Which of the following uses a shorter wavelength and allows for almost six times more data storage
than on a DVD?
A.
Blu-ray Disc
B.
Digital Linear Tape (DLT)
C.
Bluetooth
D.
Blue Jacking
Explanation:
Blu-ray Disc, also known as Blu-ray or BD, is an optical disc storage medium. It is designed to
supersede the standard DVD format for storing high-definition video, PlayStation 3 games, and other
data, with up to 25 GB per single layered, and 50 GB per dual layered disc. Blu-ray Disc was
developed by the Blu-ray Disc Association, a group representing makers of consumer electronics,
computer hardware, and motion
pictures. The disc has the same physical dimensions as standard DVDs and CDs. It is called Blu-ray
Disc because of the blue-violet laser which is used to read the disc. Blu-ray uses a shorter
wavelength, a 405 nm blue-violet laser, and allows for almost six times more data storage than on a
DVD.
Answer option C is incorrect. Bluetooth is a standard for very low powered and short-range radio
connections. It is used to link personal access devices (PDA), mobile phones and laptops, and
provides them with Internet access via hot spots. Bluetooth uses the 2.4 Ghz spectrum with a data
rate of about 1 Mbps. As a radio technology, Bluetooth does not require line of sight like an infrared
connection requires. The maximum transmission range of Bluetooth is around 10 meters. Highpowered Bluetooth would extend the range to 100 meters.
Answer option D is incorrect. Blue Jacking is the process of sending unsolicited messages over
Bluetooth to Bluetooth-enabled devices such as mobile phones, PDAs or laptop computers, sending
a vCard which typically contains a message in the name field to another Bluetooth enabled device
via the OBEX protocol.
Answer option B is incorrect. Digital Linear Tape (DLT) is a magnetic tape data storage technology
developed by Digital Equipment Corporation (DEC). DLT drives support hardware data compression.
Media are guaranteed for 30 years of data retention under specified environmental
conditions. However, they are easily damaged by mishandling. Current manuurers of cartridges for
the DLT market are Fujifilm, Hitachi/Maxell and Imation.
Reference:
“http://en.wikipedia.org/wiki/Blu-ray_Disc”