机械硬盘---讨论

easylife

原帖由 深南大道于 2008-11-20 00:19 发表
原来伊凡兄也深受无尘室之苦啊
刚毕业是忍受了半年，现在偶尔进下无尘室。
5 j' K) O" }4 Y) p. N9 g机械硬盘这个东西，我们能搞定里面的轴承就算阿弥陀佛了
T; A* ]& T9 h, e固态硬盘，掉电会不会影响它所存储的数据呢？

" Z# ~$ q+ i) I* O5 ?9 |U盘算是固态硬盘的前期简化版, 存储好了的数据是不会丢的.

easylife

原帖由 螺旋线于 2008-11-20 09:14 发表
电子硬盘早就在用，比如工控机上，只是容量小。
1 n( C0 f% l6 a0 ^, h, b/ B( X# f电子硬盘替代机械硬盘是一定的。

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其实大约二十年前就有人说过机械硬盘将要被芯片存储器取代,
但机械硬盘又坚持发展了二十多年,
甚至在90年代后期迎来其行业发展的高峰期--那时候昆腾的待遇和环境和现在的GOOGLE相似,
而如今机械硬盘技术前景不明,几大生产商低价惨烈抢占市份额,有的公司运营举步为艰,行业发展前景不太乐观.
也许几年之后机械硬盘这个机电高度结合的高科技产物将消失在大家的视线中,只剩下一段可以追忆的历史....
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想想80年代全世界80多家硬盘生产商,到如今的希捷,西数,日立,东芝,富士通,三星和份额极少的易拓共7家公司,
" }' C$ }% ] Q' A$ `, V硬盘行业的竞争相当残酷

easylife

Hard Disk Drives

The hard disk drive in your system is the "data center" of the PC. It is here that all of your programs and data are stored between the occasions that you use the computer. Your hard disk (or disks) are the most important of the various types of permanent storage used in PCs (the others being floppy disks and other storage media such as CD-ROMs, tapes, removable drives, etc.) The hard disk differs from the others primarily in three ways: size (usually larger), speed (usually faster) and permanence (usually fixed in the PC and not removable).
' g( j( w+ k3 |. p% QHard disk drives are almost as amazing as microprocessors in terms of thetechnologythey use and how much progress they have made in terms of capacity, speed, and price in the last 20 years. The first PC hard disks had a capacity of 10 megabytes and a cost of over $100 per MB. Modern hard disks have capacities approaching 100gigabytesand a cost of less than 1 cent per MB! This represents an improvement of 1,000,000% in just under 20 years, or around 67%cumulativeimprovement per year. At the same time, the speed of the hard disk and itsinterfaceshave increased dramatically as well.

) z. t, w+ }: xYour hard disk plays a significant role in the following important aspects of yourcomputersystem:

• Performance:The hard disk plays a very important role in overall system performance, probably more than most people recognize (though that is changing now as hard drives get more of the attention they deserve). The speed at which the PC boots up and programs load is directly related to hard disk speed. The hard disk's performance is also critical when multitasking is being used or when processing large amounts of data such as graphics work, editing sound and video, or working with databases.
• Storage Capacity:This is kind of obvious, but a bigger hard disk lets you store more programs and data.
• Software Support:Newer software needs more space and faster hard disks to load it efficiently. It's easy to remember when 1 GB was a lot of disk space; heck, it's even easy to remember when 100 MB was a lot of disk space! Now a PC with even 1 GB is considered by many to be "crippled", since it can barely hold modern (inflated)operatingsystemfiles and a complement of standard business software.
• Reliability:One way to assess the importance of an item of hardware is to consider how much grief is caused if it fails. By this standard, the hard disk is the most important component by a long shot. As I often say, hardware can be replaced, but data cannot. A good quality hard disk, combined with smart maintenance and backup habits, can help ensure that the nightmare of data loss doesn't become part of your life.

This chapter takes a very detailed look at hard disks and how they work. This includes a full dissection of the internal components in the drive, a look at how data is formatted and stored, a discussion of performance issues, and a full analysis of the two main interfaces used toconnecthard disks to the rest of the PC. A discussion is also included about the many confusing issues regarding hard disks andBIOSversions, and support for the newer and larger hard disks currently on the market. Finally, a full description is given of logical hard disk structures and the functioning of the FAT and NTFSfilesystems, by far the most popular currently used by PCs.
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9 E1 n2 x6 j6 _6 X硬盘是电脑的数据中心....
明天翻译

1 S7 M) X( _ R: ^$ E[本帖最后由 easylife 于 2008-12-31 14:07 编辑]

胡雷

不太了解啊 看眼界了

easylife

原帖由 easylife于 2008-11-22 02:18 发表
1 p# g. ^3 ?9 [- ?6 I: D9 n Hard Disk Drives

The hard disk drive in your system is the "data center" of the PC. It is here that all of your programs and data are stored between the occasions that you use the computer. Your ha ...

