The rotational speed of an HDD is decided by a spindle motor. It is measured in RPM ( Revolutions per Minute). RPM is an important characteristic of an HDD and is reflected in its price. Generally, the higher the RPM is, the faster the read/write speed will be. Let’s take a closer look at the characteristics that could affect HDD performance.
1. Spindle Motor Rotational Speed
Spindle motor spins the drive up so that the read/write head could access the data stored on the platter. RPM is the measurement of how many revolutions the platter makes in a single minute. The rotational speed of the disks in the drives is the largest factor in the performance of the drive. Pricewise, RPM divides different HDDs into different categories.
2. Seek time
Seek time is the measure of how long it takes for the read/write head to travel to the track that contains data. It is often measured in millisecond.
3. Track-to-track time.
Track-to-track is the average amount of time the drive takes to move the read/write head to each sequential track on the drive. It is also measured in millisecond.
4. Full Stroke time
Full stroke is the amount of time it takes the drive head to move from the outer to the inner portion of the disk or the full length of the drive head's motion.
5. Amount of the buffer
A drive's buffer is an amount of RAM on the drive to store frequently accessed data from the drive. Since RAM is faster at transferring data than the drive head operation, it increases the speed of the drive. The more buffer on the drive, the more data that can be stored in the cache to decrease the amount of physical drive operation. Most drives today come with an 8MB drive buffer
6. Mean time between failures (MTBF)
MTBF of an HDD often indicates the average amount of time it takes for an HDD to experience its first error. Normally the amount should be over 30,000 hours. This is not a technical index and is often used by retailers to vaguely reflect reliability.
7. Maximum Internal data transfer rate
The rate of moving data between the disk surface and the controller on the drive. It is affected by data recording density and rotational speed of the disks.
8. External data transfer rate
The rate of reading data from controller to outer system.
9. Surface heat
Heat impacts the performance of the electronics within the computer, especially if there is poor ventilation.
These are some of the most important factors that can affect HDD performance. By gaining a better understanding of how HDD works we might as well be able to pick up early signs of a failing HDD, therefore, prevent potential data loss.
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