laptop hard drives doesn't measure up to that of similar capacity desktop units.
One of the leading reasons for this is actually the quantity of platters is restricted by the physical height of the drive. Magnetic platters that store data in any hard drive need a specific amount of space between them in order for a read/write head to move across them and create, change, or access information. Laptop hard drives are physically smaller, and therefore the quantity of platters is limited, but same with the performance per platter. Take any two spinning circles of various sizes and something will note that when rotating the same number of times within the same period, the outer edges from the larger circle will travel a larger total distance. In the world of laptop hard drives this means that the length a read/write covers at 7200 rpm is quantifiably under the length it might cover when the platter were physically larger.
The platters themselves also play an issue. The more densely packed the information, referred to as the aural density, the faster it can generally be read from and the quicker it can be written. This is not always true, as sometimes the technology for that read/write heads lags behinds and an rise in aural density results in slower seek times.
The ultimate performance related factor for laptop hard drives is the cache. The cache is really a small pool of volatile memory similar to system RAM that acts as a buffer for writes and frequently stores recently and/or frequently accessed information. The buffer is the primary reason why interface standards can limit bursting performance regardless of the lack of sustainable performance approaching theoretical limits of the interface specification.