[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:07.25,0:00:10.82,Default,,0000,0000,0000,,Imagine an airplane flying\None millimeter above the ground
Dialogue: 0,0:00:10.82,0:00:14.03,Default,,0000,0000,0000,,and circling the Earth\Nonce every 25 seconds
Dialogue: 0,0:00:14.03,0:00:17.34,Default,,0000,0000,0000,,while counting every blade of grass.
Dialogue: 0,0:00:17.34,0:00:20.55,Default,,0000,0000,0000,,Shrink all that down so that it fits\Nin the palm of your hand,
Dialogue: 0,0:00:20.55,0:00:24.30,Default,,0000,0000,0000,,and you'd have something equivalent\Nto a modern hard drive,
Dialogue: 0,0:00:24.30,0:00:28.46,Default,,0000,0000,0000,,an object that can likely hold\Nmore information than your local library.
Dialogue: 0,0:00:28.46,0:00:32.91,Default,,0000,0000,0000,,So how does it store so much information\Nin such a small space?
Dialogue: 0,0:00:32.91,0:00:37.12,Default,,0000,0000,0000,,At the heart of every hard drive\Nis a stack of high-speed spinning discs
Dialogue: 0,0:00:37.12,0:00:40.52,Default,,0000,0000,0000,,with a recording head \Nflying over each surface.
Dialogue: 0,0:00:40.52,0:00:46.28,Default,,0000,0000,0000,,Each disc is coated with a film\Nof microscopic magnetised metal grains,
Dialogue: 0,0:00:46.28,0:00:49.59,Default,,0000,0000,0000,,and your data doesn't live there\Nin a form you can recognize.
Dialogue: 0,0:00:49.59,0:00:52.77,Default,,0000,0000,0000,,Instead, it is recorded \Nas a magnetic pattern
Dialogue: 0,0:00:52.77,0:00:55.82,Default,,0000,0000,0000,,formed by groups of those tiny grains.
Dialogue: 0,0:00:55.82,0:00:58.17,Default,,0000,0000,0000,,In each group, also known as a bit,
Dialogue: 0,0:00:58.17,0:01:01.12,Default,,0000,0000,0000,,all of the grains have \Ntheir magnetization's aligned
Dialogue: 0,0:01:01.12,0:01:03.60,Default,,0000,0000,0000,,in one of two possible states,
Dialogue: 0,0:01:03.60,0:01:06.80,Default,,0000,0000,0000,,which correspond to zeroes and ones.
Dialogue: 0,0:01:06.80,0:01:08.67,Default,,0000,0000,0000,,Data is written onto the disc
Dialogue: 0,0:01:08.67,0:01:12.58,Default,,0000,0000,0000,,by converting strings of bits \Ninto electrical current
Dialogue: 0,0:01:12.58,0:01:14.99,Default,,0000,0000,0000,,fed through an electromagnet.
Dialogue: 0,0:01:14.99,0:01:18.61,Default,,0000,0000,0000,,This magnet generates a field\Nstrong enough to change the direction
Dialogue: 0,0:01:18.61,0:01:21.14,Default,,0000,0000,0000,,of the metal grain's magnetization.
Dialogue: 0,0:01:21.14,0:01:24.10,Default,,0000,0000,0000,,Once this information is written \Nonto the disc,
Dialogue: 0,0:01:24.10,0:01:28.84,Default,,0000,0000,0000,,the drive uses a magnetic reader\Nto turn it back into a useful form,
Dialogue: 0,0:01:28.84,0:01:33.47,Default,,0000,0000,0000,,much like a phonograph needle\Ntranslates a record's grooves into music.
Dialogue: 0,0:01:33.47,0:01:37.63,Default,,0000,0000,0000,,But how can you get so much information\Nout of just zeroes and ones?
Dialogue: 0,0:01:37.63,0:01:40.30,Default,,0000,0000,0000,,Well, by putting lots of them together.