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. G) V5 z) o$ m7 C. H硬盘在电脑中起着数据中心的作用。它储存了你使用电脑时所需要的一切程序和数据。硬盘是电脑里面永久性存储数据设备中最重要的存储设备（其他存储设备有软盘，和其它存储介质如光盘，磁带，移动硬盘等）。硬盘在三个方面有别于其他存储设备：尺寸（经常较其他的大），速度（较快）和持久性（它经常被固定在电脑里面并且不会被移动）。
在硬盘所采用的技术，和它在这最近20年里容量，速度及价格方面所发生的变化，可以说几乎和微处理器（的发展历程）一样令人惊叹。
9 j' g0 ^4 |; e% T2 ^第一台个人电脑的容量只有10MB，并且它的价格是100美圆每MB，
' h: [: _5 S6 T& c( n而现代硬盘有接近100GB的容量，价格低于1美分/MB！（注；此篇文章发表于大约在2005年）这些代表着在将近20年里，（硬盘）容量有1,000,000%，或者说每年近67%的累积增长。与此同时，硬盘在它的速度和它的接口方面也取得了极大的进步。

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硬盘在电脑系统里的如下方面扮演着重要的角色：
性能：硬盘在系统性能方面有着举足轻重的地位，可能远远高于大多数人们所认识到的（虽然这种情况正在改变，硬盘现在得到了它应该得到的关注）。系统启动和程序载入的速度直接和硬盘的速度相关。当系统执行多任务，或者处理大量的数据如图形方面的工作，音频和视频编辑，及数据库处理时，硬盘的性能也是个关键的影响效率的因素。
1 w; N6 }- k7 V9 [" Z, }存储容量：显而易见，更大的硬盘可以允许你储存更多的程序和数据。
: G/ C, }6 J7 Q/ U% C* I支持软件：新的程序需要更多的空间和更快的硬盘来使得它能被有效率地载入。大家还清楚的记得不久前1GB意味着相当大的存储空间，甚至也还清楚的记得没多久以前100MB对人们来说也是相当大的磁盘存储空间。而现在是配备着1GB硬盘的电脑会被人们认为是相当不适用的，因为它的存储容量还不能装下现在臃肿的操作系统和一些必备的标准商业软件。
可靠性：评估硬盘重要性的一种办法是想象下如果硬盘损坏了它将造成多大的损失。根据这个标准，长期来说硬盘是电脑里面最重要的部件，硬件能替换，但数据是不能的。一个质量可靠的硬盘，加上适当的维护和备份的好习惯，能确保数据丢失的噩梦不会发生在你的身上。

- W, u( R4 K j# `7 }9 ~0 h接下来将详细介绍下硬盘结构和它如何工作。接下来会将硬盘内部组件结构展现在大家眼前，介绍数据怎样被格式化和储存，及关于性能的讨论，并详细分析将硬盘连接到电脑其他器件上去的两中主要的接口。同时也将包括…..

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[本帖最后由 easylife 于 2008-12-31 14:08 编辑]

easylife

A Brief History of the Hard Disk Drive
$ N$ d8 ~6 e( s3 v% Y4 E, F( uHard disks are one of the most important and also one of the most interesting components within the PC. They have a long and interesting history dating back to the early 1950s. Perhaps one reason that I find them so fascinating is how well engineers over the last few decades have done at improving them in every respect: reliability, capacity, speed, power usage, and more.
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( B& K5 V8 X. V7 i2 h3 A* h..chart...
This excellent chart (shown in attached picture) shows the evolution of IBM hard disks over the past 15 years. Several
different form factors are illustrated, showing the progress that they have made over the
) m% ]; z3 L! e5 F. [0 d+ I3 u/ c$ C2 nyears in terms of capacity, along with projections for the future. 250 GB hard disks in
9 z! z* G3 X# n: @8 Ylaptops in five years? Based on past history, there's a good chance that it will in fact happen!
+ P- q# ~! N: ?2 i" D @Note that the scale on the left is logarithmic, not linear, and PC hard disks have one actuator.

