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| [[Image:Cylinder Head Sector.svg|right|Cylinder, head, and sector of a hard drive.]]
| | == White wings engulfed many materials == |
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| '''Cylinder-head-sector''', also known as '''CHS''', was an early method for giving addresses to each physical block of data on a [[hard disk drive]]. In the case of ''floppy'' drives, for which the same exact ''diskette'' medium can be truly ''[[disk formatting|low-level formatted]]'' to different capacities, this is still true.
| | Precious materials to devour white wings! White wings engulfed many materials, the damage it can restore some of the above injury, during the recovery process, but [http://www.nrcil.net/fancybox/lib/rakuten_LV_83.html ルイヴィトン 六本木] also once again expelled out a pool of blood, out of that pool of blood after the expulsion of God also embodies a drop of blood.<br><br>now own a total of two [http://www.nrcil.net/fancybox/lib/rakuten_LV_41.html ルイヴィトン 新品] drops of blood of God.<br>Before<br>war and when Yaozu, boat Mausoleum of God with a drop of blood, but also with a drop of the stars of God tower [http://www.nrcil.net/fancybox/lib/rakuten_LV_11.html ルイヴィトン 靴] blood.<br><br>'want to [http://www.nrcil.net/fancybox/lib/rakuten_LV_35.html ルイヴィトン 財布 一覧] pour the United States.' mountain ride off even shaking his head, 'I said, you kill a master of the universe, [http://www.nrcil.net/fancybox/lib/rakuten_LV_117.html ルイヴィトン旅行バッグ] I can help you refining a treasure. This is the first time you ...... no precious materials teacher to help [http://www.nrcil.net/fancybox/lib/rakuten_LV_50.html ルイヴィトン 鞄] you out. happen I refining two? waiting for you to say scrapping a Master of the Universe. '<br><br>'teacher.' Luo Feng Link Road, 'Yaozu a war, I kill one spot, also with the [http://www.nrcil.net/fancybox/lib/rakuten_LV_136.html ルイヴィトンの新作バッグ] boat's Mausoleum received three! those three are now dead ...... I killed it [http://www.nrcil.net/fancybox/lib/rakuten_LV_12.html ルイヴィトンルイヴィトン] should be considered of it. '<br><br>'dead? initial universe is dead, right?' sit off the mountain even |
| | 相关的主题文章： |
| | <ul> |
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| | <li>[http://www.bjcfjy.com/blog/?action-viewnews-itemid-9756 http://www.bjcfjy.com/blog/?action-viewnews-itemid-9756]</li> |
| | |
| | <li>[http://www.fhgc123.com/plus/feedback.php?aid=12 http://www.fhgc123.com/plus/feedback.php?aid=12]</li> |
| | |
| | <li>[http://www.horrorfind.com/horror-find-bin/to-your-horror/search.cgi http://www.horrorfind.com/horror-find-bin/to-your-horror/search.cgi]</li> |
| | |
| | </ul> |
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| Though CHS values no longer have a direct physical relationship to the data stored on disks, virtual CHS values (which can be ''translated'' by disk electronics or software) are still being used by many utility programs.
