硬盘(数据存储设备)

硬盘(英语:Hard DiskDrive,缩写:HDD,有时为了与固态硬盘相区分称“机械硬盘”或“传统硬盘”)是电脑上使用坚硬的旋转盘片为基础的非易失性存储器,它在平整的磁性表面存储和检索数字数据,数据通过离磁性表面很近的磁头由电磁流来改变极性的方式被写入到磁盘上,数据可以通过盘片被读取,原理是磁头经过盘片的上方时盘片本身的磁场导致读取线圈中电气信号改变。硬盘的读写是采用半随机存取的方式,可以以任意顺序读取硬盘中的资料,但读取不同位置的资料速度不相同。硬盘包括一至数片高速转动的盘片以及放在执行器悬臂上的磁头。

早期的硬盘存储介质是可替换的,不过现在硬盘的存储介质一般不能更换,盤片与磁头是一起被密封在硬盘驱动器内。硬盘有一个有着过滤措施的气孔,用来平衡工作时产生的热量导致的硬盘内外的气压差。

硬盘是由IBM在1956年开始使用,在1960年代初成为通用式电脑中主要的辅助存放设备(英语:secondary storage),随着技术的进步,硬盘也成为服务器及个人电脑的主要组件。

接口

数据接口

硬盘按数据接口不同,大致分为ATA(又称IDE)和SATA以及SCSI和SAS。接口速度不是实际硬盘数据传输的速度,目前普通硬盘的实际数据传输速度一般不超过300MB/s。

ATA

全称Advanced TechnologyAttachment,是用传统的40-pin并口数据线连接主板与硬盘的,接口速度最大为133MB/s,因为并口线的抗干扰性太差,且排线占用空间较大,不利电脑内部散热,已逐渐被SATA所取代。

SATA

全称SerialATA,也就是使用串口的ATA接口,特点是抗干扰性强,对数据线的要求比ATA低很多,且支持热插拔等功能。SATA-II的接口速度为300MiB/s,而新的SATA-III标准可达到600MiB/s的传输速度。SATA的数据线也比ATA的细得多,有利于机箱内的空气流通,整理线材也比较方便。

SCSI

全称Small Computer System Interface(小型机系统接口),经历多代的发展,从早期的SCSI-II,到目前的Ultra320SCSI以及Fiber-Channel(光纤通道),接口型式也多种多样。SCSI硬盘广为工作站级个人电脑以及服务器所使用,因此会使用较为先进的技术,如盤片转速15000rpm的高转速,且资料传输时CPU占用率较低,但是单价也比相同容量的ATA及SATA硬盘更加昂贵。

SAS

全称Serial AttachedSCSI,是新一代的SCSI技术,可兼容SATA硬盘,同样支持热插拔,采用序列式技术以获得更高的传输速度,可达到12Gb/s,盤片转速也较快。而较小的连接线,可改善系统内部空间空气流通。通常应用于服务器等企业级产品。此外,由于SAS硬盘可以与SATA硬盘共享同样的背板,因此在同一个SAS存储系统中,可以用SATA硬盘来取代部分昂贵的SAS硬盘,节省整体的存储成本。但SATA存储系统并不能连接SAS硬盘。

FC

全称FibreChannel(光纤通道接口),拥有此接口的硬盘在使用光纤联接时具有热插拔性、高速带宽(4Gb/s或10Gb/s)、远程连接等特点;内部传输速率也比普通硬盘更高。但其价格高昂,因此FC接口通常只用于高端服务器领域。

电源接口

3.5寸台式机硬盘:ATA接口的硬盘一般使用D形4针电源接口(俗称“大4pin”),由Molex公司设计并持有专利;SATA硬盘则使用SATA电源线。

2.5寸的笔记本电脑硬盘,可直接由数据口供电,不需要额外的电源接口。在插上外接的便携式硬盘盒之后,由计算机外部的USB接口提供电力来源,而单个USB接口供电约为4~5V500mA,若移动硬盘盒用电需求较高,有时需要接上两个USB接口才能使用,否则,需要外接电源供电。但如今多数新型硬盘盒(使用2.5寸或以下硬盘)已可方便地使用单个USB口供电。

