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This article will explain in detail what kinds of hard drives there are in the computer. The editor thinks it is very practical, so I share it for you as a reference. I hope you can get something after reading this article.

The types of hard disk can be divided into: 1, solid state hard disk (SSD), using flash memory particles to store; 2, mechanical hard disk (HDD), using magnetic disk to store; 3, hybrid hard disk (HHD), is a kind of hard disk that integrates magnetic hard disk and flash memory.

The hard disk is one of the main storage media of the computer, which consists of one or more aluminum or glass discs. The disc is covered with ferromagnetic material.

I. types

Hard drives include solid state drives (SSD, new hard drives), mechanical hard drives (HDD traditional hard drives), and hybrid hard drives (HHD, a new hard disk based on traditional mechanical hard drives). SSD uses flash memory particles to store, HDD uses magnetic disk to store, hybrid hard disk (HHD: Hybrid Hard Disk) is a kind of hard disk that integrates magnetic hard disk and flash memory. The vast majority of hard drives are fixed and permanently sealed in the hard drive.

II. Capacity

As the data storage of computer system, capacity is the most important parameter of hard disk.

The capacity of a hard disk is measured in megabytes (MB/MiB), gigabytes (GB/GiB) or millions of megabytes (TB/TiB). The common conversion formula is: 1TBbytes 1024GB 1024MB and 1MB=1024KB. But hard disk manufacturers usually use GB, that is, 1G=1000MB, and Win systems still use the word "GB" to represent "GiB" units (1024 converted), so the capacity we see in BIOS or when formatting the hard drive will be smaller than the manufacturer's nominal value.

The capacity index of the hard disk also includes the single disk capacity of the hard disk. The so-called single disk capacity refers to the capacity of a single hard disk. The larger the single disk capacity is, the lower the unit cost is and the shorter the average access time is.

In general, the larger the capacity of the hard disk, the cheaper the price per byte, with a slight exception for hard drives that exceed the mainstream capacity.

When we bought the hard drive, it was said to be 500G, but the actual capacity was smaller than 500G. Because the manufacturer is converted according to 1MB=1000KB, so we buy a new hard drive, which is a little less than the actual consumption when we buy it.

Third, rotating speed

The rotational speed (Rotational Speed or Spindle speed) is the rotation speed of the motor spindle in the hard disk, that is, the maximum number of revolutions that the hard disk can complete in one minute. The speed of the speed is one of the important parameters to mark the grade of the hard disk, it is one of the key reasons to determine the internal transfer rate of the hard disk, and directly affects the speed of the hard disk to a great extent. The faster the speed of the hard disk, the faster the hard disk can find files, and the transmission speed of the relative hard disk will be improved. The speed of the hard disk is expressed in revolutions per minute, expressed in units as RPM,RPM, which is the abbreviation of Revolutions Per minute, which is rpm. The higher the RPM value, the faster the internal transfer rate, the shorter the access time, and the better the overall performance of the hard drive.

The spindle motor of the hard disk drives the disc to rotate at a high speed, resulting in buoyancy that makes the head float above the disc. To bring the sector to which you want to access the data under the head, the faster the speed, the shorter the waiting time. Therefore, the speed of the hard disk is largely determined by the rotational speed.

Household ordinary hard drives generally have 5400rpm and 7200rpm high-speed hard drives, which are also the first choice for desktop computer users, while for notebook users, they are mainly 4200rpm and 5400rpm. Although some companies have released 10000rpm notebook hard drives, they are still relatively rare in the market. Server users have the highest requirements for hard disk performance, the SCSI hard disk speed used in the server is basically 10000rpm, and even 15000rpm, the performance is much more than household products. The higher speed can shorten the average seek time and the actual read and write time of the hard disk, but with the continuous increase of the speed of the hard disk, it also brings some negative effects, such as the increase of temperature, the increase of motor spindle wear, the increase of working noise and so on.

IV. Manufacturers

1. Seagate

Founded in 1980, Seagate is now the world's number one manufacturer of hard drives, disks and read-write heads. Seagate is a global leader in planning, manufacturing and selling hard drives, providing products for enterprises, desktop computers, mobile devices and consumer electronics. 、

Merger and acquisition of Maxtor in 2005

From April to December 2011, it became the largest hard drive manufacturer after the acquisition of Samsung's hard drive business.

