MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -Older hard disk drives used iron(III) oxide (Fe2O3) as the magnetic material, but current disks use a cobalt-based alloy.

Detailed explanation-2: -For hard drives, the magnetic alloys are typically CoPtCr (cobalt+platinum+chromium) with traces of boron or tantalum added at times to improve the stability of magnetic domains.

Detailed explanation-3: -Hard disks are flat circular plates made of aluminum or glass and coated with a magnetic material. Hard disks for personal computers can store terabytes (trillions of bytes) of information. Data are stored on their surfaces in concentric tracks.

Detailed explanation-4: -How is data stored on a hard disk? Data is stored on a hard drive in binary code, using 1s and 0s. The information is spread out on the magnetic layer of the disk(s) and are read or written by the read heads that ‘float’ above the surface thanks to the layer of air produced by the ultra fast rotation of the disk.

Detailed explanation-5: -The hard drive contains a spinning platter with a thin magnetic coating. A “head” moves over the platter, writing 0’s and 1’s as tiny areas of magnetic North or South on the platter. To read the data back, the head goes to the same spot, notices the North and South spots flying by, and so deduces the stored 0’s and 1’s.