结构

物理结构

硬盘的物理结构一般由磁头与盤片、电动机、主控芯片与排线等部件组成;当主电动机带动盤片旋转时,副电动机带动一组(磁头)到相对应的盤片上并确定读取正面还是反面的碟面,磁头悬浮在碟面上画出一个与盤片同心的圆形轨道(磁轨或称柱面),这时由磁头的磁感线圈感应碟面上的磁性与使用硬盘厂商指定的读取时间或数据间隔定位扇区,从而得到该扇区的数据内容;

  • 磁道

当磁盘旋转时,磁头若保持在一个位置上,则每个磁头都会在磁盘表面划出一个圆形轨迹,这些圆形轨迹就叫做磁道(Track)。

  • 柱面

在有多个盘片构成的盘组中,由不同盘片的面,但处于同一半径圆的多个磁道组成的一个圆柱面(Cylinder)。

  • 扇区

磁盘上的每个磁道被等分为若干个弧段,这些弧段便是硬盘的扇区(Sector)。硬盘的第一个扇区,叫做引导扇区。

避免故障

硬盘盤片转速极快,与盤片的距离极小;因此硬盘内部是无尘状态,硬盘有过滤器过滤进入硬盘的空气。为了避免磁头碰撞盤片,厂商设计出各种保护方法;目前硬盘对于地震有很好的防护力(1990年代的一些硬盘,若在使用中碰到略大的地震,就很可能损坏),防摔能力也大幅进步,电源关闭及遇到较大震动时磁头会立刻移到安全区(近期的硬盘也开始防范突然断电的情况);而许多笔记本电脑厂商也开发出各种笔记本电脑结构来加强硬盘的防摔性。但硬盘在通电时耐摔度会降低(旋转逆动性)、也只能温和的移动,许多人也已经养成在关闭硬盘后30秒至一分钟内、不会移动硬盘(及笔记本电脑)的习惯。

2010年后氦气封装技术量产,以往的硬盘填充介质为空气,不过容易受到空气影响,因此盤片之间距离要够才行,而氦气的密度比起空气小上许多,且氦气特色就是稳定,使用他来当介质,阻力和震动相对小,因此盤片之间的距离就能缩小,所以同样的空间下能够装下更多的盤片,采用氦气封装的好处除了容量变大外,温度和耗电能够再降低,因此耐用度和稳定性能够再提升。

逻辑结构

操作系统对硬盘进行读写时需要用到文件系统把硬盘的扇区组合成簇,并创建文件和树形目录制度,使操作系统对其访问和查找变得容易,这是因为操作系统直接对数目众多的扇区进行寻址会十分麻烦。

MBR和GPT

主引导记录(Master Boot Record,缩写:MBR),又叫做主引导扇区,是电脑引导后访问硬盘时所必须要读取的首个扇区,主引导扇区记录着硬盘本身的相关消息以及硬盘各个分割的大小及位置消息,是资料消息的重要入口。如果它受到破坏,硬盘上的基本数据结构消息将会丢失,需要用繁琐的方式试探性的重建数据结构消息后才可能重新访问原先的资料,对于那些扇区为512位组的磁盘,MBR分割表不支持容量大于2.2TB(2.2×1012字节)的分割。

全局唯一标识分区表(GUID Partition Table,缩写:GPT)是一个实体硬盘的分区表的结构布局的标准。它是可扩展固件接口(EFI)标准(被Intel用于替代个人计算机的BIOS)的一部分。GPT分配64bits给逻辑块地址,因而使得最大分区大小在264-1个扇区成为可能。对于每个扇区大小为512字节的磁盘,那意味着可以有9.4ZB(9.4 x 1021字节)或8 ZiB-512字节(9,444,732,965,739,290,426,880字节或18,446,744,073,709,551,615(264-1)个扇区x 512(29)字节每扇区)

尺寸

硬盘驱动器的尺寸和用途可分为:

  • 0.85英寸,多用于手机等便携设备中,目前已停产。
  • 1英寸(微型硬盘,MicroDrive),多用于数字相机(CF type II接口),目前已停产。
  • 1.8英寸,多用于笔记本电脑及外置硬盘盒中,目前已停产。
  • 2.5英寸,多用于笔记本电脑及外置硬盘盒中。采用2.5寸硬盘的外置硬盘盒一般不需外接电源。
  • 3.5英寸,多用于台式机中。但采用3.5"硬盘的外置硬盘盒一般都需外接电源,因为耗电量超过USB的供电上限,且3.5寸硬盘需要12v电压。
  • 5.25英寸,多为早期台式机使用,已停产。
  • 10.5英寸。
  • 14英寸,如NEC DKU800

主要参数

除了接口和尺寸以外,硬盘还有以下参数:

容量 硬盘最主要的参数,目前硬盘的容量有36GB、40GB、45GB、60GB、75GB、80GB、120GB、150GB、160GB、200GB、250GB、300GB、320GB、400GB、500GB、640GB、750GB、1TB、1.5TB、2TB、2.5TB、3TB、4TB、5TB、6TB、8TB、10TB、12TB、14TB、16TB、18TB等多种规格,但计算误差.。
转速 硬盘每分钟旋转的圈数,单位是rpm(Revolutions Per Minute,每分钟的转动数),有4200rpm、5400rpm、5900rpm、7200rpm、10000rpm、15000rpm、18000rpm等规格。一般来讲转速愈高通常资料传输速率愈好,但同时噪音、耗电量和发热量也越高。
缓存 主要有2MB、8MB、16MB、32MB、64MB、128MB、256MB等规格。
平均寻道时间 单位是ms(毫秒),有5.2ms、8.5ms、8.9ms、12ms等。
内部传输速度 包括磁头把数据从盘片读入缓存的速度,以及磁头把数据从缓存写入盘片的速度。可用来评价硬盘的读写速度和整体性能。

除此之外还有电压、电流等,固态硬盘还有主控、颗粒类型(SLC、MLC、TLC、QLC)等参数。机械硬盘里一般3.5寸硬盘需要5V和12V电压,2.5寸硬盘只需5V电压,但因为有机械结构,因此功耗通常比固态硬盘要高;固态硬盘的电压一般则为5V或3.3V,同时固态硬盘功耗通常较低(功耗2.5W左右,电流500mA左右),相比机械硬盘更节能。

发展史

时间 发展内容
1956年 IBM的IBM 305 RAMAC英语IBM 305 RAMAC是现代硬盘的雏形,它相当于两个冰箱的体积,不过其存储容量只有5MB。
1973年 这一年IBM 3340问世,它拥有“温彻斯特”这个绰号,来源于它的两个30MB存储单元,恰好是当时出名的“温彻斯特来福枪”的口径和填弹量。至此,硬盘的基本架构被确立。
1980年 两位前IBM员工创立的公司开发出5.25英寸参数的5MB硬盘ST506,这是首款面向台式机的产品,而该公司正是希捷科技公司(Seagate)。
1980年代末 IBM推出MR(Magneto Resistive磁阻)技术令磁头灵敏度大大提升,使盤片的存储密度较之前的20Mbpsi(bit/每平方英寸)提高数十倍,该技术为硬盘容量的巨大提升奠定基础。1991年,IBM应用该技术推出首款3.5英寸的1GB硬盘。
1970年到1991年 硬盘盤片的存储密度以每年25%~30%的速度增长;从1991年开始增长到60%~80%;至今,速度提升到100%甚至是200%。从1997年开始的惊人速度提升得益于IBM的GMR(Giant Magneto Resistive,巨磁阻)技术,它使磁头灵敏度进一步提升,进而提高存储密度。
1993年 康诺(Conner Peripherals)推出CP30344硬盘容量是340MB。
1995年 为了配合Intel的LX芯片组,昆腾与Intel携手发布UDMA 33接口——EIDE标准将原来接口数据传输率从16.6MB/s提升到33MB/s同年,希捷开发出液态轴承(FDB,Fluid Dynamic Bearing)电动机。所谓的FDB就是指将陀螺仪上的技术引进到硬盘生产中,用厚度相当于头发直径十分之一的油膜取代金属轴承,减轻硬盘噪音与发热量。
1996年 希捷收购康诺(Conner Peripherals)。
1998年2月 UDMA 66参数面世。
2000年10月 迈拓(Maxtor)收购昆腾。
2003年1月 日立宣布完成20.5亿美元的收购IBM硬盘事业部项目,并成立日立环球存储科技a>(Hitachi Global Storage Technologies, Hitachi GST)。
2005年 日立环储和希捷都宣布将开始大量采用磁盘垂直写入技术(perpendicular recording),该原理是将平行于盤片的磁场方向改变为垂直(90度),更充分地利用存储空间。
2005年12月21日 希捷宣布收购迈拓(Maxtor)。
2007年1月 日立环球存储科技宣布将会发售全球首只1Terabyte的硬盘,比原先的预定时间迟了一年多。硬盘的售价为399美元,平均每美分可以购得27.5MB硬盘空间。
2011年3月 西部数据以43亿美元的价格,收购日立环球存储科技。
2011年4月 希捷宣布与三星强化策略伙伴关系,传统的硬盘逐渐地被固态硬盘所取代。
2011年12月 希捷宣布收购三星旗下的硬盘业务。

