582:(the number of bits that can be stored in a certain area of the disk) has been increased over time by increasing both the number of tracks across the disk, and the number of sectors per track. The latter will increase the data transfer rate for a given RPM speed. Improvement of data transfer rate performance is correlated to the areal density only by increasing a track's linear surface bit density (sectors per track). Simply increasing the number of tracks on a disk can affect seek times but not gross transfer rates. According to industry observers and analysts for 2011 to 2016, “The current roadmap predicts no more than a 20%/yr improvement in bit density”. Seek times have not kept up with throughput increases, which themselves have not kept up with growth in bit density and storage capacity.
121:) and there is an actuator with an arm that suspends a head that can transfer data with that media. When the drive needs to read or write a certain sector it determines in which track the sector is located. It then uses the actuator to move the head to that particular track. If the initial location of the head was the desired track then the seek time would be zero. If the initial track was the outermost edge of the media and the desired track was at the innermost edge then the seek time would be the maximum for that drive. Seek times are not linear compared with the seek distance traveled because of factors of acceleration and deceleration of the actuator arm.
637:
destination only just in time to read the sector, rather than arriving as quickly as possible and then having to wait for the sector to come around (i.e. the rotational latency). Many of the hard drive companies are now producing Green Drives that require much less power and cooling. Many of these Green Drives spin slower (<5,400 rpm compared to 7,200, 10,000 or 15,000 rpm) thereby generating less heat. Power consumption can also be reduced by parking the drive heads when the disk is not in use reducing friction, adjusting spin speeds, and disabling internal components when not in use.
458:
591:
701:
48:
735:(SMR) differ significantly in write performance characteristics from conventional (CMR) drives. In particular, sustained random writes are significantly slower on SMR drives. As SMR technology causes a degradation on write performance, some new HDD with Hybrid SMR technology (making it possible to adjust the ratio of SMR part and CMR part dynamically) may have various characteristics under different SMR/CMR ratios.
398:). Most hard disk drives today support some form of power management which uses a number of specific power modes that save energy by reducing performance. When implemented, an HDD will change between a full power mode to one or more power saving modes as a function of drive usage. Recovery from the deepest mode, typically called Sleep where the drive is stopped or
163:. The track-to-track measurement is the time required to move from one track to an adjacent track. This is the shortest (fastest) possible seek time. In HDDs this is typically between 0.2 and 0.8 ms. The full stroke measurement is the time required to move from the outermost track to the innermost track. This is the longest (slowest) possible seek time.
520:" data transfer rate up to 1030 Mbit/s. This rate depends on the track location, so it will be higher on the outer zones (where there are more data sectors per track) and lower on the inner zones (where there are fewer data sectors per track); and is generally somewhat higher for 10,000 RPM drives.
627:
has become increasingly important, not only in mobile devices such as laptops but also in server and desktop markets. Increasing data center machine density has led to problems delivering sufficient power to devices (especially for spin up), and getting rid of the waste heat subsequently produced, as
608:
Sector interleave is a mostly obsolete device characteristic related to data rate, dating back to when computers were too slow to be able to read large continuous streams of data. Interleaving introduced gaps between data sectors to allow time for slow equipment to get ready to read the next block of
481:
of a drive will be the lower of the sustained internal and sustained external rates. The sustained rate is less than or equal to the maximum or burst rate because it does not have the benefit of any cache or buffer memory in the drive. The internal rate is further determined by the media rate, sector
373:
Another wrinkle occurs depending on whether surface bit densities are constant. Usually, with a CAV spin rate, the densities are not constant so that the long outside tracks have the same number of bits as the shorter inside tracks. When the bit density is constant, outside tracks have more bits than
214:
offers a set of features in some drives called Sound
Barrier Technology that include some user or system controlled noise and vibration reduction capability. Shorter seek times typically require more energy usage to quickly move the heads across the platter, causing loud noises from the pivot bearing
766:
that are smaller (2K, 4K, 8K, or 16K) than the blocks of data managed by the SSD (from 256 KB to 4 MB, hence 128 to 256 pages per block), over time, an SSD's write performance can degrade as the drive becomes full of pages which are partial or no longer needed by the file system. This can
174:
is a term used in enterprise storage environments to describe an HDD that is purposely restricted in total capacity so that the actuator only has to move the heads across a smaller number of total tracks. This limits the maximum distance the heads can be from any point on the drive thereby reducing
566:
is a procedure used to minimize delay in retrieving data by moving related items to physically proximate areas on the disk. Some computer operating systems perform defragmentation automatically. Although automatic defragmentation is intended to reduce access delays, the procedure can slow response
612:
However, because interleaving introduces intentional physical delays between blocks of data thereby lowering the data rate, setting the interleave to a ratio higher than required causes unnecessary delays for equipment that has the performance needed to read sectors more quickly. The interleaving
507:
Additional time required to move to the first track of the next cylinder and begin reading; the name cylinder is used because typically all the tracks of a drive with more than one head or data surface are read before moving the actuator. This time is typically about twice the track-to-track seek
671:
Most hard disk drives today support some form of power management which uses a number of specific power modes that save energy by reducing performance. When implemented an HDD will change between a full power mode to one or more power saving modes as a function of drive usage. Recovery from the
636:
increase at higher drive temperatures. Similar issues exist for large companies with thousands of desktop PCs. Smaller form factor drives often use less power than larger drives. One interesting development in this area is actively controlling the seek speed so that the head arrives at its
640:
Drives use more power, briefly, when starting up (spin-up). Although this has little direct effect on total energy consumption, the maximum power demanded from the power supply, and hence its required rating, can be reduced in systems with several drives by controlling when they spin up.