| | == but also the ears Luo Feng faint echoing 'Master == |
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| ==Definitions==
| | Lin? 'Luo Feng frown, hearts and more angry,' Why did he kill me, and he had no injustice Wu [http://www.nrcil.net/fancybox/lib/rakuten_LV_79.html 財布 ルイヴィトン メンズ] Chou. '<br><br>'presumably to treasure it.' Baba Ta Road.<br><br>'He knows how I converted treasures, lightning is often someone into the castle.' Luo Feng feel very uncomfortable, especially the two bodyguards, [http://www.nrcil.net/fancybox/lib/rakuten_LV_97.html ルイヴィトン マルチカラー 財布] iron Nanhe his death, Ao bones are almost finished.<br><br>people of non-vegetation, ruthless Practice makes perfect.<br><br>Although only bought [http://www.nrcil.net/fancybox/lib/rakuten_LV_9.html ルイヴィトン 通販] slaves, but also the ears Luo Feng faint echoing 'Master! Run!' scream sound, in times of danger, iron Procyon and Ao are fractured bone Yongming Qudang.<br><br>'Brolin, Brolin!!!' Luo Feng hearts are burning anger difficult subject.<br><br>hurts [http://www.nrcil.net/fancybox/lib/rakuten_LV_68.html ルイヴィトン 長財布 中古]!<br><br>'Luo Feng, [http://www.nrcil.net/fancybox/lib/rakuten_LV_72.html ルイヴィトン旅行バッグ] temporarily not painful. though you useless monster Golden Horn, however, you use the spacecraft, but also [http://www.nrcil.net/fancybox/lib/rakuten_LV_11.html ルイヴィトン 新品] big [http://www.nrcil.net/fancybox/lib/rakuten_LV_130.html ルイヴィトン 靴] trouble.' Baba Ta Road, 'more than one hundred meters in length and width of the huge [http://www.nrcil.net/fancybox/lib/rakuten_LV_130.html ルイヴィトン 靴] storage space artifacts, very precious. did I give you |
| | | 相关的主题文章： |
| CHS addressing is the process of identifying individual [[#Sectors|sectors]] on a disk by their position in a [[#Tracks|track]], where the track is determined by the [[#Heads|head]] and [[#Cylinders|cylinder]] numbers. The terms are explained bottom up, for disk addressing the ''sector'' is the smallest unit. Disk controllers can introduce address translations to map logical to physical positions, e.g., [[zone bit recording]] stores fewer sectors in shorter (inner) tracks, physical disk formats are not necessarily cylindrical, and sector numbers in a track can be skewed.
| | <ul> |
| | | |
| ===Tracks===
| | <li>[http://hongyingmingyu.gotoip4.com/forum.php?mod=viewthread&tid=3820 http://hongyingmingyu.gotoip4.com/forum.php?mod=viewthread&tid=3820]</li> |
| The [[track (disk drive)|track]]s are the thin [[concentric]] circular strips of sectors. At least one head is required to read a single track. With respect to disk geometries the terms ''track'' and ''cylinder'' are closely related. For a single or double sided [[floppy disk]] ''track'' is the common term; and for more than two heads ''cylinder'' is the common term. Strictly speaking a ''track'' is a given <code><abbr title="Cylinder">C<abbr><abbr title="Head">H</abbr></code> combination consisting of
| | |
| <code><abbr title="Sectors Per Track">SPT<abbr></code> sectors, while a ''cylinder'' consists of | | <li>[http://www.trip8sz.cn/home/space.php?uid=40559&do=blog&id=4182 http://www.trip8sz.cn/home/space.php?uid=40559&do=blog&id=4182]</li> |
| <code>SPT×<abbr title="Heads">H<abbr></code> sectors. | | |
| | | <li>[http://forum.enterworldnet.com/showthread.php?p=89148#post89148 http://forum.enterworldnet.com/showthread.php?p=89148#post89148]</li> |
| ===Cylinders===
| | |
| {{Merge from|Cylinder (disk drive)|date=July 2011}}
| | </ul> |
| | |
| A [[cylinder (disk drive)|cylinder]] comprises the same track number on each platter, spanning all such tracks across each platter surface that is able to store data (without regard to whether or not the track is "bad"). Thus, it is a three-dimensional structure. Any track comprising part of a specific cylinder can be written to and read from while the actuator assembly remains stationary, and one way in which hard drive manufacturers have increased drive access speed has been by increasing the number of platters which can be read at the same time.
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| ===Sectors===
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| A [[disk sector|sector]] is the smallest storage unit that is [[Memory address|addressable]] by a hard drive, and all information stored by the hard drive is recorded in sectors.