现存主要硬盘制造商

  • 西部数据(Western Digital)和其子公司昱科环球存储 (HGST)
    • 日立环球存储科技:2011年被西部数据收购,并改名为昱科环球存储(HGST)。
      • IBM:2003年硬盘部门被 日立收购。
  • 希捷(Seagate)
    • 康诺(Conner):1996年被希捷收购。
    • 迈拓(Maxtor):2006年被希捷收购。
      • 昆腾(Quantum):2000年硬盘部门被迈拓收购。
    • 三星电子(Samsung):2013年硬盘业务被希捷收购。
  • 东芝(Toshiba)
    • 富士通(Fujitsu):2009年2月18日硬盘部门被东芝收购。

Hard Disk Drive

Hard Disk(English:Hard DiskDrive,abbreviation:HDD,sometimes called"mechanical hard disk"or"traditional hard disk"in order to distinguish it from solid-state hard drives)is a non-volatile memory based on hard rotating disks used on computers.It stores and stores on a flat magnetic surface.To retrieve digital data,the data is written to the disk through the magnetic head that is close to the magnetic surface and the polarity is changed by electromagnetic current.The data can be read through the disk.The principle is that the disk itself is when the head passes over the disk.The magnetic field causes the electrical signal in the reading coil to change.Hard disk reads and writes adopt a semi-random access method,which can read the data in the hard disk in any order,but the speed of reading data at different locations is different.The hard disk consists of one or several high-speed rotating disks and a magnetic head placed on the actuator cantilever.

Early hard disk storage media are replaceable,but now hard disk storage media generally cannot be replaced.The disc and the magnetic head are sealed together in the hard drive.The hard disk has an air hole with filtering measures to balance the pressure difference between the inside and outside of the hard disk caused by the heat generated during work.

The hard disk was used by IBM in 1956 and became the main auxiliary storage device(English:secondary storage)in general-purpose computers in the early 1960s.With the advancement of technology,hard disks have also become the main components of servers and personal computers..

Interface

Data interface

According to different data interfaces,hard disks are roughly divided into ATA(also known as IDE)and SATA,as well as SCSI and SAS.The interface speed is not the data transmission speed of the actual hard disk.At present,the actual data transmission speed of an ordinary hard disk generally does not exceed 300MB/s.

ATA

Full name Advanced TechnologyAttachment uses a traditional 40-pin parallel port data cable to connect the motherboard and the hard disk.The maximum interface speed is 133MB/s.Because the anti-interference of the parallel port cable is too poor,and the cable takes up a lot of space,it is not good for the internal heat dissipation of the computer.Gradually replaced by SATA.

SATA

The full name is SerialATA,that is,the ATA interface that uses the serial port.It is characterized by strong anti-interference,much lower requirements for data lines than ATA,and supports hot plugging and other functions.The interface speed of SATA-II is 300MiB/s,and the new SATA-III standard can reach a transfer speed of 600MiB/s.The data cable of SATA is also much thinner than that of ATA,which is conducive to the air circulation in the case,and it is more convenient to arrange the cables.

SCSI

Full name Small Computer System Interface(minicomputer system interface),has experienced multiple generations of development,from the early SCSI-II to the current Ultra320SCSI and Fiber-Channel(fiber channel),the interface types are also diverse.SCSI hard disks are widely used in workstation-class personal computers and servers.Therefore,more advanced technologies are used,such as high-speed disk rotation of 15000rpm,and lower CPU usage during data transmission,but the unit price is also higher than that of ATA and SATA of the same capacity.Hard drives are more expensive.

SAS

Full name Serial AttachedSCSI is a new generation of SCSI technology,compatible with SATA hard disks,and also supports hot-swappable.It adopts serial technology to obtain higher transmission speed,which can reach 12Gb/s,and the disk rotation speed is also faster.The smaller connecting line can improve the air circulation in the internal space of the system.Usually used in enterprise products such as servers.In addition,because SAS hard disks can share the same backplane with SATA hard disks,SATA hard disks can be used to replace some expensive SAS hard disks in the same SAS storage system,saving overall storage costs.However,SATA storage systems cannot connect to SAS hard drives.

FC

The full name is FibreChannel(Fibre Channel Interface).The hard disk with this interface has the characteristics of hot pluggability,high-speed bandwidth(4Gb/s or 10Gb/s),remote connection,etc.when using optical fiber connection;the internal transmission rate is also higher than ordinary The hard drive is higher.But its price is high,so FC interface is usually only used in high-end server field.

Power connector

3.5-inch desktop hard drives:ATA interface hard drives generally use a D-shaped 4-pin power interface(commonly known as"big 4pin"),designed and patented by Molex;SATA hard drives use SATA power cords.

The 2.5-inch laptop hard drive can be directly powered by the data port,without the need for an additional power interface.After the external portable hard disk box is plugged in,the external USB interface of the computer provides the power source,and a single USB interface power supply is about 4~5V500mA.If the mobile hard disk box has a high power demand,sometimes it is necessary to connect two USB interfaces.Use,otherwise,need an external power supply.But now most new hard disk enclosures(using 2.5-inch or smaller hard disks)can easily use a single USB port for power supply.

Structure

Physical Structure

The physical structure of a hard disk is generally composed of magnetic heads and disks,motors,main control chips,and cables;when the main motor drives the disks to rotate,the auxiliary motor drives a group(heads)to the corresponding disks and determines Read the front or back side of the disk.The magnetic head is suspended on the disk surface to draw a circular track(track or cylinder)concentric with the disk.At this time,the magnetic induction coil of the magnetic head senses the magnetic and magnetic properties on the disk surface.Use the read time or data interval specified by the hard disk manufacturer to locate the sector to obtain the data content of the sector;

  • Track

When the disk rotates,if the head is held in one position,each head will draw a circular track on the surface of the disk.These circular tracks are called tracks.

  • Cylinder surface

In a disc group composed of multiple discs,a cylindrical surface(Cylinder)composed of multiple tracks with different disc faces but in the same radius circle.

  • Sectors

Each track on the disk is equally divided into a number of arcs,and these arcs are the sectors of the hard disk.The first sector of the hard disk is called the boot sector.

Avoid trouble

The speed of the hard disk platters is extremely fast,and the distance from the platters is extremely small;therefore,the inside of the hard disk is dust-free,and the hard disk has a filter to filter the air entering the hard disk.In order to prevent the head from hitting the disc,manufacturers have devised various protection methods;at present,hard disks have good protection against earthquakes(some hard disks in the 1990s,if they encounter a slightly larger earthquake in use,they are likely to be damaged).The ability to fall has also been greatly improved.When the power is turned off and large vibrations are encountered,the heads will immediately move to the safe area(recent hard disks have also begun to prevent sudden power failures);and many notebook computer manufacturers have also developed various notebook computer structures.Strengthen the drop resistance of the hard disk.However,when the hard disk is powered on,its resistance to drop(rotational inversion)will be reduced,and it can only be moved gently.Many people have developed that they will not move the hard disk(and laptop)within 30 seconds to one minute after turning off the hard disk.habit.

After 2010,helium encapsulation technology was mass-produced.In the past,the filling medium of hard disks was air,but it was easily affected by air.Therefore,the distance between the platters must be sufficient.The density of helium is much smaller than that of air.The characteristic is stability.Using it as a medium,the resistance and vibration are relatively small,so the distance between the platters can be reduced,so more platters can be installed in the same space.The advantage of using helium packaging is that the capacity is changed.In addition,the temperature and power consumption can be further reduced,so the durability and stability can be further improved.