71:. It is composed of a few independently measurable elements that are added together to get a single value when evaluating the performance of a storage device. The access time can vary significantly, so it is typically provided by manufacturers or measured in benchmarks as an average.
128:
is the average of all possible seek times which technically is the time to do all possible seeks divided by the number of all possible seeks, but in practice it is determined by statistical methods or simply approximated as the time of a seek over one-third of the number of tracks.
473:) covers both the internal rate (moving data between the disk surface and the controller on the drive) and the external rate (moving data between the controller on the drive and the host system). The measurable data transfer rate will be the lower (slower) of the two rates. The
894:
546:
A current widely used standard for the "buffer-to-computer" interface is 3.0 Gbit/s SATA, which can send about 300 megabyte/s (10-bit encoding) from the buffer to the computer, and thus is still comfortably ahead of today's disk-to-buffer transfer rates.
215:
and greater device vibrations as the heads are rapidly accelerated during the start of the seek motion and decelerated at the end of the seek motion. Quiet operation reduces movement speed and acceleration rates, but at a cost of reduced seek performance.
348:
Therefore, the rotational latency and resulting access time can be improved (decreased) by increasing the rotational speed of the disks. This also has the benefit of improving (increasing) the throughput (discussed later in this article).
575:
HDD data transfer rate depends upon the rotational speed of the disks and the data recording density. Because heat and vibration limit rotational speed, increasing density has become the main method to improve sequential transfer rates.
385:
has become increasingly important, not only in mobile devices such as laptops but also in server and desktop markets. Increasing data center machine density has led to problems delivering sufficient power to devices (especially for
108:
measures the time it takes the head assembly on the actuator arm to travel to the track of the disk where the data will be read or written. The data on the media is stored in sectors which are arranged in parallel circular tracks
374:
inside tracks and is generally combined with a CLV spin rate. In both these schemes contiguous bit transfer rates are constant. This is not the case with other schemes such as using constant bit density with a CAV spin rate.
609:
data. Without interleaving, the next logical sector would arrive at the read/write head before the equipment was ready, requiring the system to wait for another complete disk revolution before reading could be performed.
660:(PUIS): each drive does not spin up until the controller or system BIOS issues a specific command to do so. This allows the system to be set up to stagger disk start-up and limit maximum power demand at switch-on.
759:
Measurement of seek time is only testing electronic circuits preparing a particular location on the memory in the storage device. Typical SSDs will have a seek time between 0.08 and 0.16 ms.
426:
is the time it takes for the drive electronics to set up the necessary communication between the various components in the device so it can read or write the data. This is of the order of 3
501:
Additional time required to electrically switch from one head to another, re-align the head with the track and begin reading; only applies to multi-head drive and is about 1 to 2 ms.
684:
that parks the disk heads if the machine is dropped, hopefully before impact, to offer the greatest possible chance of survival in such an event. Maximum shock tolerance to date is 350
495:
Additional time (bytes between sectors) needed for control structures and other information necessary to manage the drive, locate and validate data and perform other support functions.
406:
that include some additional features that do reduce power, but can adversely affect the latency including lower spindle speeds and parking heads off the media to reduce friction.
1380:
In some early PCs the internal bus was slower than the drive data rate so sectors would be missed resulting in the loss of an entire revolution. To prevent this sectors were
613:
ratio was therefore usually chosen by the end-user to suit their particular computer system's performance capabilities when the drive was first installed in their system.
137:
The first HDD had an average seek time of about 600 ms. and by the middle 1970s, HDDs were available with seek times of about 25 ms. Some early PC drives used a
152:. Some mobile devices have 15 ms drives, with the most common mobile drives at about 12 ms and the most common desktop drives typically being around 9 ms.
550:
SSDs do not have the same internal limits of HDDs, so their internal and external transfer rates are often maximizing the capabilities of the drive-to-host interface.
1923:
1437:
844:
516:
According to vendor specifications sustained transfer rates up to 204 MB/s are available. As of 2010, a typical 7,200 RPM desktop HDD has a "disk-to-
657:
1606:
402:, may take as long as several seconds to be fully operational thereby increasing the resulting latency. The drive manufacturers are also now producing
756:
are not applicable in measuring their performance, but they are affected by some electrically based elements that causes a measurable access delay.
