Hard-Disk

A HARD DISK DRIVE (HDD), HARD DISK, HARD DRIVE OR FIXED DISK IS A DATA STORAGE DEVICE USED FOR STORING AND RETRIEVING DIGITAL INFORMATION USING ONE OR MORE RIGID RAPIDLY ROTATING DISKS (PLATTERS) COATED WITH MAGNETIC MATERIAL.

HARD-DISK, Background: First hard disk was introduced by IBM in 1956, and It was the size of

dishwasher with fifty platters, each with two feet diameter. And those platters could hold only 160KB of data.

HDDs became the dominant secondary storage device for general-purpose computers by the early 1960s. Continuously improved, HDDs have maintained this position into the modern era of servers and personal computers.

Seagate technology announced the first Winchester 5.25” hard disk drive with four platters capacity of 5MB in 1980.

The platters are paired with magnetic heads arranged on a moving actuator arm, which read and write data to the platter surfaces.

 Data is accessed in a  random - access manner, meaning that individual blocks of data can be stored or retrieved in any order and not only sequentially. 

The primary characteristics of an Hard Disk Drive are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of 1024: a 1-terabyte (TB) drive has a capacity of 1,024 gigabytes (GB; where 1 gigabyte = 1 billion bytes)

The two most common form factors for modern HDDs are 3.5-inch, for desktop computers, and 2.5-inch, primarily for laptops.

HDDs are a type of non-volatile memory, retaining stored data even when powered off.

Advantages of Hard-Disk

Hard disk store data long terms. Data are safely store in hard disk . Hard disk can store large amount of data in terms of Mb, Gb, Tb. Hard disk is easier to buy in most stores. Hard disk is the backup memory because these memories are used to

store data for future application. Now a days , operating system and other software, business data and

important information are stored in Hard disk. Data is not lost when you switch off the computer. Hard disks can be replaced and upgraded as necessary.

Disadvantages of Hard disk

Hard disk consumes more powers. Hard disks eventually fail which stops the computer from

working. Data errors are frequent. It is large in size than other storage device. It can be broken if dropped.

Reference:

Fundamental of computer science Fundamental of information technology. Wiki Hard disk: https://en.wikipedia.org/wiki/Hard_disk_drive

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