Reprint knowledge of hard disk terminology _ hardware Maintenance

1, the speed of the hard disk rotationl Speed

That is, the spindle speed of the hard drive motor. Speed is one of the key factors determining the internal transmission rate of the hard disk, and it also affects the speed of the hard disk to a great extent. At the same time, speed is also a distinction between the hard drive grade one of the important signs. Currently the common hard drive in the market is generally 5400rpm (RPM) or 7200rpm, high-end SCSI hard drive can also reach 10000rpm or even 15000rpm. Theoretically, the faster the speed the better.

With the continuous increase of the hard disk capacity, the speed of the hard disk is also increasing. However, the increase of rotational speed also brings about a series of negative effects, such as increasing wear, increasing temperature and increasing noise. Thus, the liquid bearing motor (Fluid Dynamic bearing Motors) applied in the precision machinery industry was introduced into the hard disk technology to effectively absorb vibration, reduce wear and improve life.

2. Average seek time (Average)

The time it takes for a hard disk to move a read-write head to a specified track to find the appropriate target data, which describes the ability of the hard disk to read the data in milliseconds. When the capacity of the single disc is increased, the seeking action and the moving distance of the head are reduced, so that the average seek time is reduced and the hard disk speed is accelerated. At present, the average search time of the mainstream hard disk in the market is around 9ms generally.

3. Average latency (Average latency time)

Refers to the time when the head is moved to the track where the data is located, and then waits for the desired block of data to continue to rotate under the head, usually between the 2ms~6ms.

4. Average access times (Average access time)

The average time of the head to find the specified data, usually the sum of the average seek time and the average latency time. Average access time is most representative of the hard disk to find a data spent time, the shorter the average access time is better, generally between 11ms~18ms. Note: Now many hard disk ads in the average access time is said to be replaced by the average seek time.

5, burst data transmission rate (Burst data Transfer Rate)

Refers to the computer through the data bus from the internal buffer of the hard disk read the highest rate of data, also known as the external data transmission rate (External data Transfer Rate). This parameter should theoretically be equal to the speed of the interface, such as UDMA/66 hard disk should be 66mb/s, udma/100 hard disk should be 100mb/s. But in fact, due to the problem of interface efficiency, this value is often lower than the theoretical value of more than 10%.

6. Maximum internal data transfer rate (Internal data Transfer Rate)

    The maximum data transfer rate between the head and the hard disk cache, depending on the disk speed and the density of the disc data. At present, most of the internal transmission rate of hard drives around 40mb/s, but there are a few hard disk's maximum internal data transfer rate has exceeded 50mb/s, because the internal data transmission rate is the real bottleneck of the system, so we need to distinguish between these two concepts when buying. But generally speaking, the speed of the hard disk is the same, the single disc capacity of the internal transmission rate is high, in the single disc capacity of the same time, high speed of the internal transmission rate of hard disk.