1781:
1570:
1215:
1132:
1106:
1081:
775:. Flash memory wears out over time as it is repeatedly written to; the writes required by defragmentation wear the drive for no speed advantage.
512:
Data transfer rate (read/write) can be measured by writing a large file to disk using special file generator tools, then reading back the file.
1822:
1544:
1463:
449:. This time is usually very small, typically less than 100 ÎĽs, and modern HDD manufacturers account for it in their seek time specifications.
1489:
869:
175:
its average seek time, but also restricts the total capacity of the drive. This reduced seek time enables the HDD to increase the number of
207:) to reduce audible clicks and crunching sounds. Drives in smaller form factors (e.g. 2.5 inch) are often quieter than larger drives.
1337:
977:
616:
Modern technology is capable of reading data as fast as it can be obtained from the spinning platters, so interleaving is no longer used.
315:
is typically based on the empirical relation that the average latency in milliseconds for such a drive is one-half the rotational period.
1312:
1158:
928:
31:
comes from devices which have better performance characteristics. These performance characteristics can be grouped into two categories:
362:(CLV), used mainly in optical storage, varies the rotational speed of the optical disc depending upon the position of the head, and 2)
1806:
67:. The factors that control this time on a rotating drive are mostly related to the mechanical nature of the rotating disks and moving
1515:
210:
Some desktop- and laptop-class disk drives allow the user to make a trade-off between seek performance and drive noise. For example,
818:
1661:
712:
1763:
1183:
1707:
1865:
1295:
145:
type actuation in the 1980s, reducing seek times to around 20 ms. Seek time has continued to improve slowly over time.
1920:
1441:
1384:
to slow the effective data rate preventing missed sectors. This is no longer a problem for current PCs and storage devices.
1594:
2007:
744:
1940:
1395:
1050:
2077:
179:
available from the drive. The cost and power per usable byte of storage rises as the maximum track range is reduced.
2033:
578:
1754:
1614:
141:
to move the heads, and as a result had seek times as slow as 80–120 ms, but this was quickly improved by
2087:
204:
1003:
1966:
681:
667:, allowing the computer to spin up the drives in sequence to reduce load on the power supply when booting.
1381:
732:
1789:
1574:
1136:
1026:
685:
645:
On SCSI hard disk drives, the SCSI controller can directly control spin up and spin down of the drives.
1764:
UNESCO International
Conference, Memory of the World in the Digital Age: Digitization and Preservation
1110:
1085:
2082:
559:
363:
17:
1244:
1826:
1548:
1263:
772:
359:
68:
2047:
1885:
1686:
430:, very much less than other overhead times, so it is usually ignored when benchmarking hardware.
323:
time (as the relevant part of the disk may have just passed the head when the request arrived).
1899:
1857:
1467:
1416:
1344:
308:
192:
1285:
932:
1493:
873:
457:
1803:
1753:
Rosenthal, David S.H.; Rosenthal, Daniel C.; Miller, Ethan L.; Adams, Ian F. (2012-09-28).
981:
799:
1316:
594:
Low-level formatting software from 1987 to find highest performance interleave choice for
8:
763:
304:
203:, lower rotational speeds (usually 5,400 rpm) and reduce the seek speed under load (
1729:
590:
1850:
1610:
1595:
https://www.seagate.com/files/docs/pdf/datasheet/disc/cheetah-15k.7-ds1677.3-1007us.pdf
953:
211:
1981:
1519:
1191:
680:
Shock resistance is especially important for mobile devices. Some laptops now include
534:" data transfer rates varies amongst families of Optical disk drives with the slowest
527:" data transfer rates that are one or two orders of magnitude lower than that of HDDs.
1960:
1861:
1291:
753:
749:
624:
382:
367:
64:
370:, spins the media at one constant speed regardless of where the head is positioned.
74:
The key components that are typically added together to obtain the access time are:
63:
of a rotating drive is a measure of the time it takes before the drive can actually
768:
762:
Flash memory-based SSDs do not need defragmentation. However, because file systems
664:
632:). Heat dissipation is tied directly to power consumption, and as drives age, disk
353:
118:
819:"Hard Disk (Hard Drive) Performance – transfer rates, latency and seek times"
394:
subsequently produced, as well as environmental and electrical cost concerns (see
1927:
1810:
1222:
1187:
629:
563:
539:
395:
28:
1057:
2011:
535:
358:
The spindle motor speed can use one of two types of disk rotation methods: 1)
2071:
200:
138:
1159:"Western Digital's New VelociRaptor VR200M: 10K RPM at 450GB and 600GB"
752:(SSDs) do not have moving parts. Most attributes related to the movement of
303:
under the read-write head. It depends on the rotational speed of a disk (or
1636:
789:
672:
deepest mode, typically called Sleep, may take as long as several seconds.