2. Western Digital (Western Digital)

Western Digital is a world-renowned hard disk manufacturer and now the second largest hard disk manufacturer in the world. Founded in 1979, it is headquartered in California, USA, and has branches or offices all over the world. It provides storage products for users on five continents and acquired Hitachi in March 2011.

Hitachi (HITACHI)

HITACHI Hitachi Group is one of the largest integrated multinational groups in the world, producing desktop hard drives and notebook hard drives. In 2002, it acquired the IBM hard disk manufacturing department. It was acquired by Western Digital in March 2011.

4. Toshiba (TOSHIBA)

Japan's largest semiconductor manufacturer and the second largest maker of integrated motors is owned by Mitsui Group. Mainly produces mobile storage products.

5. Samsung

The abbreviation of Samsung Group, the largest enterprise group in South Korea. The produced hard drives provide products for desktops, mobile devices and consumer electronics. On April 19, 2011, Seagate officially announced the acquisition of Samsung's hard drive business for $1.375 billion (cash and stock). On December 20, 2011, Seagate announced that it had completed the acquisition of Samsung Electronics Co., Ltd.'s hard disk business.

Types of interfaces

ATA

The full name of ATA is Advanced Technology Attachment, which connects the motherboard and the hard disk with the traditional 40-pin parallel data cable. The maximum speed of the external interface is 133MB/s, because the anti-interference of the parallel port is too poor, and the wiring takes up space, which is disadvantageous to the heat dissipation of the computer, so it will be gradually replaced by SATA.

IDE

The full name is Integrated Drive Electronics, that is, "electronic integrated driver", commonly known as PATA parallel port.

Advantages of RAID

1. The transmission rate is high. In partial RAID mode, many disk drives can transfer data at the same time, and these disk drives are logically a disk drive, so using RAID can achieve several times the speed of a single disk drive. Because the speed of the processor is growing rapidly, and the data transfer rate of the disk drive cannot be greatly increased, there needs to be a solution to solve the contradiction between the two. two。 Higher security. Compared with ordinary disk drives, many RAID modes provide a variety of data repair functions. When a disk drive in RAID has a serious problem and cannot be used, the data in this drive can be recovered through other disk drives in RAID, but ordinary disk drives cannot. This is the second reason for using RAID.

SATA

In 2001, the Serial ATA committee composed of Intel, APT, Dell, IBM, Seagate and Maxtor formally established the Serial ATA 1.0. in 2002, although the related equipment of serial ATA has not been officially listed, the Serial ATA committee has established the Serial ATA 2.0specification. Serial ATA adopts serial connection mode, and serial ATA bus uses embedded clock signal, so it has stronger error correction ability. Compared with the past, the biggest difference is that it can check the transmission instructions (not just data) and correct automatically if errors are found.

SATA Ⅱ

SATA Ⅱ is developed on the basis of SATA by chip giant Intel Intel and hard disk giant Seagate Seagate. Its main feature is that the external transmission rate has further increased from SATA's 150MB/s to 300MB/s. In addition, it also includes a series of technical features, such as NCQ (Native Command Queuing, native command queue), port multiplexer (Port Multiplier), interlaced boot (Staggered Spin-up) and so on. But not all SATA hard drives can use NCQ technology. In addition to the hard disk itself to support NCQ, the SATA controller of the motherboard chipset is also required to support NCQ.

SATA Ⅲ

Officially known as "SATARevision3.0", it is a new version of the specification released by the Serial ATA International Organization (SATA-IO) in May 2009, mainly doubling the transmission speed to 6Gbps, while downwards compatible with the old version of the specification "SATARevision2.6" (now commonly known as SATA3Gbps), the interface and data lines remain unchanged. The SATA3.0 interface technical standard was put forward by Intel in the first half of 2007 and is headed by Knut Grimsrud, the technical director of Intel's storage product architecture planning department. Knut Grimsrud said that the transmission rate of SATA3.0 will be as fast as 6Gbps, which will double that of SATA2.0.