- Q4 @9 ?; J0 i1 \1 b硬盘历史简述
硬盘是个人电脑里面最重要也是最有意思的组件。它们有着可追溯到20世纪50年代的漫长而有趣的历史。我发现它们之所以如此令人着迷的原因之一可能是，工程师们在短短的几十年内在硬盘的可靠性，容量，速度，能耗等方面取得了可喜的成绩。
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1 Q6 r" e; Z) r/ ? {# F+ V这张图表显示了IBM硬盘在过去的15年里面取得的进步。表中列出了几个不同的外形尺寸，显示了在过去这些年里在容量方面取得的进步，还有对未来的预测。5年里出现250GB的笔记本硬盘？基于过去的历史，这确实是很有可能发生的（注：实际上已经成为现实，文章是2005年发布）。请注意图表左边的标尺刻度是对数的，不是线性的，而且是基于硬盘只有一个磁头臂组（HSA）。
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( F N) |* n1 x" i2 N[本帖最后由 easylife 于 2008-11-22 23:27 编辑]

easylife

Life Without Hard Disk Drives

It's very hard for modern computerusersto even consider what "computer life" would be like without hard disk drives. After all, most of us now havebillionsandbillionsof bytes of information ready at our fingertips (apologies to Carl Sagan... ;^) ). What was using a computer like before we had hard disk drives? In a word...inconvenient.
! Y5 ]5 ]0 T" g J2 d) }! Z# VSome of the very earliest computers had no storage at all. Each time you wanted to run a program you would have to enter the program manually. Needless to say, this was a major pain in the butt. Even more than that, it made most of what we consider today to be computing impossible, since there was no easy to way to have a computer work with the same data over and over again. It was quickly realized that some sort of permanent storage was necessary if computers were to become truly useful tools.
$ C5 ^; n: o7 Q9 w* K( oThe first storage medium used on computers was actuallypaper. Programs and data were recorded using holes punched into paper tape or punch cards. A special reader used a beam of light to scan the cards or tape; where a hole was found it read a "1", and where the paper blocked the sensor, a "0" (or vice-versa). This was a pretty simple arrangement. I remember using a punch station, which was like a workstation where you typed characters and the machine punched the holes into the cards. While a great improvement overnothing, these cards were still very inconvenient to use. You basically had to write the entire program from scratch on paper, and get it working in your mind before you started trying to put it onto cards, because if you made a mistake you had to re-punch many of the cards. It was very hard to visualize what you were working with. The card readers had a tendency to jam (the old one at my high school was nicknamed the "IBM 1443 card chewer".) And heaven help you if you dropped a stack of cards on the floor...Still however, paper was used as the primary storage medium for many years.
The next big advance over paper was the creation ofmagnetic tape. Almost everyone has at least seen pictures of the large reels of tape used in older computers. Recording information in a similar to way to how audio is recorded on a tape, these magnetic tapes were much more flexible, durable and faster than paper tape or punch cards. Of course, tape is still used today on modern computers, but as a form ofofflineor secondary storage. Before hard disks, they were the primary storage for some computers. Their primary disadvantage is that they must be read linearly; it can take minutes to move from one end of the tape to the other, makingrandom accessimpractical.
Warning:Nostalgia mode activated. Be very afraid.
Personal computers developed much later than the early, large mainframes, and were therefore the beneficiaries of advancements in storagetechnologiesfairly early on in their existence. My first computer was purchased for me by my parents in 1980: an Apple ][. A great little machine for learning on, using it gave me a profound appreciation for the importance of storage: because it hadnone! No hard disk drive, not even a floppy disk drive. My choices were to type in programs by hand (which I did sometimes) or try to load them from acassette tape. Yes, an audio cassette tape. If you thought modern computertapedriveswere unreliable, you should have tried gettingthatto work!(Oh, and I also had to walk barefoot through three feet of snow to get to school... uphill both ways!)
, `- w/ e% _2 S2 ~I later purchased a low-density, single-sided floppy disk drive for my Apple. Boy, what a feeling of freedom that was! I could load and save programs and data easily, something I could never do before. That disk drive cost C$700 (back when the Canadian dollar was worth not much less than the U.S. dollar.) The biggest advantages offloppydisksover tapes are the ability to randomly access the data, and much better portability. They don't have nearly as much capacity however.
9 U' Z: I* I: M K FThe first IBMPCsalso had no hard disk drive, but rather employed one or two floppy disk drives. While of course far better than nothing, floppy disk drives were slow, small in capacity and relatively unreliable compared to even the earliest hard disks.

