Development status
Each hard disk manufacturer strives to increase the internal transmission rate of the hard disk. In addition to improving signal processing technology and increasing speed, the most important thing is to continuously increase the capacity of a single disk to improve linearity. Density. As the linear density of a hard disk with a larger single disk capacity is higher, the seek frequency and movement distance of the head can be reduced accordingly, thereby reducing the average seek time and increasing the internal transmission rate. Although hard disk technology has developed rapidly, the internal data transfer rate is still at a relatively low (relatively) level. The low internal data transfer rate has become the biggest bottleneck of hard disk performance. For mainstream household-grade hard drives, the internal data transfer rate basically stays at around 600 MB/s, and this data will drop even lower during continuous work.
Difference
The unit of data transmission rate is generally MB/s or Mbit/s, especially the official data on internal data transmission rate uses Mbit/s as the unit. Here it is necessary to explain the difference between the two units:
MB/s means megabytes per second, Mbit/s means megabits per second, and the former means every The number of bytes transmitted per second, the latter refers to the number of bits transmitted per second. The letter B in MB/s is the meaning of Byte. Byte is the number of bytes, and bit is the number of bits. In the computer, every eight bits is a byte, that is, 1Byte=8bit, which is a 1:8 correspondence. Therefore 1MB/s is equal to 8Mbit/s. Therefore, when writing units, you must pay attention to the capitalization of the B letter. In particular, some people abbreviate Mbit/s as Mb/s. At this time, the size of the B letter can really be said to be a little miss, but it is a thousand miles away.
The above is the correspondence between MB/s and Mbit/s under normal circumstances, but in the data transfer rate of the hard disk, the two cannot use the general conversion relationship between MB and Mbit (1B=8bit) To perform the conversion. For example, the official nominal internal data transfer rate of a product is 683Mbit/s. At this time, you cannot simply think that 683 is divided by 8 to get 85.375, and 85MB/s is the internal data transfer rate of the hard disk. Because 683Mbit also contains many bits of auxiliary information, which is not exactly the data transmitted by the hard disk, simply using 8 to convert it will not be able to get the true internal data transfer rate value.