A hard drive is composed of several coated round thin

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A hard drive is composed of several coated, round, thin plates of metal stacked on a spindle. Each plate is called a platter. When data is saved to a hard drive platter, a pattern of magnetized spots is created on the iron oxide coating of each platter. When the spots are aligned in one direction, they represent a 1; when they’re aligned in the other direction, they represent a 0. These 0s and 1s are bits (or binary digits) and are the smallest pieces of data that computers can understand. When data stored on the hard drive platter is retrieved (or read), your computer translatesthese patterns of magnetized spots into the data you have saved. The hard drive’s 66
access time, the time it takes a storage device to locate its stored data and make it available for processing, is faster than optical drives. Mechanical hard drive access times are measured in milliseconds (ms). For large-capacity drives, access times of approximately 12 to 13 milliseconds are typical. For comparison, a DVD drive can take over 150 milliseconds to access data.A solid state drive (SSD) uses electronic memory and has no mechanical motors or moving parts. Having no mechanical motors allows SSDs to offer incredibly fast access times, reaching data in only a tenth of a millisecond (0.1 ms). That’s about 100 times faster than mechanical hard drives. SSDs also have a great advantage when booting up because a mechanical hard drive has to wait for motors to bring the plates up to the final rotation speed. The start-up time of SSDs is so fast, in fact, that most desktop and laptop systems offer an option to use at least one SSD. This “system drive” may only be 20 GB large, but it holds the operating system and meansthe wake-up time for the system will be very fast. In addition, SSDs run with no noise, generate very little heat, and require very little power, making them a popular option in ultrabooks.Another new storage option is the solid state hybrid drive (SSHD). An SSHD drive is a combination of both a mechanical hard drive and an SSD into a single device SSHD drives offer a very small amount of SSD storage space, perhaps 8 GB. If it is enough to store the operating system however, it can have a huge impact on the system boot time.Optical drives are disc drives that use a laser to store and read data. Data is saved to a compact disc (CD), digital video disc (DVD), or Blu-ray disc (BD) (collectively calledoptical media) within established tracks and sectors, just like on a hard drive. But optical discs store data as tiny pits that are burned into the disc by a highspeed laser.These pits are extremely small, less than 1 micron (a millionth of a meter). Data is read from a disc by a laser beam, with the pits and nonpits (called lands) translating into the 1s and 0s of the binary code that computers understand. CDs and DVDs use a red laser to read and write data. Blu-ray discs get their name because they are readwith a blue laser light, which has a shorter wavelength and can focus more tightly

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