) ?& k3 h: o4 d1 a3 G- O[本帖最后由 easylife 于 2008-11-22 23:34 编辑]

easylife

对于现在电脑的使用者们来说，很难想象没有硬盘的“电脑”生活会变成什么样子。毕竟，现在大多数人手中（轻松）掌握着数以亿记字节的数据和信息。那没有硬盘之前使用电脑是个什么样子的情况？一个词—--不便。
一些最早期的电脑根本没有存储设备。每次当你想运行一个程序时，你必须手工输入程序。不用说，这是件很痛苦的事情。更麻烦的是，这样的操作方式使得我们今天称做计算的工作无法进行，因为在同一台电脑上多次使用同样的数据进行计算不是件容易的事情。很快人们认识到，如果想让计算机变成真正有用的工具，永久性的存储是必须的。
早期的存储介质是真正的纸。程序和数据记录通过在纸张或者卡片上冲孔来实现。特殊的读取设备使用一束光来扫描卡片或者纸带，但读到孔时记录为1，当某位置没有孔而光透不过去时，读为0（或者反之）。这种方式是非常简单的，我还记得使用过的冲孔机器，它就象是一个你输入字符然后机器在纸片上打孔的工作站。其实这个巨大的改进等于无用，这样纸带和卡片使用起来还是非常不方便。基本上你必须先将整个程序从无到有地在白纸上写出来，在脑海里考虑好，然后才去输入，因为如果你犯了错的必须重新冲孔许多的纸带。很难去想象你是在和什么打交道，卡片读取器经常堵塞（在我的高中学校将这种老机器戏称为“IBM 1443 卡片咀嚼器”）。如果你把一卷纸带失手掉在地上了的话，那你的请求神仙来搭救你了，呵呵。尽管如此，纸带还是作为主要的存储介质使用了很多年。
纸带之后下一个大的改进是磁带的发明。几乎所有人至少见过使用在旧电脑中的大盘磁带的图片。信息的记录类似于在录音磁带上录音的方式，磁带相对纸带和卡片来说更软，更耐用和速度更快。当然，磁带在现代的电脑中仍然在使用，但是是作为离线或者第二存储设备的形式。在硬盘出现之前，他们是电脑主要的存储设备，他们主要的缺点是必须被线性的读取，从磁带的一端到另一端要花费几分钟的时间，这使得随机读取不可行。
1 s/ X* Z8 V; p1 G7 L$ n7 o个人电脑是在早期大型电脑发展之后才开发出来的，因此它从出现就相当早的成为了存储技术进步的受益者。我的第一台电脑是我父母在1980年给我买的，Apple II,一台不错的用于学习的小机器，通过使用它使我对存储的重要性有非常深刻的认识，因为这台机器根本就没有存储设备！没硬盘，甚至没有软盘。我的选择是手工输入程序（过去经常这样做），或者试着从磁带上下载这些程序。告诉你那确实是磁带，就是录音磁带那种。…..
后来我为我的苹果机买了一张低密度，单面的软盘。朋友，那时候知道什么叫做自由！我能轻松地下载和保存程序，而有些是我以前无法做到的。那张软盘花了我700加元（那时候加元和美圆差不多）。相对磁带来说，软盘的最大优点就是能够随意地读取数据，而且携带也方便些，虽然它们没有和磁带那么多的容量。
第一台IBM个人电脑也没有硬盘，但配备有一张或者两张软盘，当然这些总比没有好，软盘较慢，容量小，而且哪怕和最早期的硬盘相比，它的可靠性也是较差的。

easylife

Early Disk Drives
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The very first disk drives were of course experiments. Researchers, particularly those at IBM, were working with a number of different technologies and concepts to try to develop a disk drive that would be feasible for commercial development. In fact, the very first drives were not "disk drives" at all--they used rotating cylindrical drums, upon which the magnetic patterns of data were stored. The drums were large and hard to work with.

The earliest "true" hard disks had the heads of the hard disk in contact with the surface of the disk. This was done to allow the low-sensitivity electronics of the day to be able to better read the magnetic fields on the surface of the disk. Unfortunately, manufacturing techniques were not nearly as sophisticated as they are now, and it was not possible to get the disk's surface as smooth as would be necessary to allow the head to slide smoothly over the surface of the disk at high speed while in contact with it. Over time the heads would wear out, or wear out the magnetic coating on the surface of the disk.
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The key technological breakthrough that enabled the creation of the modern hard disk came in the 1950s. IBM engineers realized that with the proper design the heads could be suspended above the surface of the disk and read the bits as they passed underneath. With this critical discovery that contact with the surface of the disk was not necessary, the basis for the modern hard disk was born.