649:
633:
1823:"Hitachi Unveils Energy-Efficient Hard Drive with Variable Spindle Speed"
1710:(Press release). IHSi iSuppli Research. storagenewsletter.com. 2012-05-24
1368:
531:
524:
517:
427:
300:
188:
149:
700:
148:
The fastest high-end server drives today have a seek time around 4
653:
391:
142:
110:
1782:"Hard Disk Drive Power Consumption Measurements: X-bit's Methodology"
47:
489:
Rate at which the drive can read bits from the surface of the media.
445:
on the target track and stop vibrating so they do not read or write
366:(CAV), used in HDDs, standard FDDs, a few optical disc systems, and
597:
296:
196:
399:
387:
320:
191:, audible noise is significant for certain applications, such as
182:
51:
A hard disk head on an access arm resting on a hard disk platter
845:"Red Hat Documentation: Hard Drive Performance Characteristics"
114:
1941:"Surreptitiously Swapping SMR into Hard Drive Lines Must Stop"
1852:
Green tech: how to plan and implement sustainable IT solutions
1752:
1367:
In the 1950s and 1960s magnetic data storage devices used a
1216:"Understanding Solid State Drives (part two – performance)"
794:
784:
745:
Solid-state drive § Comparison with other technologies
482:
overhead time, head switch time, and cylinder switch time.
176:
2008:"To Defrag or Not to Defrag–That Is the Question for SSD"
1024:
538:
at 1.23 Mbit/s floppy-like while a high performance
319:
is the time it takes to do a full rotation excluding any
155:
Two other less commonly referenced seek measurements are
1886:"Hitachi Deskstar 7K500 500GB HDD: As fast as it's big?"
1287:
The
Essentials of Computer Organization and Architecture
628:
well as environmental and electrical cost concerns (see
1662:"Turning Off Disk Defragmenter May Solve a Sluggish PC"
1538:
1536:
542:
at 432 Mbit/s approaches the performance of HDDs.
461:
A plot showing dependency of transfer rate on cylinder
377:
1176:
663:
Some SATA II and later hard disk drives support
1533:
1133:"IBM Archives – IBM 3350 direct access storage"
1562:
1290:. Jones & Bartlett Learning. pp. 499–500.
738:
132:
1900:"Adaptive Power Management for Mobile Hard Drives"
1849:
1721:
1628:
1417:"Adaptive Power Management for Mobile Hard Drives"
1018:
1730:"HDD Opportunities & Challenges, Now to 2020"
1455:
954:"What is Seek Time? - Definition from Techopedia"
863:
861:
311:(RPM). For most magnetic media-based drives, the
2069:
1156:
1883:
1825:. Xbitlabs.com. 22 October 2007. Archived from
1773:
1481:
1082:"IBM Archives – IBM 350 disk storage unit"
971:
969:
967:
1678:
1507:
1438:"Momentus 5400.5 SATA 3Gb/s 320-GB Hard Drive"
1304:
1284:Null, Linda; Lobur, Julia (14 February 2014).
1264:"Accelerate Your Hard Drive By Short Stroking"
1245:"Accelerate Your Hard Drive By Short Stroking"
1184:"WD Scorpio Blue Mobile: Drive Specifications"
923:
921:
919:
917:
915:
913:
911:
858:
508:time. As of 2001, it was about 2 to 3 ms.
1847:
1746:
1727:
1277:
995:
688:for operating and 1,000 g for non-operating.
567:when performed while the computer is in use.
183:Effect of audible noise and vibration control
1921:Momentus 5400.5 SATA 3Gb/s 320-GB Hard Drive
964:
88:
1848:Webber, Lawrence; Wallace, Michael (2009).
1700:
1262:Schmid, Patrick; Roos, Achim (2009-03-05).
908:
523:Floppy disk drives have sustained "disk-to-
1947:. The 2-minute SMR and Industry Background
1756:The Economics of Long-Term Digital Storage
1708:"HDD Areal Density Doubling in Five Years"
1387:
1261:
1025:Chris Ruemmler; John Wilkes (March 1994).
811:
570:
2040:
1914:
1892:
1877:
1841:
1815:
1796:
1779:
1653:
1599:
1430:
1283:
1210:
1208:
1107:"IBM Archives: IBM 350 disk storage unit"
1004:"Hard Disk Tracks, Cylinders and Sectors"
1999:
1684:
1568:
1542:
1513:
1487:
1461:
1409:
1374:
1361:
1330:
1310:
1255:
1125:
1074:
1043:
1027:"An introduction to disk drive modeling"
1001:
975:
931:. New York Data Recovery. Archived from
867:
839:
837:
835:
589:
553:
456:
46:
1979:
1938:
887:
83:
36:
14:
2070:
1659:
1634:
1205:
1135:. IBM. 23 January 2003. Archived from
1099:
1084:. IBM. 23 January 2003. Archived from
1516:"Transfer Performance Specifications"
1002:Kozierok, Charles (18 January 2019).