Dialogue: 0,0:01:40.30,0:01:45.25,Default,,0000,0000,0000,,For example, a letter is represented\Nin one byte, or eight bits,
Dialogue: 0,0:01:45.25,0:01:47.88,Default,,0000,0000,0000,,and your average photo \Ntakes up several megabytes,
Dialogue: 0,0:01:47.88,0:01:50.86,Default,,0000,0000,0000,,each of which is 8 million bits.
Dialogue: 0,0:01:50.86,0:01:54.78,Default,,0000,0000,0000,,Because each bit must be written onto\Na physical area of the disc,
Dialogue: 0,0:01:54.78,0:01:58.83,Default,,0000,0000,0000,,we're always seeking to increase\Nthe disc's areal density,
Dialogue: 0,0:01:58.83,0:02:03.57,Default,,0000,0000,0000,,or how many bits can be squeezed\Ninto one square inch.
Dialogue: 0,0:02:03.57,0:02:08.91,Default,,0000,0000,0000,,The areal density of a modern hard drive\Nis about 600 gigabits per square inch,
Dialogue: 0,0:02:08.91,0:02:15.52,Default,,0000,0000,0000,,300 million times greater than that\Nof IBM's first hard drive from 1957.
Dialogue: 0,0:02:15.52,0:02:17.93,Default,,0000,0000,0000,,This amazing advance in storage compacity
Dialogue: 0,0:02:17.93,0:02:20.73,Default,,0000,0000,0000,,wasn't just a matter \Nof making everything smaller,
Dialogue: 0,0:02:20.73,0:02:22.91,Default,,0000,0000,0000,,but involved multiple innovations.
Dialogue: 0,0:02:22.91,0:02:26.15,Default,,0000,0000,0000,,A technique called the thin film\Nlithography process
Dialogue: 0,0:02:26.15,0:02:29.85,Default,,0000,0000,0000,,allowed engineers \Nto shrink the reader and writer.
Dialogue: 0,0:02:29.85,0:02:32.77,Default,,0000,0000,0000,,And despite its size, \Nthe reader became more sensitive
Dialogue: 0,0:02:32.77,0:02:39.09,Default,,0000,0000,0000,,by taking advantage of new discoveries in\Nmagnetic and quantum properties of matter.
Dialogue: 0,0:02:39.09,0:02:43.38,Default,,0000,0000,0000,,Bits could also be packed closer together\Nthanks to mathematical algorithms
Dialogue: 0,0:02:43.38,0:02:46.60,Default,,0000,0000,0000,,that filter out noise\Nfrom magnetic interference,
Dialogue: 0,0:02:46.60,0:02:51.47,Default,,0000,0000,0000,,and find the most likely bit sequences\Nfrom each chunk of read-back signal.
Dialogue: 0,0:02:51.47,0:02:54.46,Default,,0000,0000,0000,,And thermal expansion control of the head,
Dialogue: 0,0:02:54.46,0:02:57.55,Default,,0000,0000,0000,,enabled by placing a heater \Nunder the magnetic writer,
Dialogue: 0,0:02:57.55,0:03:02.68,Default,,0000,0000,0000,,allowed it to fly less than\Nfive nanometers above the disc's surface,
Dialogue: 0,0:03:02.68,0:03:06.66,Default,,0000,0000,0000,,about the width of two strands of DNA.
Dialogue: 0,0:03:06.66,0:03:08.42,Default,,0000,0000,0000,,For the past several decades,
Dialogue: 0,0:03:08.42,0:03:12.56,Default,,0000,0000,0000,,the exponential growth in computer\Nstorage compacity and processing power
Dialogue: 0,0:03:12.56,0:03:15.82,Default,,0000,0000,0000,,has followed a pattern \Nknown as Moore's Law,
Dialogue: 0,0:03:15.82,0:03:23.10,Default,,0000,0000,0000,,which, in 1975, predicted that information\Ndensity would double every two years.