The very first production hard disk was the IBM 305 RAMAC (Random Access Method of Accounting and Control), introduced on September 13, 1956. This beastie stored 5 million characters (approximately five megabytes, but a "character" in those days was only seven bits, not eight) on a whopping 50 disks, each 24 inches in diameter! Its areal density was about 2,000 bits per square inch; in comparison, today's drives have areal densities measured in billions of bits per square inch. The data transfer rate of this first drive was an impressive 8,800 bytes per second.

Over the succeeding years, the technology improved incrementally; areal density, capacity and performance all increased. In 1962, IBM introduced the model 1301 Advanced Disk File. The key advance of this disk drive was the creation of heads that floated, or flew, above the surface of the disk on an "air bearing", reducing the distance from the heads to the surface of the disks from 800 to 250 microinches.
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In 1973, IBM introduced the model 3340 disk drive, which is commonly considered to be the father of the modern hard disk. This unit had two separate spindles, one permanent and the other removable, each with a capacity of 30 MB. For this reason the disk was sometimes referred to as the "30-30". This name led to its being nicknamed the "Winchester" disk drive, after the famous "30-30" Winchester rifle. Using the first sealed internal environment and vastly improved "air bearing" technology, the Winchester disk drive greatly reduced the flying height of the disk: to only 17 microinches above the surface of the disk. Modern hard disks today still use many concepts first introduced in this early drive, and for this reason are sometimes still called "Winchester" drives.

& u) A9 k1 |- t$ C$ I) zThe first hard disk drive designed in the 5.25" form factor used in the first PCs was the Seagate ST-506. It featured four heads and a 5 MB capacity. IBM bypassed the ST-506 and chose the ST-412--a 10 MB disk in the same form factor--for the IBM PC/XT, making it the first hard disk drive widely used in the PC and PC-compatible world.

easylife

早期的硬盘
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最早期的硬盘当然是试验品。研究人员，特别是IBM的那些人，在当时正使用着一些不同的技术和概念，尝试开发出适合于商业运用的硬盘产品。实际上，最早期的驱动器根本不是硬盘，它们使用旋转的转盘，转盘上涂敷磁性物质存储数据。转盘非常大，操作起来比较困难。最早期硬盘的磁头和碟片是接触的，这样的话可以使（相对今天来说）敏感度较低的电子元器件在读取碟片表面磁场信号时变得容易些。但不幸的事情是，那时侯的制造技术不像现在这样先进，因此不能将碟片的表面加工的足够的光滑，从而允许磁头在高速运动并和碟片接触时平稳地在碟片表面滑动。时间长了后，要么磁头磨损，要么导致碟片表面的磁性层磨损。

关键技术的突破使得人们在20世纪50年代发明了现代硬盘。 IBM的工程师意识到通过合适的设计可以使磁头悬浮在盘片表面并读取磁头下方的数据。有了这个关键的发现后，磁头并不一定要接触盘片，现在硬盘的雏形型出现了。
& y8 R9 {& J3 X9 n/ n1 c6 O接下来这些年，技术不断进步，面密度，容量和性能都得到了提升。1962年，IBM推出了1301高级磁盘文件模型。这个硬盘关键的改进是磁头通过空气轴承在磁盘表面悬浮或者说飞行，将磁头到盘片的距离从800微英寸减少到250微英寸。
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# z) d+ p; y( Y6 B0 L* L; M8 `1 q1973年，IBM推出了3340磁盘驱动器----一般被普遍认为是现在硬盘驱动器的鼻祖。这个单元有两个独立的主轴马达，一个是永久性安装在里面而另一个是可移除的，每个马达都具有30MB的容量。由于这个原因这个硬盘有时又称为“30-30”，而这个名字又使得它拥有了另外一个别名“温彻斯特”硬盘，来源于著名的“30-30”温彻斯特来复枪。首次采用内部完全密封，并且极大地改进了空气轴承技术的温彻斯特硬盘极大地降低了飞行高度：距盘片表面只有17微英寸。现代硬盘仍然沿用着使用在早期硬盘上的许多概念，由于这个原因有时我们仍称他们为“温彻斯特”驱动器。
" X& b0 G- b* ]使用在个人电脑上的第一个5.25英寸硬盘是希捷的ST-506。它有四个磁头，容量5MB。IBM选择了ST-412，一个10MB容量的5.25英寸硬盘作为其IBM PC/XT的硬盘驱动器，而并没有选择ST-506，使得ST-41成为第一个广泛使用在个人电脑及其兼容设备上的硬盘驱动器。

! S) I3 G# e. n6 l1 a+ X[本帖最后由 easylife 于 2008-11-23 23:24 编辑]