Manufacturer and dealers like to shower their clients with a lot of catchwords and accompanying data to show their products in the most favourable light. The following article reffers to the frequently used features of a Dell laptop hard drive.
The first characteristic of a hard drive is, of course, the storage capacity. A popular cheat is to indicate the unformatted capacity. As a user only the formatted data capacity is decisive for you, of course. Depending on the formatting parameters and the sector size, the formatted capacity may vary. In a Dell laptop, you can encounter hard drives having 500 GB or more. The laptops which use more than 500 GB are surely made for professionals.
Another popular quality, especially at the time of hard disk dinosaurs, is the acces time. But which one is meant? There are four different access times: track-track, positioning, random or full stroke. The first time indicates the time interval that the actuator requires to move the head from the current to an adjacent track.
The value includes the so-called settle time. When actuator and head are accelerated by the actuator motor and decelerated shortly before the destination track, they tend to oscillate. Once this oscillation has been dampened (that is, the head has settled), the head can access the track correctly.
The average positioning time indicates the time interval required on average to move the head from the current track to a randomly selected destination track. This time indication includes the head settle time, but not the so-called latency. When you attempt to access a certain sector of the Dell laptop hard disk drive by a controller command, then the drive must position the head above the intended track first.
Positioning time and latency together lead to the random or average access time. This is the time required for a random access to a certain sector, thus the average time for a completely random head movement from the current track to the destination, and the wait until the sector concerned appears below the head after the elapse of the latency time. Besides these access times, manufacturers often also indicate the full-stroke time. This is the time required to move the head from track 0 to the track with maximum cylinder number, or vice versa.
Another way of showing certain hard disks in a more favourable light by insufficient explanation is the data transfer rates. They generally refer to the quotient from the transferred amount of data and the time required for this. As a user of hard disks, the drive’s reliability is of particular importance. Where is the gain if you access data rapidly, but your drive is out of order because of a hardware failure? Manufacturers therefore generally indicate some reliability information.11