Logical Structure

When the operating system reads and writes to the hard disk,it needs to use the file system to combine the sectors of the hard disk into clusters,and create a file and tree directory system to make it easy for the operating system to access and find it because of the operation It would be very troublesome for the system to directly address a large number of sectors.

MBR and GPT

Master Boot Record Record(abbreviation:MBR),also known as the master boot sector,is the first sector that must be read when the computer is booted to access the hard disk.The master boot sector records information about the hard disk itself and the size and size of each partition of the hard disk.Location information is an important entry point for data information.If it is damaged,the basic data structure information on the hard disk will be lost.It is necessary to use a tedious way to tentatively reconstruct the data structure information before re-accessing the original data.For those disks with 512-bit sectors,MBR partitioning The table does not support partitions with a capacity greater than 2.2TB(2.2×1012 bytes).

Globally uniquely identify the partition table(GUID Partition Table(abbreviation:GPT)is a standard for the structure and layout of the partition table of a physical hard disk.It is part of the Extensible Firmware Interface(EFI)standard(used by Intel to replace the BIOS of personal computers).GPT allocates 64 bits to the logical block address,thus making it possible for the maximum partition size to be 264-1 sectors.For a disk with a sector size of 512 bytes,that means there can be 9.4ZB(9.4x 1021 bytes)or 8 ZiB-512 bytes(9,444,732,965,739,290,426,880 bytes or 18,446,744,073,709,551,615(264-1)sectors x 512(29)bytes per sector)

Size

The size and purpose of hard drives can be divided into:

  • 0.85 inches,mostly used in portable devices such as mobile phones,and has been discontinued.
  • 1 inch(micro hard drive,MicroDrive),mostly used in digital cameras(CF type II interface),currently has been discontinued.
  • 1.8 inches,mostly used in notebook computers and external hard disk enclosures,it is currently discontinued.
  • 2.5 inches,mostly used in notebook computers and external hard drive enclosures.External hard disk enclosures with 2.5-inch hard disks generally do not require an external power supply.
  • 3.5 inches,mostly used in desktop computers.However,external hard disk enclosures with 3.5" hard disks generally require an external power supply, because the power consumption exceeds the upper limit of USB power supply, and the 3.5-inch hard disk requires 12v voltage.
  • 5.25 inches, mostly used by early desktop computers, has been discontinued.
  • 10.5 inches.
  • 14 inches, such as NEC DKU800

Main parameters

In addition to the interface and size, the hard disk has the following parameters:

The unit of
Capacity The most important parameters of hard disks. At present, the capacities of hard disks are 36GB, 40GB, 45GB, 60GB, 75GB, 80GB, 120GB, 150GB, 160GB, 200GB, 250GB, 300GB, 320GB, 400GB, 500GB, 640GB, 750GB, 1TB, 1.5TB, 2TB, 2.5TB, 3TB, 4TB, 5TB, 6TB, 8TB, 10TB, 12TB, 14TB, 16TB, 18TB and many other specifications, but the calculation error...
Speed The number of revolutions per minute of the hard disk, in rpm (Revolutions Per Minute, the number of revolutions per minute), there are 4200rpm, 5400rpm, 5900rpm, 7200rpm, 10000rpm, 15000rpm, 18000rpm and other specifications. Generally speaking, the higher the rotation speed, the better the data transmission rate, but at the same time the higher the noise, power consumption and heat generation.
Cache There are mainly 2MB, 8MB, 16MB, 32MB, 64MB, 128MB, 256MB and other specifications.
Average seek time is ms (milliseconds), with 5.2ms, 8.5ms, 8.9ms, 12ms, etc.
Internal transmission speed includes the speed at which the head reads data from the disk into the cache, and the speed at which the head writes data from the cache to the disk. It can be used to evaluate the read and write speed and overall performance of the hard disk.

In addition to voltage, current, etc., solid state drives also have parameters such as master control and particle type (SLC, MLC, TLC, QLC). Generally, 3.5-inch hard disks in mechanical hard disks require 5V and 12V voltage, and 2.5-inch hard disks only need 5V voltage. However, because of the mechanical structure, the power consumption is usually higher than that of solid-state hard disks; the voltage of solid-state hard disks is generally 5V or 3.3V, and at the same time The power consumption of solid-state hard drives is usually low (power consumption is about 2.5W, current is about 500mA), and it is more energy-efficient than mechanical hard drives.