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| | |
| Floppy disks and controllers use physical sector sizes of 128, 256, 512 and 1024 bytes (e.g., PC/AX), whereby formats with 512 bytes per physical sector became dominant in the 1980s.<ref name="Ecma-107">{{ cite web | url = http://www.ecma-international.org/publications/standards/Ecma-107.htm | title = Volume and File Structure of Disk Cartridges for Information Interchange | work = Standard ECMA-107 (2nd ed., June 1995) | publisher = [[Ecma International|ECMA]] | year = 1995 | accessdate = 2011-07-30 }}</ref><ref>{{cite web
| |
| |url=http://support.microsoft.com/kb/75131
| |
| |title=Standard Floppy Disk Formats Supported by MS-DOS
| |
| |work=KB75131
| |
| |date=2003-05-12
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| |publisher=[[Microsoft Knowledge Base]]
| |
| |accessdate=2011-07-31}}</ref>
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| | |
| The most common physical sector size for harddisks today is 512 bytes, but there have been hard disks with 520 bytes per sector as well for non-IBM compatible machines. In 2005 some [[Seagate Technology|Seagate]] custom hard disks used sector sizes of 1024 bytes per sector. [[Advanced Format]] hard disks use 4096 bytes per physical sector ([[4Kn]])<ref>{{cite web
| |
| |url=http://www.anandtech.com/show/2888
| |
| |title=Western Digital’s Advanced Format: The 4K Sector Transition Begins
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| |publisher=[[AnandTech]]
| |
| |date=2009-12-18
| |
| |accessdate=2011-07-29}}</ref> since 2010, but will also be able to emulate 512 byte sectors ([[512e]]) for a transitional period.<ref>{{cite web
| |
| | url=http://www.hitachigst.com/tech/techlib.nsf/techdocs/3D2E8D174ACEA749882577AE006F3F05/$file/AFtechbrief.pdf
| |
| | title=Advanced Format Technology Brief | publisher=[[Hitachi]] | format=PDF | year=2010 | page=1
| |
| | quote=512 byte emulation is sometimes referred to as 512e | accessdate=2011-08-01 }}</ref>
| |
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| [[Magneto-optical drive]]s use sector sizes of 512 and 1024 bytes on 5.25-inch drives and 512 and 2048 bytes on 3.5-inch drives.<!-- TBD: Will have to recheck if these are actually emulated on this low level: Emulated physical sector sizes of 128, 256, 512 are also seen on some computers with bootable RAM or flash disks, e.g., the [[Atari Portfolio]]. -->
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| In <code><abbr title="Cylinder">C</abbr><abbr title="Head">H</abbr><abbr title="Sector">S</abbr></code> addressing the ''sector'' numbers always start at '''1''', there is no ''sector 0'',{{citation needed|date=August 2012}}<!-- This rule is true at least for all formats where the physical sectors are named 1 upwards. However, there are a few odd floppy formats (e.g., the 640 [[Kibibyte|KiB]] format used by BBC Master 512 with DOS Plus 2.1), where the first sector in a track is named "0" not "1". So, is this rule above really universal or does it only apply to the former type of formats starting with sector "1"? --> which can lead to confusion since logical sector addressing schemes (e.g., with LBA, or with "absolute sector addressing" in DOS) typically start counting with 0.
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| For physical disk geometries the maximal sector number is determined by the ''low level format'' of the disk. However, for disk access with the [[BIOS]] of IBM-PC compatible machines, the sector number was encoded in six bits, resulting in a maximal number of <tt>63=64-1</tt> sectors per track, where <tt>64=2<sup>6</sup></tt> corresponds to six bits. The maximum '''63''' is still in use for virtual CHS geometries.
| |
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| ===Blocks and clusters===
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| The [[Unix]] communities employ the term ''block'' to refer to a sector or group of sectors. For example, the Linux [[fdisk]] utility normally displays partition table information using 1024-byte ''blocks'', but also uses the word ''sector'' to help describe a disk's size in the phrase, ''63 sectors per track''.
