There
are a few types of compact discs (CDs). Some are
meant to be used for playback only, while others can be used to record music or
data files. There are even some CDs that a person
can erase and reuse to record new data. The type of CD a person chooses often
depends on the machine in which he intends to use it, as some CDs aren’t compatible with certain types of machines.
CDs are
thin pieces of plastic that are coated with aluminum and used to store data for
use in a variety of devices, including computers and CD players. The main or
standard type of CD is called a CD-ROM; ROM means read-only memory. This type
of CD is used to store music or data that is added by a manufacturer prior to
sale. It can be played back or read by just about any CD player as well as most
computers that have CD drives. A consumer cannot use this type of CD to record
music or data files; it is not erasable or changeable.
If
consumers want to purchase recordable CDs to
record music store data files, they usually have some options available to
them. One is the CD-R, which is the typical choice for an individual who only
wants to add data files or music to a CD once. An individual uses a CD burner,
which is a component of many modern computer systems, to record to these discs.
Some
recordable CDs are classified as CD+R. This type
of disc allows consumers to record music or data to it, but provides nearly
twice the amount of space that is available with a CD-R. A CD-RW also has a
place among the recordable CDs. This one is a bit
different, however, because it allows consumers to erase it and record over it
again. Otherwise, it can be used in the same manner as CD-Rs and CD+Rs.
The type of machine an individual needs to play music or use data files depends on the type of CD he is using. An individual can usually play a CD-ROM on most CD audio players and computers as well as some digital video disc (DVD) players that are compatible with this disc type. CD-Rs and CD+Rs work on machines that are marked as digital audio recordable machines, in computer drives marked as compact disc recordable, and in CD and DVD players that are compatible with CD-Rs. When a consumer wants to use a CD-RW, however, he’ll need to use a player or CD drive that is specifically compatible with CD-RWs.
DVD-R -
pronounced ‘DVD R” (not “DVD dash R”) about DVD,s now a day’s
technology
DVD-R was created by the DVD Forum (see it at http://www.dvdforum.org/forum.shtml). The most common DVD-R is a writeonce 4.7gb “general purpose” disc, which is roughly equal to 120-minutes of standard playing lime.
Once recorded, a DVD-R can be played on most home DVD players. (Advertised as compatible with 90%+ of home DVD players.) General purpose DVD-R media is currently the cheapest & most common, and the newest DVD-R drives write at up to 4x. “General-purpose” discs are part of the industry’s copy-protection scheme, which employ CES scrambling to protect movies and music and game discs from being copied. These discs can be burned by “general-purpose” DVD writers such as the Pioneer DVR-A05/A04/103, Panasonic LF-D3 1 1/D321, Toshiba TSDR5002, Apple Superdrive, etc. Such drives cannot copy the playback descrambling codes on DVD movies or game discs, preventing easy duplication of commercial discs.
DVD-RW - pronounced ‘DVD R W” (not “DVD dash R W”)
DVD-RW was created by the DVD Forum (see it at http://www.dvdforum.org/forum.shtml). Generally comes in the single-sided, single layer 4.7gb capacity, which is roughly equal to 120-minutes of standard playing time.
In contrast to the write-once DVD-R types, the DVD-RW is fully re-writable or erasable up to 1,000 times. However, unlike the older DVD-RAM format, these particular erasables are NOT “random access”, meaning that you cannot erase bits and pieces of them. Instead, you have to completely erase the whole disc to reuse it The DVD-RW can be played on many home DVD players, but not as many as the DVD-Rs.
DVD+RW - pronounced ‘DVD plus R W”
This disc type was created by the “DVD+RW Alliance”. A few companies who back the DVD Forum (above) are also active in the DVD+RW Alliance, but the two standards are not compatible.
The first “plus type” DVD recording format is DVD+RW. It, like DVD-RW, is a rewriteable 4.7gb DVD disc. DVD+RW, does have a couple of technical advantages — (1) lossless linking (which enables some editing after recording without a full erasure that DVD-RW requires), (2) a special drag-and-drop file support on the desktop (otherwise known as DVD+MRW). Unfortunately, the DVD+RW disc type does not compare well with DVD-R as far as DVD playback compatibility. However, the actual level of DVD workability on players of DVD+RW is claimed to be about equal to DVD-RW.
DVD+R - pronounced ‘DVD plus R”
This disc type was created by the “DVD+RW Alliance”. A few companies who back the DVD Forum (above) are also active in the DVD+RW Alliance, but the two standards are not compatible.