History of Development

Time Development content
1956 IBM'sIBM 305 RAMAC(English < span class="ilh-colon">: IBM 305 RAMAC) is the prototype of a modern hard disk, which is equivalent to the volume of two refrigerators, but its storage capacity is only 5MB.
1973 This year IBM 3340 came out, it has the nickname "Winchester", derived from its two 30MB storage units, which happened to be the caliber and filling of the famous "Winchester Rifle" at the time the amount. So far, the basic structure of the hard disk has been established.
1980 The company founded by two former IBM employees has developed a 5.25-inch 5MB hard drive ST506, which is the first desktop-oriented product, and the company is Seagate.
Late 1980s IBM launched MR (Magneto Resistive magnetoresistance) technology greatly improves the sensitivity of the magnetic head, and increases the storage density of the disk by dozens of times compared with the previous 20Mbpsi (bit/square inch). This technology lays the foundation for a huge increase in hard disk capacity. In 1991, IBM applied this technology to launch the first 3.5-inch 1GB hard drive.
From 1970 to 1991 The storage density of hard disk platters has been increasing at a rate of 25% to 30% per year; it has increased to 60% to 80% since 1991; so far, the speed has increased to 100% or even 200%. The amazing speed increase since 1997 has benefited from IBM's GMR (Giant Magneto Resistive (Giant Magneto Resistance) technology, which further improves the sensitivity of the magnetic head, thereby increasing the storage density.
1993 Conner Peripherals launched the CP30344 hard drive with a capacity of 340MB.
1995 In order to cooperate with Intel's LX chipset, Quantum and Intel jointly release UDMA 33 interface-EIDE standard increased the original interface data transmission rate from 16.6MB/s to 33MB/s. In the same year, Seagate developed fluid dynamic bearings (FDB, Fluid Dynamic Bearing) electric motor. The so-called FDB refers to the introduction of the technology on the gyroscope into the production of hard disks, replacing metal bearings with an oil film that is one-tenth of the diameter of a hair to reduce the noise and heat generation of the hard disk.
1996 Seagate acquired Conner Peripherals.
February 1998 UDMA 66 parameters are available.
October 2000 Maxtor acquires Quantum.
January 2003 Hitachi announced the completion of the US$2.05 billion acquisition of the IBM hard disk business unit and the establishment of Hitachi Global Storage Technologies a> (Hitachi Global Storage Technologies, Hitachi GST).
2005 Hitachi Central Storage and Seagate have both announced that they will begin to adopt disk vertical writing technology (perpendicular recording), the principle is to change the direction of the magnetic field parallel to the disc to vertical (90 degrees) to make fuller use of storage space.
December 21, 2005 Seagate announced the acquisition of Maxtor.
January 2007 Hitachi Global Storage Technology announced that it will sell the world's first 1Terabyte hard drive, more than a year later than the original schedule. The price of the hard drive is $399, and an average of 27.5MB of hard drive space can be purchased for every cent.
March 2011 Western Digital acquired Hitachi Global Storage Technology for $4.3 billion.
April 2011 Seagate announced that it has strengthened its strategic partnership with Samsung, and traditional hard drives are gradually being replaced by solid state drives.
December 2011 Seagate announced the acquisition of Samsung's hard drive business.

Existing major hard drive manufacturers

  • Western Digital (Western Digital) and its subsidiary Qantas Global Storage (HGST)
    • Hitachi Global Storage Technology: In 2011, it was acquired byWestern Digital and renamed Yuke Global Storage (HGST).
      • IBM: In 2003, the hard disk division was acquired by Hitachi.
  • Seagate
    • Conner: Acquired by Seagate in 1996.
    • Maxtor: Acquired by Seagate in 2006.
      • Quantum: In 2000, the hard drive division was acquired by Maxtor.
    • Samsung: In 2013, the hard disk business was acquired by Seagate.
  • Toshiba
    • Fujitsu: On February 18, 2009, the hard disk division was acquired by Toshiba.