Blue-ray Discs


The need to archive large amounts of data is a common requirement for organizations and individuals alike as access to data becomes simple and speedy. While organizations have a distinct need for large capacity storage for backup of server as well as client data, such storage requirements are not always justified for casual users. With the increase in broadband penetration as well as significant changes in the entertainment industry, high storage space requirements are slowly going to become mainstream. Optical storage consisted only of CD media in a not so distant past and the use of DVD media is getting common with the decrease in prices of DVD writers and media. This month we were part of another breakthrough in optical storage technology with Sony’s launch of Blu-ray enabled devices in India—an optical storage writer and a notebook featuring Blu-ray technology.

What is Blu-ray?

Blu-ray is the next-generation technology in optical storage after VHS, CD and DVD. The Blu-ray standard was jointly developed by a group of consumer electronics and PC companies called the Blu-ray Disc Association (BDA), spearheaded by Sony. It is designed for high-density storage of highdefinition video and data. It is currently competing with the HD DVD format for wide adoption as the preferred next generation optical standard.

How Blu-ray works

A Blu-ray drive looks and works in traditionally the same way as any other optical drive. The difference is that Blu-ray drives use a violet-blue laser to read data from an optical drive media rather then the infrared light that is used by CDs and red laser light used by DVD writers. The violet-blue color falls into the higher frequency segment in the visible spectrum of light, thus resulting in a lower wavelength (refer to box). The wavelength of the laser used in Blu-ray drives is 405 nm. To put it into perspective, a CD drive uses an infrared laser operating at a wavelength of 780 nm while a DVD drive uses a red laser operating at a wavelength of 650 nm. So, as we can see, using a light source that has a lower wavelength causes a smaller laser beam. This is advantageous because it can focus better at a point on the media surface from a fixed distance as the wave travels faster and hits the surface before it disperses. Thus the light ray used in a Blu-ray drive is more accurate in pinpointing a particular area on the media surface. As the focusing capability gets finer, media manufacturers can increase the track pitch (refer to box) on the media thus increasing the media’s storage capacity.

Advantages of Blu-ray

Size: The Blu-ray drive comes in a five-and-a quarter inch form factor which is the same as other optical storage devices like CD or DVD. This means that your Blu-ray drive will look and feel the same as any other optical drive. It will seamlessly integrate itself into the drive bay of PC cabinet or even a laptop. A Blu-ray media supports the 12 cm form factor and also has a thickness of 1.2 mm, the same as a CD or DVD media.

Storage capacity:
Even though the Blu-ray disc supports the same form factor as a CD or a DVD disc, it supports a whopping capacity of 25 GB on a single layer disk. This means that you can store up to 5 DVDs or 32 CDs worth of data on a single Blu-ray disc.

Copy protection and digital rights management:
The movies that are distributed on a DVD media use an encryption system called CSS (Content Scrambling System). This encryption system has been defeated thus allowing users to decode (rip) the contents of a DVD movie. This has been taken a step further in Blu-ray which uses AACS (Advanced Access Content System) which makes use of stronger encryption algorithms like AES (Advanced Encryption Standard). The AACS standard provisions each individual player with a unique set of decryption keys which are used in a broadcast encryption scheme. This approach allows licensors to “revoke” the decryption keys associated with the player. Thus, if a given player’s keys are compromised by an attacker, the licensing authority can simply revoke those keys in future content, making the keys/player useless for decrypting new titles. So you cannot rip the BD content like a DVD content unless the encryption scheme is compromised. Blu-ray discs will also have the capability to add information at a physical level (called ROM-Mark in case of Blu-ray) which makes it difficult to make carbon copies of the media. This helps reduce piracy.

Performance:

With the use of a violet-blue light, the track densities can be increased and more data can be stored in the same form factor of an optical disc. Blu-ray drives perform the read/write operations using Constant Linear Velocity allowing them to sustain a constant throughput rate. This would not result in any artifacts or distortions while watching a Blu-ray movie, for example.

Disadvantages of Blu-ray:

Costs of drive and media: Just like it happens with any new technology, the initial costs are always high. The Blu-ray drive includes two lasers instead of the single laser system used in CD and DVD drives. This is done in order to facilitate backward compatibility with the existing CD and DVD optical media. This increases the production cost due to the use of additional hardware. The production of Blu-ray disc will involve more cost, because the companies will have to add equipment for the cover layer. Also, because the Blu-ray media use a completely different design, their production is not on the lines of a CD or DVD media.

Disc and data reliability: The cover layer of the Blu-ray disc is very thin measuring 0.1 mm compared to the 0.6 mm coating of a CD or DVD media. This makes the Blu-ray discs more prone to damage from scratches and smudges. To overcome this limitation, an extra layer of protective material needs to be added to the Blu-ray disc, which in turn increases the cost of the media.