The newest “plus type” format is DVD+R. It’s write-once disc is aimed at becoming more compatible with home DVD players. However, the fact is that so far it is only about as compatible as DVD-R discs are. Also, DVD+R discs are more expensive in today’s market, and are not burnable by 1st generation “plus-type” burners, which were designed only for the DVD+RW rewriteable discs. Like DVD-R “general purpose” media, DVD+R cannot copy the descrambling codes found on DVD video discs, so commercial discs cannot easily be duplicated. DVD+R drives have recently reached the same maximum recording speeds as DVD-R drives. (4x)
(once you write some data to +R disc, you can also add some more data later,again and again. but you can not erase the data once you writen.)
DVD-RAM
DVD-RAM is used for data backups and storage, and for editing of video or audio content prior to the production of a final distribution DVD. The DVD-RAM disc type is made to act a lot like a hard drive, where the disc can be formatted for Macintosh or Windows type computers. It can handle 100,000 or more erasures, and should last for many years. Of course it is not playable on most DVD players. Type 2.0 DVD-RAM discs can be removed from their cases to enable playback on the few players in which they are compatible. The newer DVD-RAM drives can handle any sized such disc, including 2.6, 5.2, 4.7 or 9.4gb discs.
Some drives support two or more of the above DVD formats. Most add support for CD-R / CD-R W burning as well. But, no currently-available drive has support for all of the D VD / CD formats.
DVD-R was created by the DVD Forum (see it at http://www.dvdforum.org/forum.shtml). The most common DVD-R is a writeonce 4.7gb “general purpose” disc, which is roughly equal to 120-minutes of standard playing lime.
Once recorded, a DVD-R can be played on most home DVD players. (Advertised as compatible with 90%+ of home DVD players.) General purpose DVD-R media is currently the cheapest & most common, and the newest DVD-R drives write at up to 4x. “General-purpose” discs are part of the industry’s copy-protection scheme, which employ CES scrambling to protect movies and music and game discs from being copied. These discs can be burned by “general-purpose” DVD writers such as the Pioneer DVR-A05/A04/103, Panasonic LF-D3 1 1/D321, Toshiba TSDR5002, Apple Superdrive, etc. Such drives cannot copy the playback descrambling codes on DVD movies or game discs, preventing easy duplication of commercial discs.
DVD-RW - pronounced ‘DVD R W” (not “DVD dash R W”)
DVD-RW was created by the DVD Forum (see it at http://www.dvdforum.org/forum.shtml). Generally comes in the single-sided, single layer 4.7gb capacity, which is roughly equal to 120-minutes of standard playing time.
In contrast to the write-once DVD-R types, the DVD-RW is fully re-writable or erasable up to 1,000 times. However, unlike the older DVD-RAM format, these particular erasables are NOT “random access”, meaning that you cannot erase bits and pieces of them. Instead, you have to completely erase the whole disc to reuse it The DVD-RW can be played on many home DVD players, but not as many as the DVD-Rs.
DVD+RW - pronounced ‘DVD plus R W”
This disc type was created by the “DVD+RW Alliance”. A few companies who back the DVD Forum (above) are also active in the DVD+RW Alliance, but the two standards are not compatible.
The first “plus type” DVD recording format is DVD+RW. It, like DVD-RW, is a rewriteable 4.7gb DVD disc. DVD+RW, does have a couple of technical advantages — (1) lossless linking (which enables some editing after recording without a full erasure that DVD-RW requires), (2) a special drag-and-drop file support on the desktop (otherwise known as DVD+MRW). Unfortunately, the DVD+RW disc type does not compare well with DVD-R as far as DVD playback compatibility. However, the actual level of DVD workability on players of DVD+RW is claimed to be about equal to DVD-RW.
DVD+R - pronounced ‘DVD plus R”
This disc type was created by the “DVD+RW Alliance”. A few companies who back the DVD Forum (above) are also active in the DVD+RW Alliance, but the two standards are not compatible.
The newest “plus type” format is DVD+R. It’s write-once disc is aimed at becoming more compatible with home DVD players. However, the fact is that so far it is only about as compatible as DVD-R discs are. Also, DVD+R discs are more expensive in today’s market, and are not burnable by 1st generation “plus-type” burners, which were designed only for the DVD+RW rewriteable discs. Like DVD-R “general purpose” media, DVD+R cannot copy the descrambling codes found on DVD video discs, so commercial discs cannot easily be duplicated. DVD+R drives have recently reached the same maximum recording speeds as DVD-R drives. (4x)
(once you write some data to +R disc, you can also add some more data later,again and again. but you can not erase the data once you writen.)