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| ''Clusters'' are allocation units for data on various file systems ([[File Allocation Table|FAT]], [[NTFS]], etc.), where ''data'' mainly consists of files. ''Clusters'' are not directly affected by the physical or virtual geometry of the disk, i.e., a cluster can begin at a sector near the end of a given <code><abbr title="Cylinder">C<abbr><abbr title="Head">H</abbr></code> track, and end in a sector on the physically or logically next <code><abbr title="Cylinder">C<abbr><abbr title="Head">H</abbr></code> [[#Tracks|track]].
| |
| | |
| ===Heads===
| |
| A device called a [[disk read-and-write head|head]] reads and writes data in a hard drive by manipulating the magnetic medium that composes the surface of an associated disk platter. Naturally, a platter has 2 sides and thus 2 surfaces on which data can be manipulated; usually there are 2 heads per platter, one per side. (Sometimes the term ''side'' is substituted for ''head,'' since platters might be separated from their head assemblies, as with the removable media of a ''floppy'' drive.)
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| The <code><abbr title="Cylinder">C</abbr><abbr title="Head">H</abbr><abbr title="Sector">S</abbr></code> addressing supported in IBM-PC compatible [[BIOS]]es code used eight bits for - theoretically up to 256 heads counted as head '''0''' up to '''255''' (FFh). However, a bug in all versions of MS-DOS/PC DOS up to including 7.10 will cause these operating systems to crash on boot when encountering volumes with 256 heads. Therefore, all compatible BIOSes will use mappings with up to 255 heads (00h..FEh) only, including in virtual <tt>255×63</tt> geometries.
| |
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| This historical oddity can affect the maximum disk size in old BIOS [[INT 13H|INT 13h]] code as well as old [[PC DOS]] or similar operating systems:
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| <tt>(512 bytes/sector)×(63 sectors/track)×(255 heads (tracks/cylinder) )×(1024 cylinders)=8032.5</tt> [[Mebibyte|MiB]], but actually <tt>(512 byte/sector)×256×63×1024=8064</tt> [[Mebibyte|MiB]] yields what is known as '''8 [[Gibibyte|GiB]]''' limit.<ref name="eide" /> In this context relevant definition of 8 [[Gibibyte|GiB]] = 8192 [[Mebibyte|MiB]] is another incorrect limit, because it would require CHS <tt>512×256×64</tt> with 64 sectors per track.
| |
| | |
| ''Tracks'' and ''cylinders'' are counted from 0, i.e., track 0 is the first (outer-most) track on [[floppy disk|floppy]] or other cylindrical disks. Old [[BIOS]] code supported ten bits in CHS addressing with up to 1024 cylinders (<tt>1024=2<sup>10</sup></tt>). Adding six bits for [[#Sectors|sectors]] and eight bits for [[#Heads|heads]] results in the 24 bits supported by [[INT 13H|BIOS interrupt 13h]]. Subtracting the disallowed sector number 0 in <tt>1024×256</tt> tracks corresponds to 128 [[Mebibyte|MiB]] for a sector size of 512 bytes (<tt>128 [[Mebibyte|MiB]]=1024×256×(512 byte/sector)</tt>); and <tt>8192-128=8064</tt> confirms the (roughly) '''8 [[Gibibyte|GiB]]''' limit.<ref>{{cite web
| |
| |url=http://support.microsoft.com/kb/q224526/en-us
| |
| |title=Windows NT 4.0 supports maximum of 7.8-GB system partition
| |
| |date=2007-02-23
| |
| |publisher=[[Microsoft]]
| |
| |accessdate=2011-07-30}}</ref>
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| | |
| CHS addressing starts at <code>0/0/1</code> with a maximal value <code>1023/255/63</code> for <tt>24=10+8+6</tt> bits, or <code>1023/254/63</code> for 24 bits limited to 255 [[#Heads|heads]]. CHS values used to specify the geometry of a disk have to count cylinder 0 and head 0 resulting in
| |
| a maximum (<code>1024/256/63</code> or) <code>1024/255/63</code> for 24 bits with (256 or) 255 heads. In CHS tuples specifying a geometry S actually means sectors per track, and where the (virtual) geometry still matches the capacity the disk contains <code>C×H×S</code> sectors. As larger hard disks have come into use, a cylinder has become also a logical disk structure, standardised{{Citation needed|date=July 2011}} at 16 065 sectors (<tt>16065=255×63</tt>).
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| CHS addressing with 28 bits ([[Parallel ATA#EIDE_and_ATA-2|EIDE and ATA-2]]) permits eight bits for sectors still starting at 1, i.e., sectors 1…255, four bits for heads 0…15, and sixteen bits for cylinders 0…65535.<ref>{{cite web
| |
| |url=http://www.hitachigst.com/tech/techlib.nsf/techdocs/1F70FDFFB4DE1EBB86257538007E4CFE/$file/TS5K500.B_OEMSpec_r12a.pdf
| |
| |title=5K500.B SATA OEM Specification Revision 1.2
| |
| |publisher=[[Hitachi]]
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| |date=2009-03-17
| |
| |page=51
| |
| |format=PDF
| |
| |accessdate=2011-07-29}}</ref> This results in a roughly '''128 [[Gibibyte|GiB]]''' limit; actually <tt>65536×16×255=267386880</tt> sectors corresponding to 130560 [[Mebibyte|MiB]] for a sector size of 512 bytes.<ref name="eide">{{cite web
| |
| |url=http://tldp.org/HOWTO/Large-Disk-HOWTO-4.html
| |
| |title=History of BIOS and IDE limits
| |
| |work=Large Disk HOWTO v2.5
| |
| |author=Andries Brouwer
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| |authorlink=Andries Brouwer
| |
| |date=2004-11-01
| |
| |accessdate=2011-07-30}}</ref> The <tt>28=16+4+8</tt> bits in the [[Parallel ATA#EIDE_and_ATA-2|ATA-2]] specification are also covered by [[Ralf Brown's Interrupt List]], and an old working draft of this now expired standard was published.<ref>{{cite web
| |
| |url=http://www.t13.org/Documents/UploadedDocuments/project/d0948r4c-ATA-2.pdf
| |
| |title=ATA-2
| |
| |publisher=[[INCITS]] Technical Committee T13 AT Attachment
| |
| |date=1996-03-18
| |
| |work=X3T10/0948D
| |
| |format=PDF
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| |accessdate=2011-07-30}}</ref>
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| | |
| With an old [[BIOS]] limit of 1024 cylinders and the [[Parallel ATA|ATA]] limit of 16 heads<ref>{{cite web
| |
| |url=http://www.t10.org/t13/project/d0791r4c-ATA-1.pdf
| |
| |title=ATA-1
| |
| |publisher=[[INCITS]] Technical Committee T10 SCSI Storage Interfaces
| |
| |year=1994
| |
| |work=X3T10/791D
| |
| |format=PDF
| |
| |accessdate=2011-07-30}}</ref> the combined effect was <tt>1024×16×63=1032192</tt> sectors, i.e., a '''504 [[Mebibyte|MiB]]''' limit for sector size 512. [[BIOS]] translation schemes known as <abbr title="Extended CHS">ECHS</abbr> and ''revised ECHS'' mitigated this limitation by using 128 or 240 instead of 16 heads, simultaneously reducing the numbers of cylinders and sectors to fit into <code>1024/128/63</code> (ECHS limit: 4032 [[Mebibyte|MiB]]) or <code>1024/240/63</code> (revised ECHS limit: 7560 [[Mebibyte|MiB]]) for the given total number of sectors on a disk.<ref name="eide" />
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| | |
| ==CHS to LBA mapping==
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| {{main|Logical Block Addressing#CHS conversion}}
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| CHS [[tuple]]s can be mapped onto [[Logical Block Addressing|LBA]] (Logical Block Addressing) addresses using the following formula:
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| :<math>A = ( c \cdot N_{\mathrm{heads}} + h ) \cdot N_{\mathrm{sectors}} + (s - 1) \, </math>
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| Where <math>A</math> is the LBA address, <math>N_{\mathrm{heads}}</math> is the number of heads on the disk, <math>N_{\mathrm{sectors}}</math> is the number of sectors per track, and <math>(c, h, s)</math> is the CHS address.
