Hard disk drive .. Everything you need to know about it
“A hard disk drive (HDD), hard disk, or hard disk is an electromechanical data storage device that stores and retrieves digital data using magnetic storage and one or more magnetically encapsulated rapidly rotating hard disks. The dishes are paired with magnetic heads, usually arranged on a movable actuator arm, which reads and writes data on the surfaces of the dish. The data is accessed by random access method, which means that individual blocks of data can be stored and retrieved in any order.
Hard drives are a type of non-volatile storage, holding the stored data even when they are turned off. Modern hard drives are usually in the form of a small rectangular box.”
Definition of hard drives
“Introduced by IBM in 1956, hard drives were the dominant secondary storage medium for general-purpose computers beginning in the early 1960s. Hard drives have maintained this position in the modern era of servers and personal computers, although personal computing devices mass-produced hard drives, such as mobile phones and tablets, rely on flash memory storage devices.”
Historically more than 224 companies have produced hard drives, although after extensive industry standardization, most units are manufactured by Seagate, Toshiba and Western Digital Hard drives dominate the productive storage volume (exabytes per year) for servers Although production is growing slowly (by exabytes shipped, sales revenue and unit shipments are declining because SSDs enjoy transfer rates Higher data, higher storage density, better reliability, and much lower latency and access times.”
Hard disk drive .. Everything you need to know about it
SSDs, most of which use NAND flash memory, have a slightly higher yield than hard disk drives. Flash storage products more than doubled hard disk drive revenues as of 2017. Although hard disk drives cost four to nine times as expensive as a bit, they are replacing hard disk drives in applications where speed and power consumption, small size, capacity High and durability are important. The bit cost of SSDs does not decrease, nor does the price premium of HDDs.
The primary characteristics of a hard disk drive are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of 1000: a 1 terabyte drive with a capacity of 1000 GB (gigabyte; where 1 GB = 1 billion (109) bytes). Usually some hard drive capacity is not available to the user because it is used by the file system and computer operating system, and there is likely to be internal redundancy for patching and recovery.
There is also confusion regarding storage capacity, as capacities are specified in decimal gigabytes (powers of 1000) by hard disk manufacturers, while the most commonly used operating systems refer to 1024 capacity, resulting in fewer advertisements. Performance is determined by the time required to move the heads to a track or cylinder (average latency) adding the time it takes the required sector to move under the head (average latency, a function of physical rotational speed in revolutions per minute), and finally the speed at which The data is transmitted (data rate).
Hard disk drive .. Everything you need to know about it
The most common form factors for modern hard drives are 3.5″ for desktop computers and 2.5″ for mainly laptops. Hard disk drives connect to systems via standard interface cables such as PATA (Parallel ATA), SATA (Serial ATA), USB, or SAS (Serial Attached SCSI) cables.