832:
452:
218:
1393:
1338:"Seagate's Sound Barrier Technology"
771:command from the system or internal
695:
619:
2005:
1780:Artamonov, Oleg (6 December 2007).
1396:"Calculate IOPS in a storage array"
929:"Hard Drive Data Recovery Glossary"
675:
558:Transfer rate can be influenced by
378:Effect of reduced power consumption
24:
1884:Trusted Reviews (31 August 2005).
1157:Anand Lal Shimpi (April 6, 2010).
441:is the time it takes the heads to
299:of the disk to bring the required
25:
2099:
2034:"How do SSDS Work? - ExtremeTech"
2010:. rtcmagazine.com. Archived from
1109:. 23 January 2003. Archived from
1051:"Definition of Average Seek time"
166:
1685:Kozierok, Charles (2001-04-17).
1569:Kozierok, Charles (2001-04-17).
1543:Kozierok, Charles (2001-04-17).
1514:Kozierok, Charles (2001-04-17).
1488:Kozierok, Charles (2001-04-17).
1462:Kozierok, Charles (2001-04-17).
1311:Kozierok, Charles (2001-04-17).
976:Kozierok, Charles (2001-04-17).
868:Kozierok, Charles (2001-04-17).
739:Comparison to solid-state drives
699:
656:(SATA) hard disk drives support
199:. Low noise disks typically use
133:Seek times & characteristics
93:
32:
2026:
2006:Lee, Yu Hsuan (December 2008).
1980:Brendan, Collins (2017-11-13).
1973:
1939:Kennedy, Patrick (2020-04-26).
1932:
1588:
1343:. November 2000. Archived from
1237:
1150:
295:) is the delay waiting for the
1032:. Hewlett-Packard Laboratories
946:
195:, digital audio recording and
78:
42:
13:
1:
1573:. pcguide.com. Archived from
1547:. pcguide.com. Archived from
1518:. pcguide.com. Archived from
1492:. pcguide.com. Archived from
1466:. pcguide.com. Archived from
1315:. pcguide.com. Archived from
980:. pcguide.com. Archived from
872:. pcguide.com. Archived from
805:
691:
585:
562:and the layout of the files.
2048:"Sustaining SSD Performance"
682:active hard drive protection
475:sustained data transfer rate
99:
37:data transfer time (or rate)
7:
1769:. UNESCO. pp. 513–528.
1660:Broida, Rick (2009-04-10).
1635:Kearns, Dave (2001-04-18).
1190:. June 2010. Archived from
778:
733:shingled magnetic recording
354:Disk storage § CAV-CLV
273:
265:
257:
249:
241:
10:
2104:
1394:Lowe, Scott (2010-02-12).
895:"Getting the hang of IOPS"
742:
390:), and getting rid of the
351:
317:Maximum rotational latency
313:average rotational latency
104:With rotating drives, the
560:file system fragmentation
364:constant angular velocity
2078:Computer storage devices
1965:: CS1 maint: location (
469:of a drive (also called
409:
360:constant linear velocity
1802:e.g. Western Digital's
1464:"Command Overhead Time"
571:Effect of areal density
530:The sustained "disk-to-
418:command processing time
89:Command processing time
1728:Dave Anderson (2013).
1607:"Speed Considerations"
1571:"Cylinder switch Time"
1371:instead of flat discs.
605:
462:
309:revolutions per minute
52:
27:Higher performance in
1313:"Noise and Vibration"
754:mechanical components
731:Hard drives that use
593:
554:Effect of file system
460:
352:Further information:
343:= 0.5*Maximum latency
50:
2088:Computer peripherals
1982:"Dynamic Hybrid SMR"
1617:on 20 September 2011
800:Standard RAID levels
767:be ameliorated by a
504:Cylinder switch time
492:Sector overhead time
479:sustained throughput
224:Typical HDD figures
1986:WesternDigital BLOG
1792:on 16 October 2012.
1139:on January 21, 2005
764:write pages of data
750:Solid-state devices
658:power-up in standby
368:vinyl audio records
225:
124:A rotating drive's
117:depending upon the
1926:2010-11-29 at the
1856:. AMACOM. p.
1809:2012-11-18 at the
1545:"Head switch Time"
1398:. techrepublic.com
1266:. tomshardware.com
1225:. October 27, 2008
773:garbage collection
711:. You can help by
606:
467:data transfer rate
463:
453:Data transfer rate
287:(sometimes called
285:Rotational latency
223:
219:Rotational latency
84:Rotational latency
53:
2014:on April 24, 2011
1902:. Almaden.ibm.com
1872:green disk drive.