Dialogue: 0,0:03:23.10,0:03:25.99,Default,,0000,0000,0000,,But at around 100 gigabits \Nper square inch,
Dialogue: 0,0:03:25.99,0:03:30.18,Default,,0000,0000,0000,,shrinking the magnetic grain's further\Nor cramming them closer together
Dialogue: 0,0:03:30.18,0:03:34.36,Default,,0000,0000,0000,,posed a new risk\Ncalled the superparamagnetic effect.
Dialogue: 0,0:03:34.36,0:03:37.54,Default,,0000,0000,0000,,When a magnetic grain volume is too small,
Dialogue: 0,0:03:37.54,0:03:41.48,Default,,0000,0000,0000,,its magnetization is easily disturbed\Nby heat energy
Dialogue: 0,0:03:41.48,0:03:44.43,Default,,0000,0000,0000,,and can cause bits \Nto switch unintentionally,
Dialogue: 0,0:03:44.43,0:03:46.71,Default,,0000,0000,0000,,leading to data loss.
Dialogue: 0,0:03:46.71,0:03:50.82,Default,,0000,0000,0000,,Scientists resolved this limitation\Nin a remarkably simple way:
Dialogue: 0,0:03:50.82,0:03:55.90,Default,,0000,0000,0000,,by changing the direction of recording\Nfrom longitudinal to perpendicular,
Dialogue: 0,0:03:55.90,0:04:01.22,Default,,0000,0000,0000,,allowing areal density to approach\None terabit per square inch.
Dialogue: 0,0:04:01.22,0:04:04.86,Default,,0000,0000,0000,,Recently, the potential limit has been\Nincreased yet again
Dialogue: 0,0:04:04.86,0:04:07.68,Default,,0000,0000,0000,,through heat assisted magnetic recording.
Dialogue: 0,0:04:07.68,0:04:11.45,Default,,0000,0000,0000,,This uses an even more thermally\Nstable recording medium,
Dialogue: 0,0:04:11.45,0:04:14.89,Default,,0000,0000,0000,,whose magnetic resistance \Nis momentarily reduced
Dialogue: 0,0:04:14.89,0:04:18.52,Default,,0000,0000,0000,,by heating up a particular spot \Nwith a laser
Dialogue: 0,0:04:18.52,0:04:20.54,Default,,0000,0000,0000,,and allowing data to be written.
Dialogue: 0,0:04:20.54,0:04:23.56,Default,,0000,0000,0000,,And while those drives are currently\Nin the prototype stage,
Dialogue: 0,0:04:23.56,0:04:28.30,Default,,0000,0000,0000,,scientists already have the next potential\Ntrick up their sleeves:
Dialogue: 0,0:04:28.30,0:04:30.29,Default,,0000,0000,0000,,bit-patterned media,
Dialogue: 0,0:04:30.29,0:04:35.27,Default,,0000,0000,0000,,where bit locations are arranged \Nin separate, nano-sized structures,
Dialogue: 0,0:04:35.27,0:04:40.30,Default,,0000,0000,0000,,potentially allowing for areal densities\Nof twenty terabits per square inch
Dialogue: 0,0:04:40.30,0:04:41.78,Default,,0000,0000,0000,,or more.
Dialogue: 0,0:04:41.78,0:04:46.25,Default,,0000,0000,0000,,So it's thanks to the combined efforts\Nof generations of engineers,
Dialogue: 0,0:04:46.25,0:04:48.01,Default,,0000,0000,0000,,material scientists,
Dialogue: 0,0:04:48.01,0:04:49.98,Default,,0000,0000,0000,,and quantum physicists
Dialogue: 0,0:04:49.98,0:04:53.02,Default,,0000,0000,0000,,that this tool of incredible power\Nand precision
Dialogue: 0,0:04:53.02,0:04:55.81,Default,,0000,0000,0000,,can spin in the palm of your hand.