This article will introduce you to disk geometry.本文将向您介绍磁盘几何。 You will learn some of the terminology that is required in order to understand the internal construction of a disk.您将学习上的一些术语是为了建设需要的理解内部。
Platters 盘
A platter is a physical object (actually, a plate) that resides inside the hard disk and is responsible for storing the data.一盘是一个物理对象（实际上，一板）驻留在硬盘内，并负责存储数据。 A platter is similar to a record on an old record player—the main difference being that a hard disk has many platters, while a record player only holds one record at a time.一盘类似，达到创纪录的老唱机，盘片的主要区别是，一个硬盘上有很多，而创纪录的球员只拥有一次录制。
The platters are very much like records on a record player in the sense that they spin around in a circle on a spindle that runs through the center of all the platters. Each platter has two sides for storing information, and each side of the platter has a unique ID.该盘是非常喜欢的感觉就记录在一个记录器，它们围绕旋转的盘片在一个圆圈上所有的主轴是贯穿中心。每个盘片有两个方面的信息储存，每盘端的有一个唯一的ID。 The ID for the first side of the first platter is 0, and each side increases by 1.盘片的编号为第一的第一面为0，而每增加1方。 For example, if there were two platters in the disk, the first platter would have Side 0 and Side 1, while the second platter would have Side 2 and Side 3.例如，如果有两个磁盘盘片的，第一盘将有副作用0和1面，而第二盘将有副作用2和第3方。
Since there will be a writing mechanism—a head—for each side of the platter, many people use the terms “head” and “side” interchangeably.由于将有一个写作的机制- 1的盘头，为每一个方面，很多人使用术语“头”和“方”可以互换。 The head is more accurately called the read/write head , because it will move over the disk surface and read or write to the disk.头部更准确地称为读/写头 ，因为它会移到磁盘表面和读取或写入到磁盘。 Like a needle on a record player, the read/write head moves over the surface of the disk with the help of an arm, called the actuator arm (also known as the head positioning mechanism ).如同一针上一纪录的球员，读/写头移动的手臂在表面的帮助与磁盘，称为执行器臂 （也称为头机制定位 ）。
There is a read/write head for each platter surface on the disk.有一个读/写盘片上的每个磁盘表面头。 When information is written to the disk, the read/write head will move to the same track on all platters in a single movement and then write to the same track on all platters.当信息被写入到磁盘时，读/写磁头会提出在一个单一的运动，所有盘片相同的轨道上，然后写跟踪所有盘片相同。 The actuator arm has multiple read/write heads on it.执行器臂有多个读/写头的。
Tracks 曲目
Just as there are grooves, or tracks, on a record or music CD, there are also tracks on each platter.正如有沟槽，或路轨光盘，记录或音乐，也有跟踪每个盘片。 These tracks are evenly spaced across the platter's surface.这些轨道是均匀分布的整个盘片的表面。
Sectors 行业
The platter is divided into pie slices, thus dividing the tracks into 512-byte sectors. Sectors are the actual storage areas for data, and each has an address that is made up of the platter side number, the track number, and the sector number on that track.盘片被划分成扇形，从而字节扇区划分的轨道成512。行业领域是数据的实际存储，而每一种都有一个地址，它是一面数字组成的拼盘，轨道数和扇区数该轨道。
For the Core Hardware exam, know that a low-level format is performed by the manufacturer and is responsible for preparing the disk for data storage by creating the tracks and sectors.对于核心硬件考试，要知道一个低级别的格式是由制造商进行，并负责跟踪和部门编制的数据存储在磁盘上创建。
Clusters 集群
A group of any number of sectors can make up a cluster .一个部门的任何组数字可以组成一个集群 。 When a partition is formatted, the file system will determine the cluster size based off the partition size.当一个分区被格式化，文件系统的簇大小，将决定关闭该分区的大小。 For example, a partition that is 2GB in size formatted as FAT will use a 32K-cluster size. That same 2GB partition formatted as FAT32 will use only a 4K-cluster size. Having a partition use a 4K-cluster size means there will be 8 sectors that make up a cluster.例如，一个分区大小是2GB的簇大小格式化为FAT将使用一个32K的。就在同2GB的分区格式化为FAT32的规模将只使用一个4K的联网。拥有一个分区使用4K的簇大小意味着将有八部门构成一个群集。 Keep in mind that once a file has been saved to the cluster, no other file can occupy that cluster.请记住，一旦文件已被保存到群集，没有其他文件可以占用的群集。 For example, if you had a 32K-cluster size and you saved a 3K file to the hard disk, the file would be saved to an empty cluster—but only 3K of it would be used, and the remaining 29K would be left unused.例如，如果你有一个32K的簇大小和一个3K的文件保存到硬盘上，该文件将被保存到一个空的簇，但是只有它的将是3K的使用，其余将闲置29,000。 The remaining 29K is now considered unusable space; no other file can be saved to that unused 29 K.其余29,000目前被认为是无法使用的空间，没有其他文件可以保存到29日，未使用的光
Cylinders 缸
Each platter in the disk contains the same number of tracks; these tracks are numbered from the outside in, starting with zero.每个磁盘盘片中包含相同数量的曲目，这些曲目的编号从外面，从零开始的。 For example, if there were ten tracks on a platter, the track closest to the edge of the platter would be Track 0, while the track closest to the center would be Track 9.例如，如果有一盘10轨迹，轨道最接近盘边缘的将是0磁道，而轨道最接近中心将跟踪9。