1867:978-0-8144-1446-0
1829:on 17 August 2012
1786:Xbit Laboratories
1297:978-1-284-15077-3
821:. pctechguide.com
729:
728:
665:staggered spin-up
625:Power consumption
620:Power consumption
540:12x Blu-ray drive
383:Power consumption
282:
281:
126:average seek time
16:(Redirected from
2095:
2083:Hard disk drives
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1794:
1793:
1788:. Archived from
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1623:
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1613:. Archived from
1603:
1597:
1592:
1586:
1585:
1583:
1582:
1566:
1560:
1559:
1557:
1556:
1540:
1531:
1530:
1528:
1527:
1511:
1505:
1504:
1502:
1501:
1485:
1479:
1478:
1476:
1475:
1459:
1453:
1452:
1450:
1449:
1440:. Archived from
1434:
1428:
1427:
1425:
1424:
1413:
1407:
1406:
1404:
1403:
1391:
1385:
1378:
1372:
1365:
1359:
1358:
1356:
1355:
1349:
1342:
1334:
1328:
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1325:
1324:
1308:
1302:
1301:
1281:
1275:
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1259:
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1241:
1235:
1234:
1232:
1230:
1220:
1212:
1203:
1202:
1200:
1199:
1180:
1174:
1173:
1171:
1169:
1154:
1148:
1147:
1145:
1144:
1129:
1123:
1122:
1120:
1118:
1113:on April 9, 2005
1103:
1097:
1096:
1094:
1093:
1088:on April 9, 2005
1078:
1072:
1071:
1069:
1068:
1062:
1056:. Archived from
1055:
1047:
1041:
1040:
1038:
1037:
1031:
1022:
1016:
1015:
1013:
1011:
999:
993:
992:
990:
989:
973:
962:
961:
950:
944:
943:
941:
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925:
906:
905:
903:
902:
891:
885:
884:
882:
881:
865:
856:
855:
853:
852:
841:
830:
829:
827:
826:
815:
724:
721:
703:
696:
676:Shock resistance
603:
600:
498:Head switch time
439:
438:
424:command overhead
420:
419:
289:rotational delay
226:
222:
29:hard disk drives
21:
2103:
2102:
2098:
2097:
2096:
2094:
2093:
2092:
2068:
2067:
2066:
2056:
2054:
2050:
2046:
2045:
2041:
2032:
2031:
2027:
2017:
2015:
2004:
2000:
1990:
1988:
1978:
1974:
1958:
1957:
1950:
1948:
1937:
1933:
1928:Wayback Machine
1919:
1915:
1905:
1903:
1898:
1897:
1893:
1882:
1878:
1868:
1846:
1842:
1832:
1830:
1821:
1820:
1816:
1811:Wayback Machine
1801:
1797:
1778:
1774:
1766:
1759:
1751:
1747:
1738:
1736:
1732:
1726:
1722:
1713:
1711:
1706:
1705:
1701:
1692:
1690:
1687:"Areal Density"
1683:
1679:
1670:
1668:
1658:
1654:
1645:
1643:
1637:"How to defrag"
1633:
1629:
1620:
1618:
1605:
1604:
1600:
1593:
1589:
1580:
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1322:
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1309:
1305:
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1282:
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1269:
1267:
1260:
1256:
1251:. 5 March 2009.
1243:
1242:
1238:
1228:
1226:
1218:
1214:
1213:
1206:
1197:
1195:
1188:Western Digital
1182:
1181:
1177:
1167:
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1126:
1116:
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1029:
1023:
1019:
1009:
1007:
1000:
996:
987:
985:
974:
965:
952:
951:
947:
938:
936:
927:
926:
909:
900:
898:
893:
892:
888:
879:
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866:
859:
850:
848:
843:
842:
833:
824:
822:
817:
816:
812:
808:
781:
747:
741:
725:
719:
716:
709:needs expansion
694:
678:
630:green computing
622:
604:hard disk drive
601:
595:
588:
573:
564:Defragmentation
556:
455:
436:
435:
417:
416:
412:
396:green computing
380:
356:
339:Average latency
329:Maximum latency
307:), measured in
237:
235:
230:
221:
197:quiet computers
185:
169:
135:
102:
45:
23:
22:
15:
12:
11:
5:
2101:
2091:
2090:
2085:
2080:
2065:
2064:
2039:
2025:
1998:
1972:
1931:
1913:
1891:
1876:
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1814:
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1386:
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1303:
