The 4k blu ray specifications allows for three

Info icon This preview shows pages 10–11. Sign up to view the full content.

The 4K Blu-ray specifications allows for three capacities sizes, each with their own data rate. The disk capacities are 50 gigabytes with 82 megabits per second, 66 gigabytes with 108 megabits per second,and 100 gigabytes with 128 megabits per second. Just like CD and DVD drives, Blu-ray drives are rated according to the drive's speed. A 1X Blu-ray drive reads information at 4.5 megabytes per second. Remember that we are dealing with a capital "B" here, indicating bytes instead of bits. For true high definition video, we need to have a 2X Blu-ray drive which transfers information at nine megabytes per second. The current, practical maximum speed for Blu-ray discs is about 12X. Higher speeds of rotation cause too much wobble for the disc to be written to properly. How Blu-ray Drives Works 2:20-3:36 A Blu-ray drive functions very much the same as a CD drive and a DVD drive. However, there is one very important difference: the color of the laser used to read information from the disc. CD and DVD drives use a red laser. You can think of the red laser looking something like this. That's your laser beam. However, a Blu-ray uses a blue laser. The key difference is that red laser, as you can see here, has a relatively long wavelength, and the blue laser has a very tight wavelength. When we say wavelength, we're talking about the distance from peak to peak and the wave form of the light beam itself. Because the Blu-ray drive uses a blue laser, which has a much shorter wavelength as compared to the red laser used with CDs and DVDs, we can pack more information on the same disc. This works well if the disc in here is a Blu-ray disc. We'll draw this with blue to depict a Blu-ray disc.But what happens if you put a DVD in a Blu-ray drive? We'd have a problem if we only had this blue laser because the blue laser would not be able to read the information on the bottom of the CD or DVD. Most Blu-ray drives have a second read head that uses a red laser. So if we have our traditional DVD or CD, we can use the red laser with the longer wavelength to read information from the bottom of the traditional CD or DVD disc using the Blu-ray drive. Summary 3:37-3:43 Now, let's review what we discussed in this video. We've talked about what Blu-ray is, how it works, and which formats are available. DVD (Digital Video Disc or Digital Versatile Disc) is an optical media standard that can be used to store large amounts of different types of data (computer data, video, audio). Optical Media Characteristics Compact Disc (CD) CDs were first developed to store digital music. Later, the CD technology was adapted to store digital computer data. A CD: Can hold 74 to 80 minutes of audio Is 120 millimeters in diameter Is 1.2 millimeters thick CD-ROM stands for compact disc read-only memory. CD-ROMs are identical in appearance to audio CDs, and data is stored and retrieved in a very similar manner. CD-ROMs: Have lands and pits and use reflective light to interpret the data on the disc Hold about 737 MB of data with error correction or 847 MB total
Image of page 10

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 11
This is the end of the preview. Sign up to access the rest of the document.
  • Spring '14
  • Serial ATA

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern