Today is the age of digitisation but at the same time to keep data is equally important. As you know to keep your important text, images, video, digital document in the form of data matter for you. Its very important when your hard disk of Desk Top of lap top get full with storage then it becomes essential to purchase external hard disk. 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 connected to systems by standard interface cables such as PATA (Parallel ATA), SATA (Serial ATA), USBor SAS (Serial attached SCSI) cables.
A hard disk drive (HDD), hard disk, hard drive or fixed disk[b] 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. 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. HDDs are a type of non-volatile memory, retaining stored data even when powered off.
The primary characteristics of an HDD are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of 500 gb, 1000: a 1-terabyte (TB) drive has a capacity of 1,000 gigabytes (GB; where 1 gigabyte = 1 billion bytes) & 2 TB. Their prices may vary from company to company. All these hard disks are easily available online also with good discount offer.