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| A ''Logical Sector Number<small> </small>'' formula in the [[Ecma International|ECMA]]-107<ref name="Ecma-107"/> and [[International Organization for Standardization|ISO]]/[[International Electrotechnical Commission|IEC]] 9293:1994<ref name="ISO_9293_1994">{{ cite web | url = http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=21273 | title = Information technology -- Volume and file structure of disk cartridges for information interchange | work = ISO/IEC 9293:1994 | publisher = [[International Organization for Standardization|ISO]] catalogue | year = 1994 | accessdate = 2012-01-06 }}</ref> (superseding ISO 9293:1987<ref name="ISO_9293_1987">{{ cite web | url = http://www.iso.org/iso/iso_catalogue/catalogue_ics/catalogue_detail_ics.htm?csnumber=16948 | title = Information processing -- Volume and file structure of flexible disk cartridges for information interchange | work = ISO 9293:1987 | publisher = [[International Organization for Standardization|ISO]] catalogue | year = 1987 | accessdate = 2012-01-06 }}</ref>) standards for [[File Allocation Table|FAT]] file systems matches exactly the LBA formula given above: ''Logical Block Address'' and ''Logical Sector Number'' (LSN) are synonyms.<ref name="Ecma-107"/><ref name="ISO_9293_1994"/><ref name="ISO_9293_1987"/> The formula does not use the number of cylinders, but requires the number of heads and the number of sectors per track in the disk geometry, because the same CHS tuple addresses different logical sector numbers depending on the geometry. Examples:
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| :For geometry <code>1020 16 63</code> of a disk with 1028160 sectors CHS <code>3 2 1</code> is LBA <tt> 3150=(3* 16+2)* 63</tt>
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| :For geometry <code>1008 4 255</code> of a disk with 1028160 sectors CHS <code>3 2 1</code> is LBA <tt> 3570=(3* 4+2)*255</tt>
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| :For geometry <code> 64 255 63</code> of a disk with 1028160 sectors CHS <code>3 2 1</code> is LBA <tt>48321=(3*255+2)* 63</tt>
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| :For geometry <code>2142 15 32</code> of a disk with 1028160 sectors CHS <code>3 2 1</code> is LBA <tt> 1504=(3* 15+2)* 32</tt>
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| To help visualize the sequencing of sectors into a linear LBA model, note that;
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| :The first LBA sector is sector # zero, the same sector in a CHS model is called sector # one.
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| :All the sectors of each head/track get counted before incrementing to the next head/track.
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| :All the heads/tracks of the same cylinder get counted before incrementing to the next cylinder.
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| :The outside half of a whole Hard Drive would be the first half of the drive.
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| In 2002 the [[Parallel ATA|ATA-6]] specification introduced an optional 48 bits [[Logical Block Addressing|logical block addressing]] and declared CHS addressing as obsolete, but still allowed to implement the ATA-5 translations.<ref>{{cite web
| |
| |url=http://www.t10.org/t13/project/d1410r3a-ATA-ATAPI-6.pdf
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| |title=ATA-6
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| |publisher=[[INCITS]] Technical Committee T13 ATA Storage Interface
| |
| |format=PDF
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| |quote=In standards ATA/ATAPI-5 and earlier, a CHS translation was defined. This translation is obsolete but may be
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| implemented as defined in ATA/ATAPI-5.
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| |page=22
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| |year=2002
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| |work=T13/1410D
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| |accessdate=2011-07-30}}</ref> Unsurprisingly the CHS to LBA translation formula given above also matches the last ATA-5 CHS translation. In the ATA-5 specification CHS support was mandatory for up to 16 514 064 sectors and optional for larger disks. The ATA-5 limit corresponds to CHS <code>16383 16 63</code> or equivalent disk capacities (<tt>16514064=16383×16×63=1032×254×63</tt>), and requires <tt>24=14+4+6</tt> bits (<tt>16383+1=2<sup>14</sup></tt>).<ref>{{cite web
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| |url=http://www.t10.org/t13/project/d1321r3-ATA-ATAPI-5.pdf
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| |title=ATA-5
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| |publisher=[[INCITS]] Technical Committee T13 ATA Storage Interface
| |
| |format=PDF
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| |quote=If the device’s capacity is greater than or equal to one sector and less than or equal to
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| 16,514,064 sectors, then the device shall support CHS translation.
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| |page=19
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| |year=2000
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| |work=T13/1321D
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| |accessdate=2011-07-30}}</ref>
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| ==History==
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| Earlier hard drives used in the PC, such as [[Modified Frequency Modulation|MFM]] and [[Run Length Limited|RLL]] drives, divided each cylinder into an equal number of sectors, so the CHS values matched the physical properties of the drive. A drive with a CHS tuple of <code>500 4 32</code> would have 500 tracks per side on each platter, two platters (4 heads), and 32 sectors per track, with a total of 32 768 000 [[bytes]] (31.25 [[Mebibyte|MiB]]).
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| [[Advanced Technology Attachment|ATA/IDE]] drives were much more efficient at storing data and have replaced the now ''archaic'' MFM and RLL drives. They use [[zone bit recording]] (ZBR), where the number of sectors dividing each track varies with the location of groups of tracks on the surface of the platter. Tracks nearer to the edge of the platter contain more blocks of data than tracks close to the spindle, because there is more physical space within a given track near the edge of the platter. Thus, the CHS addressing scheme cannot correspond directly with the physical geometry of such drives, due to the varying number of sectors per track for different regions on a platter. Because of this, many drives still have a surplus of sectors (less than 1 cylinder in size) at the end of the drive, since the total number of sectors rarely, if ever, ends on a cylinder boundary.
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| An ATA/IDE drive can be set in the system [[BIOS]] with any configuration of cylinders, heads and sectors that do not exceed the capacity of the drive (or the BIOS), since the drive will convert any given CHS value into an actual address for its specific hardware configuration. This however can cause compatibility problems.
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| For operating systems such as [[Microsoft]] [[DOS]] or older version of [[Microsoft Windows|Windows]], each partition must start and end at a cylinder boundary. Only some of the most modern [[operating system]]s (Windows XP included) may disregard this rule, but doing so can still cause some compatibility issues, especially if the user wants to perform [[dual boot]]ing on the same drive. Microsoft does not follow this rule with internal disk partition tools since Windows Vista.<ref>{{cite web
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| |url=http://support.microsoft.com/kb/931760/en-us
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| |title=KB931760
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| |work=Microsoft Windows XP Support
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| |date=2009-07-23
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| |publisher=[[Microsoft Knowledge Base]]
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| |accessdate=2011-07-30}}</ref>
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| ==See also==
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| * [[Cylinder (disk drive)]]
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| * [[CD-ROM#CD-ROM format|CD-ROM format]]
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| * [[Block (data storage)]]
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| * [[Disk storage]]
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| * [[Disk formatting]]
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| * [[File Allocation Table]]
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| * [[Disk partitioning]]
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| ==References==
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| <references /> | |
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| ==External links==
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| * [http://myweb.tiscali.co.uk/bridip/recovery.htm Hard Disk backup, repair, and data recovery]
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| {{Use dmy dates|date=July 2011}}
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| {{DEFAULTSORT:Cylinder-Head-Sector}}
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| [[Category:AT Attachment]]
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| [[Category:BIOS]]
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| [[Category:Computer file systems]]
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| [[Category:Hard disk computer storage]]
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| [[Category:Rotating disc computer storage media]]
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| [[Category:Computer storage devices]]
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| [[Category:IBM storage devices]]
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