SCSI

The full name of SCSI is "Small Computer System Interface" (minicomputer system interface), which is completely different from IDE (ATA). IDE interface is the standard interface of ordinary PC, while SCSI is not specially planned for hard disk, it is a kind of high-speed data transmission technology widely used in minicomputer. SCSI interface has the advantages of wide range of use, multitasking, large bandwidth, low processor occupancy, and hot swapping, but the high price makes it difficult to be as popular as IDE hard disk, so SCSI hard disk is mainly used in medium-and high-end servers and high-end workstations.

Optical fiber channel

Fibre Channel is spelled Fibre Channel in English. Like the SCSI interface, fibre Channel was not originally planned and developed for hard disk interface technology, but was designed specifically for network systems. However, with the need for speed in storage systems, fibre Channel is slowly used in hard disk systems. Fibre Channel hard disk is developed to improve the speed and flexibility of multi-hard disk storage system, and its appearance greatly improves the communication speed of multi-hard disk system. The main characteristics of fibre Channel are: hot swappability, high-speed bandwidth, remote connection, a large number of connected devices and so on.

Fibre Channel is planned in a multi-hard disk system environment such as a server. it can meet the high data transmission rate requirements of high-end workstations, servers, mass storage subnetworks and peripherals for bi-directional and serial data communication through hubs, switches and point-to-point connections.

Classification of RAID

RAID 0, disk array with no redundancy and no parity. The data is distributed on each disk at the same time, there is no fault tolerance, and the read and write speed is the fastest in RAID, but because any disk failure will invalidate the entire RAID system, the safety factor is even lower than that of a single disk. It is generally used in occasions with low requirements for data security but high speed, such as large-scale games, graphics and image editing, and so on. This RAID mode requires at least two disks, while more disks provide more efficient data transfer.

SAS

SAS (Serial Attached SCSI), that is, serial connection SCSI, is a new generation of SCSI technology, which is the same as the popular Serial ATA (SATA) hard disk. It uses serial technology to obtain higher transmission speed. And improve the internal space by shortening the connection line and so on. SAS is a new interface developed after parallel SCSI interface. This interface is planned to improve the performance, availability and scalability of the storage system, and to provide compatibility with SATA hard drives.

VI. Maintenance and maintenance

1. Keep the computer working environment clean

The breathing hole of the hard disk with ultra-fine filter paper is connected with the outside world, and it can be used in the ordinary indoor environment without purification device. If the environment is dusty, it will be adsorbed to the surface of PCBA, the interior of the spindle motor and block the respiratory filter, so it must be dustproof. In addition, the wet environment and unstable voltage can lead to hard disk damage.

2. Form the habit of shutting down the phone correctly.

When the hard disk is working, the power supply is suddenly turned off, which may cause violent friction between the magnetic head and the disk and damage the hard disk, and it will also cause scratches on the hard disk because the magnetic head cannot be reset correctly. When shutting down, be sure to pay attention to whether the hard disk indicator on the panel is still flashing, only when the hard disk indicator stops flashing and the hard disk ends reading and writing.

3. Move the hard disk correctly and pay attention to shockproof

When moving the hard drive, it is best to wait for more than ten seconds before the hard drive is completely shut down. When the hard disk rotates at a high speed during boot, the gentle vibration may cause the disc to rub against the read-write head, resulting in the bad track of the disk or the damage of the read-write head. Therefore, in the boot state, do not move the hard disk or chassis, it is best to wait for more than ten seconds after the hard disk completely shut down and then move the host or restart the power supply, so as to avoid the damage to the hard disk caused by instant surge. In the hard disk installation, disassembly process should be more careful, hard disk movement, transportation is strictly forbidden to bump, it is best to use foam or sponge packaging protection, as far as possible to reduce vibration.

Note: the so-called "anti-collision ability" or "shock-proof system" of the hard disk manufacturer refers to the shock-proof and anti-collision ability of the hard disk in the non-boot state, rather than the boot state.

This is the end of the article on "what are the hard drives in the computer?". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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