機械硬盤---討論

easylife

原帖由 深南大道 于 2008-11-20 00:19 發表
原來伊凡兄也深受無塵室之苦啊
剛畢業是忍受了半年，現在偶爾進下無塵室。
0 n  e  r6 T7 Y+ o7 X, u$ e機械硬盤這個東西，我們能搞定里面的軸承就算阿彌陀佛了
固態硬盤，掉電會不會影響它所存儲的數據呢？

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# J2 l  N* z9 P3 ?U盤算是固態硬盤的前期簡化版, 存儲好了的數據是不會丟的.

easylife

原帖由 螺旋線 于 2008-11-20 09:14 發表
電子硬盤早就在用，比如工控機上，只是容量小。
電子硬盤替代機械硬盤是一定的。

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4 }2 ~; s& s- j9 K# B# x其實大約二十年前就有人說過機械硬盤將要被芯片存儲器取代,
- |2 p; w3 n7 {' M: [" r但機械硬盤又堅持發展了二十多年,
; e' ~4 _) h: K  w- w2 j! E甚至在90年代后期迎來其行業發展的高峰期--那時候昆騰的待遇和環境和現在的GOOGLE相似,
1 C$ @6 k; v! z; p& P而如今機械硬盤技術前景不明,幾大生產商低價慘烈搶占市份額,有的公司運營舉步為艱,行業發展前景不太樂觀.
; x1 z6 ]. x& s7 Q, J/ X也許幾年之后機械硬盤這個機電高度結合的高科技產物將消失在大家的視線中,只剩下一段可以追憶的歷史....
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想想80年代全世界80多家硬盤生產商,到如今的希捷,西數,日立,東芝,富士通,三星和份額極少的易拓共7家公司,
6 S) E! N; e' a; d. _硬盤行業的競爭相當殘酷

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).
Hard disk drives are almost as amazing as microprocessors in terms of the technology they 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 $100 per MB. Modern hard disks have capacities approaching 100 gigabytes and a cost of less than 1 cent per MB! This represents an improvement of 1,000,000% in just under 20 years, or around 67% cumulative improvement per year. At the same time, the speed of the hard disk and its interfaces have increased dramatically as well.
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5 V: l0 C$ y. F6 l# OYour hard disk plays a significant role in the following important aspects of your computer system:
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• 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) operating system files 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 to connect hard disks to the rest of the PC. A discussion is also included about the many confusing issues regarding hard disks and BIOS versions, 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 NTFS file systems, by far the most popular currently used by PCs.
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硬盤是電腦的數據中心....
明天翻譯

[ 本帖最后由 easylife 于 2008-12-31 14:07 編輯 ]

胡雷

不太了解啊 看眼界了

easylife

原帖由 easylife 于 2008-11-22 02:18 發表
Hard Disk Drives
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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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硬盤在電腦中起著數據中心的作用。它儲存了你使用電腦時所需要的一切程序和數據。硬盤是電腦里面永久性存儲數據設備中最重要的存儲設備（其他存儲設備有軟盤，和其它存儲介質如光盤，磁帶，移動硬盤等）。硬盤在三個方面有別于其他存儲設備：尺寸（經常較其他的大），速度（較快）和持久性（它經常被固定在電腦里面并且不會被移動）。
在硬盤所采用的技術，和它在這最近20年里容量，速度及價格方面所發生的變化，可以說幾乎和微處理器（的發展歷程）一樣令人驚嘆。
第一臺個人電腦的容量只有10MB，并且它的價格是100美圓每MB，
; L/ [* i+ Y; d! c$ w而現代硬盤有接近100GB的容量，價格低于1美分/MB！（注；此篇文章發表于大約在2005年）這些代表著在將近20年里，（硬盤）容量有1,000,000%，或者說每年近67%的累積增長。與此同時，硬盤在它的速度和它的接口方面也取得了極大的進步。

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7 l+ I! c- U' S- \. j& Y% V' X+ o' Q; ?硬盤在電腦系統里的如下方面扮演著重要的角色：
性能：硬盤在系統性能方面有著舉足輕重的地位，可能遠遠高于大多數人們所認識到的（雖然這種情況正在改變，硬盤現在得到了它應該得到的關注）。系統啟動和程序載入的速度直接和硬盤的速度相關。當系統執行多任務，或者處理大量的數據如圖形方面的工作，音頻和視頻編輯，及數據庫處理時，硬盤的性能也是個關鍵的影響效率的因素。
存儲容量：顯而易見，更大的硬盤可以允許你儲存更多的程序和數據。
支持軟件：新的程序需要更多的空間和更快的硬盤來使得它能被有效率地載入。大家還清楚的記得不久前1GB意味著相當大的存儲空間，甚至也還清楚的記得沒多久以前100MB對人們來說也是相當大的磁盤存儲空間。而現在是配備著1GB硬盤的電腦會被人們認為是相當不適用的，因為它的存儲容量還不能裝下現在臃腫的操作系統和一些必備的標準商業軟件。
可靠性：評估硬盤重要性的一種辦法是想象下如果硬盤損壞了它將造成多大的損失。根據這個標準，長期來說硬盤是電腦里面最重要的部件，硬件能替換，但數據是不能的。一個質量可靠的硬盤，加上適當的維護和備份的好習慣，能確保數據丟失的噩夢不會發生在你的身上。

接下來將詳細介紹下硬盤結構和它如何工作。接下來會將硬盤內部組件結構展現在大家眼前，介紹數據怎樣被格式化和儲存，及關于性能的討論，并詳細分析將硬盤連接到電腦其他器件上去的兩中主要的接口。同時也將包括…..
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, N1 N9 w& f  C; ~7 P[ 本帖最后由 easylife 于 2008-12-31 14:08 編輯 ]

easylife

A Brief History of the Hard Disk Drive
Hard 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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8 Z, F) d  G1 q0 J0 b' S* J: ?..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
3 ~. t& L. C( }: t9 [years in terms of capacity, along with projections for the future. 250 GB hard disks in
6 ^+ ~8 }% T% l$ ~0 C+ g* x1 ~' ulaptops in five years? Based on past history, there's a good chance that it will in fact happen!
' |. i0 G, w+ F7 |+ W: Y2 UNote that the scale on the left is logarithmic, not linear, and PC hard disks have one actuator.
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硬盤歷史簡述
硬盤是個人電腦里面最重要也是最有意思的組件。它們有著可追溯到20世紀50年代的漫長而有趣的歷史。我發現它們之所以如此令人著迷的原因之一可能是，工程師們在短短的幾十年內在硬盤的可靠性，容量，速度，能耗等方面取得了可喜的成績。

這張圖表顯示了IBM硬盤在過去的15年里面取得的進步。表中列出了幾個不同的外形尺寸，顯示了在過去這些年里在容量方面取得的進步，還有對未來的預測。5年里出現250GB的筆記本硬盤？基于過去的歷史，這確實是很有可能發生的（注：實際上已經成為現實，文章是2005年發布）。請注意圖表左邊的標尺刻度是對數的，不是線性的，而且是基于硬盤只有一個磁頭臂組（HSA）。
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" v8 m; d$ p) C  }. e/ Z5 X- u3 K[ 本帖最后由 easylife 于 2008-11-22 23:27 編輯 ]

easylife

Life Without Hard Disk Drives

It's very hard for modern computer users to even consider what "computer life" would be like without hard disk drives. After all, most of us now have billions and billions of 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.
6 \1 n9 X6 t% S. M9 hSome 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.
) `* }- K9 v9 GThe first storage medium used on computers was actually paper. 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 over nothing, 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 of magnetic 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 of offline or 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, making random access impractical.
Warning: Nostalgia mode activated. Be very afraid.
  z) b9 a" }8 X! [Personal computers developed much later than the early, large mainframes, and were therefore the beneficiaries of advancements in storage technologies fairly 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 had none! 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 a cassette tape. Yes, an audio cassette tape. If you thought modern computer tape drives were unreliable, you should have tried getting that to work! (Oh, and I also had to walk barefoot through three feet of snow to get to school... uphill both ways!)
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 of floppy disks over tapes are the ability to randomly access the data, and much better portability. They don't have nearly as much capacity however.
1 a( L* ^# p# `The first IBM PCs also 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.
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[ 本帖最后由 easylife 于 2008-11-22 23:34 編輯 ]