1296:
1276:
1254:
1249:Tom's Hardware
1236:
1204:
1175:
1149:
1124:
1098:
1073:
1042:
1017:
1006:. The PC Guide
994:
963:
958:Techopedia.com
945:
907:
886:
857:
831:
809:
807:
804:
803:
802:
797:
792:
787:
780:
777:
743:Main article:
740:
737:
727:
726:
706:
704:
693:
690:
677:
674:
669:
668:
661:
646:
621:
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587:
584:
572:
569:
555:
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543:
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510:
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496:
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454:
451:
411:
408:
379:
376:
346:
345:
335:
280:
279:
276:
272:
271:
268:
264:
263:
260:
256:
255:
252:
248:
247:
244:
240:
239:
232:
220:
217:
201:fluid bearings
184:
181:
172:Short stroking
168:
167:Short stroking
165:
157:track-to-track
134:
131:
101:
98:
97:
96:
91:
86:
81:
44:
41:
9:
6:
4:
3:
2:
2100:
2089:
2086:
2084:
2081:
2079:
2076:
2075:
2073:
2049:
2043:
2035:
2029:
2013:
2009:
2002:
1987:
1983:
1976:
1968:
1962:
1946:
1942:
1935:
1929:
1925:
1922:
1917:
1901:
1895:
1887:
1880:
1873:
1869:
1863:
1859:
1854:
1853:
1844:
1828:
1824:
1818:
1812:
1808:
1805:
1799:
1791:
1787:
1783:
1776:
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1758:
1757:
1749:
1731:
1724:
1709:
1703:
1689:. pcguide.com
1688:
1681:
1667:
1663:
1656:
1642:
1638:
1631:
1616:
1612:
1608:
1602:
1596:
1591:
1577:on 2013-03-14
1576:
1572:
1565:
1551:on 2013-03-14
1550:
1546:
1539:
1537:
1522:on 2012-03-20
1521:
1517:
1510:
1496:on 2012-01-08
1495:
1491:
1490:"Settle Time"
1484:
1470:on 2012-04-19
1469:
1465:
1458:
1444:on 2010-11-29
1443:
1439:
1433:
1418:
1412:
1397:
1390:
1383:
1377:
1370:
1364:
1350:on 2012-03-24
1346:
1339:
1333:
1319:on 2012-01-01
1318:
1314:
1307:
1299:
1293:
1289:
1288:
1280:
1265:
1258:
1250:
1246:
1240:
1224:
1217:
1211:
1209:
1194:on 2011-01-05
1193:
1189:
1185:
1179:
1164:
1163:anandtech.com
1160:
1153:
1138:
1134:
1128:
1112:
1108:
1102:
1087:
1083:
1077:
1063:on 2010-12-17
1059:
1052:
1046:
1028:
1021:
1005:
998:
984:on 2012-04-19
983:
979:
972:
970:
968:
959:
955:
949:
935:on 2011-07-15
934:
930:
924:
922:
920:
918:
916:
914:
912:
896:
890:
876:on 2012-03-19
875:
871:
870:"Access Time"
864:
862:
846:
840:
838:
836:
820:
814:
810:
801:
798:
796:
793:
791:
788:
786:
783:
782:
776:
774:
770:
765:
760:
757:
755:
751:
746:
736:
734:
723:
720:November 2020
714:
710:
707:This section
705:
702:
698:
697:
689:
687:
683:
673:
666:
662:
659:
655:
651:
647:
644:
643:
642:
638:
635:
634:failure rates
631:
626:
617:
614:
610:
599:
592:
583:
581:
580:
579:Areal density
568:
565:
561:
551:
548:
541:
537:
533:
529:
526:
522:
519:
515:
514:
513:
506:
503:
500:
497:
494:
491:
488:
485:
484:
483:
480:
476:
472:
468:
459:
450:
448:
444:
440:
431:
429:
425:
421:
407:
405:
401:
397:
393:
389:
384:
375:
371:
369:
365:
361:
355:
350:
344:
341:
340:
336:
334:
331:
330:
326:
325:
324:
322:
318:
314:
310:
306:
305:spindle motor
302:
298:
294:
290:
286:
277:
274:
269:
266:
261:
258:
253:
250:
245:
242:
233:
228:
227:
216:
213:
208:
206:
202:
198:
194:
190:
180:
178:
173:
164:
162:
158:
153:
151:
146:
144:
140:
139:stepper motor
130:
127:
122:
120:
116:
112:
107:
95:
92:
90:
87:
85:
82:
80:
77:
76:
75:
72:
70:
66:
65:transfer data
62:
61:response time
58:
49:
40:
38:
34:
30:
19:
2055:. Retrieved
2042:
2028:
2016:. Retrieved
2012:the original
2001:
1989:. Retrieved
1985:
1975:
1949:. Retrieved
1945:ServeTheHome
1944:
1934:
1916:
1904:. Retrieved
1894:
1879:
1871:
1851:
1843:
1831:. Retrieved
1827:the original
1817:
1798:
1790:the original
1785:
1775:
1755:
1748:
1737:. Retrieved
1723:
1712:. Retrieved
1702:
1691:. Retrieved
1680:
1669:. Retrieved
1665:
1655:
1644:. Retrieved
1640:
1630:
1619:. Retrieved
1615:the original
1601:
1590:
1579:. Retrieved
1575:the original
1564:
1553:. Retrieved
1549:the original
1524:. Retrieved
1520:the original
1509:
1498:. Retrieved
1494:the original
1483:
1472:. Retrieved
1468:the original
1457:
1446:. Retrieved
1442:the original
1432:
1421:. Retrieved
1411:
1400:. Retrieved
1389:
1376:
1363:
1352:. Retrieved
1345:the original
1332:
1321:. Retrieved
1317:the original
1306:
1286:
1279:
1268:. Retrieved
1257:
1248:
1239:
1227:. Retrieved
1196:. Retrieved
1192:the original
1178:
1168:December 19,
1166:. Retrieved
1162:
1152:
1141:. Retrieved
1137:the original
1127:
1115:. Retrieved
1111:the original
1101:
1090:. Retrieved
1086:the original
1076:
1065:. Retrieved
1058:the original
1045:
1034:. Retrieved
1020:
1008:. Retrieved
997:
986:. Retrieved
982:the original
957:
948:
937:. Retrieved
933:the original
899:. Retrieved
897:. 2011-04-25
889:
878:. Retrieved
874:the original
849:. Retrieved
847:. redhat.com
823:. Retrieved
813:
790:Hybrid drive
761:
758:
748:
730:
717:
713:adding to it
708:
679:
670:
650:Parallel ATA
639:
623:
615:
611:
607:
577:
574:
557:
549:
545:
511:
478:
474:
470:
466:
464:
446:
442:
434:
432:
423:
415:
413:
404:green drives
403:
381:
372:
357:
347:
342:
338:
337:
332:
328:
327:
316:
312:
292:
288:
284:
283:
209:
187:Measured in
186:
171:
170:
160:
156:
154:
147:
136:
125:
123:
105:
103:
73:
60:
56:
54:
26:
1991:15 February
1804:Intelliseek
1382:interleaved
1117:October 19,
978:"Seek Time"
652:(PATA) and
437:settle time
301:disk sector
229:HDD spindle
161:full stroke
119:device type
94:Settle time
57:access time
43:Access time
33:access time
2072:Categories
1951:6 November
1739:2014-05-23
1714:2014-05-31
1693:2012-04-04
1671:2011-07-03
1646:2011-07-03
1621:2013-12-02
1581:2012-04-04
1555:2012-04-04
1526:2012-04-04
1500:2012-04-04
1474:2012-04-04
1448:2011-07-06
1423:2011-07-06
1402:2011-07-03
1354:2011-07-06
1323:2012-04-04
1270:2011-07-05
1198:2011-01-15
1143:2011-07-04
1092:2011-07-04
1067:2011-07-06
1036:2011-08-02
1010:January 7,
988:2012-04-04
939:2011-07-14
901:2011-07-03
880:2012-04-04
851:2011-07-01
825:2011-07-01
806:References
692:SMR drives
654:Serial ATA
586:Interleave
486:Media rate
471:throughput
392:waste heat
236:rotational
143:voice coil
111:concentric
1735:. Seagate
602:IBM PC XT
447:off track
400:spun down
238:latency
106:seek time
100:Seek time
79:Seek time
18:Seek time
1961:cite web
1924:Archived
1906:26 April
1833:26 April
1807:Archived
779:See also
333:= 60/rpm
297:rotation
291:or just
2057:July 6,
2018:July 1,
1666:PCWorld
1641:ITWorld
1611:Seagate
1229:July 6,
388:spin-up
321:spin-up
293:latency
234:Average
212:Seagate
2053:. 2010
1864:
1294:
536:1x CDs
532:buffer
525:buffer
518:buffer
443:settle
275:15,000
267:10,000
231:speed
115:spiral
2051:(PDF)
1767:(PDF)
1760:(PDF)
1733:(PDF)
1419:. IBM
1348:(PDF)
1341:(PDF)
1219:(PDF)
1061:(PDF)
1054:(PDF)
1030:(PDF)
648:Some
410:Other
278:2.00
270:3.00
262:4.17
259:7,200
254:5.56
251:5,400
246:7.14
243:4,200
69:heads
2059:2011
2020:2011
1993:2022
1967:link
1953:2020
1908:2012
1862:ISBN
1835:2012
1369:drum
1292:ISBN
1231:2011
1170:2013
1119:2012
1012:2020
795:IOPS
785:vRPM
769:TRIM
465:The
433:The
414:The
193:DVRs
177:IOPS
159:and
55:The
35:and
715:.
596:10
477:or
422:or
205:AAM
189:dBA
113:or
59:or
2074::
1984:.
1963:}}
1959:{{
1943:.
1870:.
1860:.
1858:62
1784:.
1762:.
1664:.
1639:.
1609:.
1535:^
1247:.
1223:HP
1221:.
1207:^
1186:.
1161:.
966:^
956:.
910:^
860:^
834:^
598:MB
428:ÎĽs
150:ms
39:.
2061:.
2036:.
2022:.
1995:.
1969:)
1955:.
1910:.
1888:.
1837:.
1742:.
1717:.
1696:.
1674:.
1649:.
1624:.
1584:.
1558:.
1529:.
1503:.
1477:.
1451:.
1426:.
1405:.
1357:.
1326:.
1300:.
1273:.
1233:.
1201:.
1172:.
1146:.
1121:.
1095:.
1070:.
1039:.
1014:.
991:.
960:.
942:.
904:.
883:.
854:.
828:.
722:)
718:(
686:g
109:(
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
