Современные информационные
технологии/1.компьютерная инженерия.
Student, Rustam Nosirov
Assistant, Olga Oleshitskaya
Kryvyi Rih Technical University
APPLICATION OF BLU-RAY TECHNOLOGY
Evolution of computer technologies occurs
faster than in any other fields of science.
Period of time, when computer capacity doubles, reduces twice. 1 GHz
processors were developed in 22 years, but 2 GHz ones were developed only in
one year and a half. Winchester drives of 160-180 gigabytes are ordinary thing
for today. Recently RAID-massifs from hundreds of hard-drives were created with
this purpose. Miniaturization, increasing operation speed and recording density
are questions we deal with every day. Volumes, speed and frequencies are
doubled and quadrupled and nobody wonders at this. But there is a field where
there was no development until recently. This is field of pluggable data
carrier.
In 1960 Theodor Maiman, who worked at research
laboratory of Hews company (California), created the first working laser. As
the rule, new devices are developed for specific tasks solution, specific
functions implementation. It is interesting to know that from the very
beginning laser was put into operation into many fields of human life.
Unusual properties allowed laser penetration into
science and industry, medicine and nuclear technologies, space and our everyday
life. Doubtless lasers are used in computer technologies as well. Recording and
reading data from CD or DVD are possible with the help of lasers.
In near 2002 world companies such as Hitachi,
LG, Matsushita (Panasonic), Thomson, Philips, Samsung, Sharp, SONY and Pioneer
have intended creation of a new format different from DVD. There was also a
split at this stage: one party has suggested finishing red laser (DVD), and
another undertook working out absolutely new blue – violet technology.
Subsequently format of modified red laser will named HD-DVD, and blue-
violet-blue-ray.
Blu-ray Association will be created a little
later. Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer,
Philips, Samsung, Sharp, Sony, TDK and Thomson. Moreover
are members of this association. Seven of the eight biggest film studios agreed
to produce movies using Blu-ray technology. They are Disney, Fox, Warner,
Paramount, Sony, Lionsgate and MGM, Universal Studio. HD DVD joined Studio Channel, Ocean Films, Wild Side, DreamWorks.
Both formats compatible are Warner and FPE (Fox, Pathe, Gaumot).
One of the formats developed now is Blu-ray
Disc (BD). It was created for carriers of great volumes of data and video of
high resolution. This technology is developed by the group of companies united
in to Blu-ray Disc Association (BDA). The leading developer of this technology
is company Sony. The competitor of technology Blu-ray is technology HD DVD
which main developer Toshiba is.
Blu-ray has occurred from the base technology
in which blue-violet laser is used for data recording and reading. Blu-ray is
combination of English words “Blue” (blue-violet laser) and “Ray” (an optical
beam). «Dark blue» laser has considerably smaller wave length, than red laser
of DVD-system that also allows writing down data of larger density. Therefore
on Blu-ray disks of 12 sm diameter it is possible to store more information,
than on such one-way single-layer disks. The volume of single-layer disk
Blu-ray approximately corresponds to the volume of 35 compact discs. Laser
generates dispersing beam of light - that means that cross-section size of the beam increases with distance. Simple
demonstration of this phenomenon is wall illumination by small lamp beam — the
more distance to the wall is the more light is. To reduce stain size a beam is
focused. Thus it appears that the less lens focal length is, the smaller stain
is to focus light ray. It is also used in BD technology- the focusing cone has
larger corner - optics of larger aperture (0,85 in comparison with 0,6 in DVD
devices) is used. To be exact, this is system of two high-quality lenses. As
distance from the lens to focusing point is less, protective layer from the
working side is also necessary to be thinner. Nowadays technology Blu-ray is
accessible only in Japan for recording HDTV (TV of high resolution).
First Blu-ray disks were placed into plastic
cards. Data was placed too close to the surface there. It
makes these disks too sensitive to external actions and scratches. This
disadvantage raised doubts that disks with cartridges would not compete with
ordinary CD and DVD disks Moreover, CD and DVD disks are attractive because of
their low price as well, but they could cause additional expenses on
cartridges.
In 2004 development of new polymer covering solved this problem. This covering protected disks from dust and
scratches. It was worked out by TDK and named "Durabis". It allows Blu-ray emptying from dust with the help of
paper napkins which damage disks of CD and DVD formats. As disks of CD and DVD
formats are produced on the basis of old optic carriers, they have the same
demerits. But Blu-ray with "Durabis"
covering can work even after scratching by screwdriver.
BD + is technology which allows changing protection codes dynamically.
This is one of the methods of coding data on BD for content against copying. It
means that constant change of protection code will do impossible breaking of
all BD disks after breaking protection of one of them as it was with DVD. DVD
content was protected using technology CSS. But program DeCSS released in 1999
allows removing protection from any DVD disks.
BD technology also supports digital water
marks. Digital water marks is a record way of copyrighting latent labels to the
carrier. They should prevent content copying without permission. Protection
technology AACS of association LA should also be used.
Finally, protection (High-bandwidth Digital Content Protection) HDCP
will be also used in BD technology. This is licence technology which allows
reproducing content with the maximum resolution only on licence players. The
players which do not have any HDCP key will not be able to reproduce content
with maximum resolution or will not reproduce it at all.
Nowadays technology Blu-ray provides basic
speed of data transmission in 36 Mbit/seconds. Devices prototypes which can
transfer data with 2x speed are developed. In future it is planned to reach 8x
speed. The numerical aperture 0,85,
used in this technology, allows receiving higher speeds of record and
reading. It also means that BD record mode needs smaller capacity of laser beam
and smaller speed of disc rotation to receive the same speed of data
transmission as DVD and HD DVD have.
Technology Blu-ray has some advantage. They are
larger volume of carriers, more sophisticated optical system of laser head, as
well as innovative polymeric sheeting. This technology is compatible to earlier
technologies and provides sufficient level of content protection.
Summing up, advantages of Blu-ray Discs are not
only in their enormous capacity, but compatibility with various drives.
Disadvantages of Blu-ray are high price for drives and disks and problems of
backward compatibility with previous data carriers. Price problem will be
settled in the nearest future after development of copying protection system.
Compatibility of Blu-ray depends on several factors. They are mass of putting
into operation, advertisement and future popularity. If there is Blu-ray in
every computer, old formats will be removed and there will be no necessity to
support their compatibility. Mass of putting into operation depends on price of
drives and disks and flexibility of license policy of the leading computer
companies.
Literature
1.
"What is Blu-ray Disc and HD
DVD?". http://www.videohelp.com/hd.
Retrieved on 2008-02-16
2. "Blu-ray profiles, everything
you wanted to know". 2007-12-17. http://www.gizmorepublic.com/media/blu-ray-profiles-everything-you-wanted-know-1270.
Retrieved on 2007-12-19