A cylinder consists of the same track on both sides of all the platters.一缸组成的盘片上，双方都在同一轨道。 In other words, when you reference Track 0, you reference a particular track on a particular platter, but when you reference Cylinder 0, you reference Track 0 on all platters. If you know the number of cylinders, heads, and sectors per track, you can calculate the size of a disk.在口头上，其他当您引用0磁道，您引用一个特定的盘片上一个特定的轨道，但是当你引用柱面0，你参考0磁道上的所有盘片。如果你知道元首气缸数，并跟踪每个部门，你可以计算磁盘大小的一个。 For example, if you have a drive that has 4,092 cylinders, 16 heads, and 63 sectors per track, the size of the disk would be 2,111,864,832 bytes (2.1GB).例如，如果您有一个驱动器具有4092柱面，16个磁头，每磁道扇区和63，磁盘的大小将是2111864832字节（2.1GB）。 The formula to calculate the size of the disk is Cylinders × Heads × Sectors × 512 bytes per sector.该公式计算出的磁盘大小是缸头× × × 512行业每扇区字节数。
Read/write process 读/写过程
Platters are divided into 512 byte sectors.盘片被分成512字节扇区。 These sectors are the area on the platter that data is written to.这些部门都是以书面的盘片面积上的数据。 The platters have a magnetic coating applied to them that is extremely sensitive to magnetism. While the platters are rotating in a circle, the read/write heads are moved over the disk surface to the location where they need to write (or save) information.该盘有磁性涂料适用于他们，是非常敏感的磁性。尽管盘片是旋转成一个圆圈，读/写信息头）被移到了磁盘表面的位置，他们需要编写（或保存。 The read/write heads do not actually touch the surface of the disk platters; instead, they “hover” about ten micro-inches (or millionths of an inch) above—that's not even enough space to place a hair between the read/write head and the platter's surface.读/写磁头实际上并不接触盘片表面的磁盘，而是他们“悬停”约10微英寸（或英寸万分之一的）以上这还没有足够的空间放置/写一毛之间的阅读头与盘片表面。 This design helps improve disk performance, because a read/write head that made contact with the platter would cause friction, slowing down the rotation speed of the disk.这种设计有助于提高磁盘性能，因为一个读/写磁头，使得盘片的接触会引起摩擦，放慢速度的旋转盘。
While the platters spin around in circles, the read/write head moves from track to track until it reaches the desired one.虽然盘片旋转兜圈子，读/写头移动到轨道跟踪，直到达到预期的1。 Then it waits for the appropriate sector to move underneath it, at which time the read/write head is energized to apply a magnetic charge to the particles in the disk coating.然后，等待下移动它，为部门的恰当其时的读/写头通电套用到磁盘磁荷的粒子在涂层。 This changes the particle binary state from zero to one, thus creating data.这改变了二进制状态从零到一个粒子，从而造成数据。
Performance 表现
Disk performance can be measured in terms of several important characteristics: seek time, latency, access time, and the spin speed of the disk.磁盘性能，可衡量的几个重要方面的特点：寻找时间，等待时间，存取时间，速度和旋转的磁盘。
Measuring Hard Disk Performance 衡量硬盘性能
Seek time is the time it takes to move the read/write heads to the desired track. 寻找时间是花费的时间移动读/写磁头到所需的轨道。 Seek time is a calculated average, since the time it takes to move to the desired track will differ from one instance to another. For example, if the read/write heads are on Track 1, they will take a longer amount of time moving to Track 12 than to Track 3 (because the distance is greater between Track 1 and Track 12).寻道时间是一个计算的平均，因为所花费的时间移动到所需的跑道将实例从一个到另一个不同。举例来说，如果读/写磁头1的轨道上，他们将采取一系列时间较长的数额向移动田径田径12比3（因为距离是12和1之间更大的田径田径）。 Seek time is measured in milliseconds, or millionths of a second.寻找时间以毫秒为单位来衡量，或第二百万分之一的一个。
Latency is the time it takes for the appropriate sector to move under the read/write head. 延迟是部门需要的时间为适当的动议下的读/写头。 Latency is measured in milliseconds. Access time Access time is a term used to describe the overall speed of the disk.等待时间是毫秒计。存取时间的磁盘访问时间是一个术语，用来描述总体速度。 It is a combination of seek time and latency.这是一个延迟时间，寻求结合。 The lower the access time, the better.存取时间越低，越好。
Spin speed is the speed at which the platters spin in a circle, measured in revolutions (rotations) per minute, or rpm. 旋转速度是速度而盘片旋转成一个圆圈，每分钟转速测量转（转动），每分钟或。 The larger the rpm value the faster the disk, which means less latency.值越大，转速越快的硬盘，这意味着更少的延迟。
Master boot record 主引导记录
While I'm discussing disk geometry, I should make a brief comment about the Master Boot Record.虽然我讨论磁盘几何，我要一个简短的评论引导记录有关硕士。 The Master Boot Record (MBR) is the first sector on the first track of the first side of the first platter; it holds the operating system boot code that controls the loading of the operating system. 主引导记录（MBR）是第一盘的第一个扇区的第一首曲目的一面，它拥有操作系统的启动代码，加载控制系统的运作。
The MBR also holds drive characteristics—such as the partition table.膜生物反应器还持有驾驶特性，如分区表。 During the boot process the system has to find a primary partition that is active and it will do this by looking in the boot record.在引导过程的系统必须找到一个主分区处于活动状态，它会记录该启动了前瞻性的。
In general, if anything goes wrong with the MBR, you will be unable to boot the system. Since this boot record is always found in the same location on every disk, it becomes very easy for developers to write viruses that will modify or corrupt it. This is one reason you should always run virus detection software.一般来说，如果有什么出错的膜生物反应器，你将无法启动系统的磁盘。由于这是每一个引导记录总是发现在同一位置上，它变得非常容易的开发编写病毒，将它修改或损坏。这是一个原因，你应该始终运行病毒检测软件。
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