Last word: Blu-ray drives are the next step in optical storage. Now that the Blu-ray drives are a reality, we will be able to see 1080p high-definition movies on our computer systems. Also, with HD cameras becoming more mainstream, a two-hour movie can be recorded on the Blu-ray medium. This can be used in Blu-ray players and you can view high definition movies on your plasma or LCD TV. We would also like to add that Blu-ray media is not as easily available as a CD or a DVD disc. Also, the cost of the media is Rs 1,000; instead one can buy six DVDs at a total price of Rs 120 to store equal amounts of data. In future when prices of the drives and media plummet and the media becomes mainstream, Blu-ray might be a good storage alternative. Sony VAIO VGN-AR18GP Notebook The Sony VAIO VGN-AR18GP desktop replacement notebook is the first to use the next generation Blu-ray optical drive.

Features: Powered by the dual core Intel Centrino Duo T2600 processor (Yonah) running at 2.16 GHz, it has enough horsepower to play your high-definition movie content. It features 1 GB of DDR2 memory which is pretty much standard for all entertainment desktops. Another striking feature of this laptop is the Nvidia Gforce Go 7600GT graphics card that comes with 256 MB of memory making it a complete gaming system. The 1920x1200 high resolution facilitates playing 1080p HD video. With three USB 2 ports, a mini FireWire and an ExpressCard/54 slot catering for modern peripherals. A media card reader supporting memory stick and SD formats are in the front, and a 0.37- megapixel webcam is hidden in the top bezel of the screen. The HDCP-compliant HDMI output is welcome, and there’s also S-Video in/out and a VGA output. Connectivity options include a 10/100 Ethernet, a 56K modem, Bluetooth and an 802.11a/b/g wireless LAN. We were not so impressed with the audio capability of the speakers built into this notebook. It lacked in quality sound effects like bass, treble; considering it is an entertainment notebook, Sony could have done better. Build quality The first thing that catches your eye when you look at the notebook is its massive size. The size is justified considering its massive 17-inch TFT wide screen. Picture quality on the LCD is crisp and crystal clear. The notebook is black, complemented with a glossy finish. Although this provides for good looks, it is prone to smudges. It weighs a good 3.8 kg, so you will have a good exercise carrying it around. The expansion slots are neatly covered with a series of flaps coated with a metallic finish.

Performance: We were quite impressed with the performance of the VAIO. In our performance tests, the Sisoft Sandra CPU arithmetic benchmark score was at par with that of most high-end notebooks (it recorded scores of 14,732 Dhrystones and 10,864 Whetstones). The heavy duty processor underperformed in the battery mode, which made watching HD movies a impossible task. The filesystem benchmark crossed the 50 MB/s mark—a result of two 5400 rpm drives configured in RAID 0, which was pretty impressive. A record score of 5126 3D Marks ensured top spot in graphics. It meant that we could play Doom 3 at decent framerates, at 1600x1200 resolution with 4x antialiasing enabled. It provided about an hour and 10 minutes of battery life—way too low for watching HD movies.

Verdict: The Sony VAIO VGN-AR18GP retails for Rs 1,99,900. Like most other Sony notebooks, it is priced very high. However, it is future proof and you are left in awe the moment you see a HD movie on it. Sony BWU-100A Blu-ray writer Features The BWU-100A drive supports recording both 50 GB and 25 GB BD-R (write once) and BD-RE (rewritable) discs, as well as 4.7 GB DVD+R/+RW/RAM, 8.5GB DVD+R Dual Layer, and CD-R/-RW discs. Sony bundles the Cyberlink suite along with the drive that can be used to view HD quality movies and a Blu-ray mastering software to write to the Blu-ray writable and rewritable disks. Performance The drive was able to copy 23.3 GB data on a single sided Blu-ray disk in about 47 minutes at 2x speeds. This means that the drive can write at a speed of about 8.44 MBps which is equivalent to that of a 12x DVD writer but slower than recent writers that can write to DVD media at speeds of about 12 MBps. Verdict At a whopping price of Rs 44,300, we feel this writer is not meant for the average user. It instead aimed at studio editors who need lots of storage space for editing HD movies.

Jargon

Wavelength: We all know that light is a form of electromagnetic waves. Like any other wave, light travels in the form of a sine wave. The distance (measured in the direction of propagation) between two points in the same phase in consecutive cycles of a wave is called wavelength.

Track Pitch: The data track of an optical disc is a spiral starting from the center of the disc; The distance (in micro meters) between the two intersection points on the concentric rows starting from the center of the circle is known as track pitch. When the track pitch is reduced, it means that the distance between the concentric rows is lower and that the resulting track is much longer, thus you can store more data.

Blue-ray Discs Blue-ray Discs Reviewed by Unknown on 4:45 AM Rating: 5

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