easylife

對于現在電腦的使用者們來說，很難想象沒有硬盤的“電腦”生活會變成什么樣子。畢竟，現在大多數人手中（輕松）掌握著數以億記字節的數據和信息。那沒有硬盤之前使用電腦是個什么樣子的情況？一個詞—--不便。
: }; M  i8 _4 Y一些最早期的電腦根本沒有存儲設備。每次當你想運行一個程序時，你必須手工輸入程序。不用說，這是件很痛苦的事情。更麻煩的是，這樣的操作方式使得我們今天稱做計算的工作無法進行，因為在同一臺電腦上多次使用同樣的數據進行計算不是件容易的事情。很快人們認識到，如果想讓計算機變成真正有用的工具，永久性的存儲是必須的。
早期的存儲介質是真正的紙。程序和數據記錄通過在紙張或者卡片上沖孔來實現。特殊的讀取設備使用一束光來掃描卡片或者紙帶，但讀到孔時記錄為1，當某位置沒有孔而光透不過去時，讀為0（或者反之）。這種方式是非常簡單的，我還記得使用過的沖孔機器，它就象是一個你輸入字符然后機器在紙片上打孔的工作站。其實這個巨大的改進等于無用，這樣紙帶和卡片使用起來還是非常不方便。基本上你必須先將整個程序從無到有地在白紙上寫出來，在腦海里考慮好，然后才去輸入，因為如果你犯了錯的必須重新沖孔許多的紙帶。很難去想象你是在和什么打交道，卡片讀取器經常堵塞（在我的高中學校將這種老機器戲稱為“IBM 1443 卡片咀嚼器”）。如果你把一卷紙帶失手掉在地上了的話，那你的請求神仙來搭救你了，呵呵。盡管如此，紙帶還是作為主要的存儲介質使用了很多年。
3 r4 T: H# a" p紙帶之后下一個大的改進是磁帶的發明。幾乎所有人至少見過使用在舊電腦中的大盤磁帶的圖片。信息的記錄類似于在錄音磁帶上錄音的方式，磁帶相對紙帶和卡片來說更軟，更耐用和速度更快。當然，磁帶在現代的電腦中仍然在使用，但是是作為離線或者第二存儲設備的形式。在硬盤出現之前，他們是電腦主要的存儲設備，他們主要的缺點是必須被線性的讀取，從磁帶的一端到另一端要花費幾分鐘的時間，這使得隨機讀取不可行。
0 R) i1 S. n- x  T# E8 H個人電腦是在早期大型電腦發展之后才開發出來的，因此它從出現就相當早的成為了存儲技術進步的受益者。我的第一臺電腦是我父母在1980年給我買的，Apple II,一臺不錯的用于學習的小機器，通過使用它使我對存儲的重要性有非常深刻的認識，因為這臺機器根本就沒有存儲設備！沒硬盤，甚至沒有軟盤。我的選擇是手工輸入程序（過去經常這樣做），或者試著從磁帶上下載這些程序。告訴你那確實是磁帶，就是錄音磁帶那種?！?.
' ^+ D4 d* n9 F5 @2 E# u4 _后來我為我的蘋果機買了一張低密度，單面的軟盤。朋友，那時候知道什么叫做自由！我能輕松地下載和保存程序，而有些是我以前無法做到的。那張軟盤花了我700加元（那時候加元和美圓差不多）。相對磁帶來說，軟盤的最大優點就是能夠隨意地讀取數據，而且攜帶也方便些，雖然它們沒有和磁帶那么多的容量。
" b2 s! c+ E# _/ ]0 ?4 O第一臺IBM個人電腦也沒有硬盤，但配備有一張或者兩張軟盤，當然這些總比沒有好，軟盤較慢，容量小，而且哪怕和最早期的硬盤相比，它的可靠性也是較差的。

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.
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" J5 b0 s& V! _& HThe 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.

. E% n6 G$ w5 u. d8 tThe 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.

3 n( o$ w& ]: ?3 nThe 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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" K  k/ X. P  u, O9 L+ AIn 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.
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* x% q' J5 g  \The 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

早期的硬盤
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) I0 w/ ~( B) V3 J  l; ?% ]# e最早期的硬盤當然是試驗品。研究人員，特別是IBM的那些人，在當時正使用著一些不同的技術和概念，嘗試開發出適合于商業運用的硬盤產品。實際上，最早期的驅動器根本不是硬盤，它們使用旋轉的轉盤，轉盤上涂敷磁性物質存儲數據。轉盤非常大，操作起來比較困難。最早期硬盤的磁頭和碟片是接觸的，這樣的話可以使（相對今天來說）敏感度較低的電子元器件在讀取碟片表面磁場信號時變得容易些。但不幸的事情是，那時侯的制造技術不像現在這樣先進，因此不能將碟片的表面加工的足夠的光滑，從而允許磁頭在高速運動并和碟片接觸時平穩地在碟片表面滑動。時間長了后，要么磁頭磨損，要么導致碟片表面的磁性層磨損。
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關鍵技術的突破使得人們在20世紀50年代發明了現代硬盤。 IBM的工程師意識到通過合適的設計可以使磁頭懸浮在盤片表面并讀取磁頭下方的數據。有了這個關鍵的發現后，磁頭并不一定要接觸盤片，現在硬盤的雛形型出現了。
接下來這些年，技術不斷進步，面密度，容量和性能都得到了提升。1962年，IBM推出了1301高級磁盤文件模型。這個硬盤關鍵的改進是磁頭通過空氣軸承在磁盤表面懸浮或者說飛行，將磁頭到盤片的距離從800微英寸減少到250微英寸。

- q0 D7 f( K5 M( ^. l! N/ ?0 @4 n1973年，IBM推出了3340磁盤驅動器----一般被普遍認為是現在硬盤驅動器的鼻祖。這個單元有兩個獨立的主軸馬達，一個是永久性安裝在里面而另一個是可移除的，每個馬達都具有30MB的容量。由于這個原因這個硬盤有時又稱為“30-30”，而這個名字又使得它擁有了另外一個別名“溫徹斯特”硬盤，來源于著名的“30-30”溫徹斯特來復槍。首次采用內部完全密封，并且極大地改進了空氣軸承技術的溫徹斯特硬盤極大地降低了飛行高度：距盤片表面只有17微英寸?，F代硬盤仍然沿用著使用在早期硬盤上的許多概念，由于這個原因有時我們仍稱他們為“溫徹斯特”驅動器。
* U( d& V, p& g2 f9 ]使用在個人電腦上的第一個5.25英寸硬盤是希捷的ST-506。它有四個磁頭，容量5MB。IBM選擇了ST-412，一個10MB容量的5.25英寸硬盤作為其IBM PC/XT的硬盤驅動器，而并沒有選擇ST-506，使得ST-41成為第一個廣泛使用在個人電腦及其兼容設備上的硬盤驅動器。

[ 本帖最后由 easylife 于 2008-11-23 23:24 編輯 ]