DVD-RAM
DVD-RAM is used for data backups and storage, and for editing of video or audio content prior to the production of a final distribution DVD. The DVD-RAM disc type is made to act a lot like a hard drive, where the disc can be formatted for Macintosh or Windows type computers. It can handle 100,000 or more erasures, and should last for many years. Of course it is not playable on most DVD players. Type 2.0 DVD-RAM discs can be removed from their cases to enable playback on the few players in which they are compatible. The newer DVD-RAM drives can handle any sized such disc, including 2.6, 5.2, 4.7 or 9.4gb discs.
Some drives support two or more of the above DVD formats. Most add support for CD-R / CD-R W burning as well. But, no currently-available drive has support for all of the D VD / CD formats.
A LECTURE ON BLU RAY DISC
CONTENTS :
CONTENTS Introduction
Characteristics of Blu-ray disc Specification of Blu-ray disc Comparision of
storage technologies Applications Conclusion
INTRODUCTION :
INTRODUCTION Blu-ray (BD) is a
next-generation optical disc format. The format was developed to enable
recording, rewriting and playback of high-definition video (HD), as well as
storing large amounts of data. The companies that have jointly established the
BD specifications are Hitachi, Ltd LG Electronics Matsushitha Electrical
Industrial Co. Ltd Mitsubishi Electric Corporarion
(Contd…) :
(Contd…) Pioneer Corporation Samsung
Electronics Co. Ltd Sony Thomson Royal Phillips Electronics Sharp Corporation
The name Blu-ray is derived from the blue-violet laser it uses to read and
write to the disc. The “e” was intentionally left out of the name due to
trademark restrictions
CHARACTERISTICS OF BLU-RAY :
CHARACTERISTICS OF BLU-RAY Life Span
Content Protection Cost Capacity Robustness of disc Compatible
Life Span :
Life Span In the case of ordinary discs,
the disc life is less . In the rewritable versions, as re-writing is done
repeatedly to one area of the disc most probably, the inner perimeter limiting
the disc life. BDFS (Blu-ray Disc File Structure is designed so as to avoid
this problem, by using a system that uses free disc spaces with equal frequency
Content Protection :
Content Protection Strongest content
and copy protection schemes ever developed Incorporation of Robust copy
mechanism Cost Long term Profitability model for content Providers Cheapest
Production cost
Capacity :
Capacity The Blu-ray disc enables
the recording, rewriting and playback of HD video up to 27 GB of data on a
single sided single layer. It is enough to put 2.5 hours of HDTV recording on
it. It also can record over 13 hours of standard TV broadcasting
Robustness of Disc :
Robustness of Disc Stronger
resistance to scratches and fingerprints The protective layer is hard enough to
prevent accidental abrasions and allows fingerprints to be removed by wiping
the disc with a tissue. Compatible The BD drives are designed to be backward
compatible, i.e. CDs and DVDs work equally well with the BD drives.
Principal BD Specifications :
Principal BD Specifications
Comparison of CD,DVD and B D
specification :
Comparison of CD,DVD and B D
specification Parameter CD DVD BD . Disk diameter 120 mm 120 mm 120 mm Disk
thickness 1.2 mm 1.2 mm 1.2 mm Laser wavelength 780 nm 650 nm 405 nm Numerical
aperture 0.45 0.60 0.85 Minimum pit length 0.83 um 0.4 um 0.138 um Data rate
1.2 Mb/sec 11 Mb/sec 36 Mb/sec Number of sides one ----- one or two Number of
data layers One ----- One or two Data capacity ~680 MB 4.7 GB (1L) 27 GB 8.5 GB
(2L) 1 7 GB (2L/2S)
Blu-ray disc and CD’s /DVD’s :
Blu-ray disc and CD’s /DVD’s 1 DVD =
5 to 10 CD’s 1 Blu-ray = 5 to 10 DVD’s !!!!!! Usage of a blue instead of a red
laser Improved lens specifications Backward compatibility (Comparison Between
Blu-ray n others)
Blu-ray Disc Applications :
Blu-ray Disc Applications High
definition television recording High definition video distribution High
definition camcorder archiving Mass data storage
Mass Data Storage :
Mass Data Storage The growing number
of broadband connections allowing consumers to download vast amounts of data
Conclusion : Conclusion Very soon BD’s will replace CDs and DVDs THANK
YOU…
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