Editing Hard disk drive (section)

=== Data transfer rate ===
{{As of|2010}}, a typical 7,200-rpm desktop HDD has a sustained "disk-to-[[disk buffer|buffer]]" data transfer rate up to {{nowrap|1,030 Mbit/s}}.<ref name="AutoMK-71" /> This rate depends on the track location; the rate is higher for data on the outer tracks (where there are more data sectors per rotation) and lower toward the inner tracks (where there are fewer data sectors per rotation); and is generally somewhat higher for 10,000-rpm drives. A current, widely used standard for the "buffer-to-computer" interface is {{nowrap|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{{As of?|date=September 2023}} disk-to-buffer transfer rates. 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. Transfer rate can be influenced by [[file system fragmentation]] and the layout of the files.<ref name="itworld-2001-04-18" />

HDD data transfer rate depends upon the rotational speed of the platters and the data recording density. Because heat and vibration limit rotational speed, advancing density becomes the main method to improve sequential transfer rates. Higher speeds require a more powerful spindle motor, which creates more heat. While areal density advances by increasing both the number of tracks across the disk and the number of sectors per track,<ref>{{cite web |title=GLOSSARY of DRIVE and COMPUTER TERMS |url=http://ftp.seagate.com/techsuppt/misc/glossary.txt |publisher=Seagate |access-date=August 4, 2018}}</ref> only the latter increases the data transfer rate for a given rpm. Since data transfer rate performance tracks only one of the two components of areal density, its performance improves at a lower rate.<ref>{{cite journal |title=Bit Patterned Magnetic Recording: Theory, Media Fabrication, and Recording Performance |journal = IEEE Transactions on Magnetics|volume = 51|issue = 5|pages = 1–42|publisher=HGST, a Western Digital Company |arxiv = 1503.06664|doi = 10.1109/TMAG.2015.2397880|year = 2015|last1 = Albrecht|first1 = Thomas R.|last2 = Arora|first2 = Hitesh|last3 = Ayanoor-Vitikkate|first3 = Vipin|last4 = Beaujour|first4 = Jean-Marc|last5 = Bedau|first5 = Daniel|last6 = Berman|first6 = David|last7 = Bogdanov|first7 = Alexei L.|last8 = Chapuis|first8 = Yves-Andre|last9 = Cushen|first9 = Julia|last10 = Dobisz|first10 = Elizabeth E.|last11 = Doerk|first11 = Gregory|last12 = He Gao|last13 = Grobis|first13 = Michael|last14 = Gurney|first14 = Bruce|last15 = Hanson|first15 = Weldon|last16 = Hellwig|first16 = Olav|last17 = Hirano|first17 = Toshiki|last18 = Jubert|first18 = Pierre-Olivier|last19 = Kercher|first19 = Dan|last20 = Lille|first20 = Jeffrey|last21 = Zuwei Liu|last22 = Mate|first22 = C. Mathew|last23 = Obukhov|first23 = Yuri|last24 = Patel|first24 = Kanaiyalal C.|last25 = Rubin|first25 = Kurt|last26 = Ruiz|first26 = Ricardo|last27 = Schabes|first27 = Manfred|last28 = Lei Wan|last29 = Weller|first29 = Dieter|last30 = Tsai-Wei Wu|display-authors = 29|bibcode = 2015ITM....5197880A|s2cid = 33974771}}</ref>