When a Read/write Head Makes Contact With the Hard Disk's Surface, It Causes a Head:
Hard drive
Updated: 08/02/2020 by Computer Hope
A hd (sometimes abbreviated equally a hard bulldoze, Hard disk, or HDD) is a non-volatile data storage device. It is usually installed internally in a figurer, attached directly to the disk controller of the calculator'due south motherboard. It contains one or more platters, housed inside of an air-sealed casing. Data is written to the platters using a magnetic head, which moves rapidly over them as they spin.
Internal hard disks reside in a drive bay, connected to the motherboard using an ATA, SCSI, or SATA cablevision. They are powered by a connectedness to the computer'due south PSU (ability supply unit).
Examples of data stored on a figurer'southward hard drive include the operating organisation, installed software, and the user's personal files.
Why does a computer need a hard bulldoze?
A computer requires an operating system to permit users to interact with and use it. The operating system interprets keyboard and mouse movements and allows for the employ of software, like an Cyberspace browser, word processor, and video games. To install a computer operating organization, a hard drive (or another storage device) is required. The storage device provides the storage medium where the operating arrangement is installed and stored.
A difficult drive is besides required for the installation of whatever programs or other files you want to go on on your reckoner. When downloading files to your reckoner, they are permanently stored on your difficult bulldoze or another storage medium until they are moved or uninstalled.
Can a reckoner work without a hard drive?
Without a difficult drive, a computer tin can plow on and POST. Depending on how the BIOS is configured, other bootable devices in the kicking sequence are also checked for the necessary boot files. For example, if the USB device is listed in your BIOS boot sequence, y'all tin boot from a bootable USB flash bulldoze in a computer without a hard drive.
Examples of bootable flash drives include a Microsoft Windows installation deejay, GParted Alive, Ubuntu Live, or UBCD. Some computers also back up booting over a network with a PXE (preboot execution environment).
Hard drives in mod computers
Modern computers oft employ an SSD (solid-country drive) every bit the primary storage device, instead of an HDD. HDDs are slower than SSDs when reading and writing data, but offering greater storage capacity for the price.
Although an HDD may still be used as a computer'south primary storage, information technology's mutual for it to exist installed as a secondary deejay drive. For example, the chief SSD may incorporate the operating system and installed software, and a secondary HDD may be used to shop documents, downloads, and sound or video files.
Tip
New computer users may misfile RAM (retention) with their disk bulldoze. Unlike an HDD or SSD, RAM is a "volatile" data storage device, pregnant it can store data only when the estimator is powered on. See our retentivity definition for a comparing between memory and disk storage.
Hard drive components
As shown in the picture higher up, the desktop hard bulldoze consists of the following components: the caput actuator, read/write actuator arm, read/write head, spindle, and platter. On the dorsum of a hard drive is a excursion board chosen the deejay controller or interface board. This circuit is what allows the hard drive to communicate with the computer.
How is a hard drive connected to a computer?
An internal hard drive connects to the estimator using ii means: a data cable (IDE, SATA, or SCSI) to the motherboard and a power cable to the power supply.
Where is the hard drive institute in a computer?
All primary computer hard drives are found inside a computer case and are attached to the calculator motherboard using an ATA, SCSI, or SATA cable. Hard drives are powered by a connection to the PSU (power supply unit of measurement).
Notation
Some portable and desktop computers may accept newer wink drives that connect directly to the PCIe interface or some other interface and not use a cable.
What is stored on a difficult bulldoze?
A difficult drive can store any data, including pictures, music, videos, text documents, and any files created or downloaded. Also, hard drives store files for the operating system and software programs that run on the reckoner.
What are the sizes of hard drives?
The difficult drive is ofttimes capable of storing more data than any other drive, simply its size can vary depending on the blazon of drive and its age. Older hard drives had a storage size of several hundred MB (megabytes) to several GB (gigabytes). Newer hard drives have a storage size of several hundred gigabytes to several TB (terabytes). Each year, new and improved technology allows for increasing difficult drive storage sizes.
Note
If y'all are trying to notice the physical dimensions of a hard drive, their physical sizes are either 3.5" for desktop computers or 2.5" for laptops. SSDs range from i.eight" to five.25".
How is data read and stored on a hard bulldoze?
Data sent to and read from the hard drive is interpreted by the disk controller. This device tells the hard drive what to do and how to motion its components. When the operating system needs to read or write information, it examines the hard drive's Fatty (File Allocation Tabular array) to determine file location and available write areas. Once that is determined, the disk controller instructs the actuator to move the read/write arm and align the read/write head. Because files are often scattered throughout the platter, the caput needs to motility to unlike locations to access all information.
All information saved and stored on a traditional hard drive, like the above example, is done magnetically. Subsequently completing the above steps, if the computer needs to read information from the difficult bulldoze, information technology would read the magnetic polarities on the platter. One side of the magnetic polarity is 0, and the other is 1. Reading this every bit binary data, the computer tin can empathise what the data is on the platter. For the reckoner to write data to the platter, the read/write head aligns the magnetic polarities, writing 0'due south and 1's that can be read later.
External and internal hard drives
Although most hard drives are internal, at that place are also stand-alone devices called external difficult drives or portable hard drives that backup information on computers and expand the available space. External drives are often stored in an enclosure that helps protect the drive and allows it to interface with the computer, usually over USB, eSATA, or FireWire. An excellent instance of an external backup device that supports multiple hard drives is the Drobo.
External hard drives come in many shapes and sizes. Some are big, virtually the size of a volume, while others are about the size of a large smartphone. External hard drives can be very useful since they usually offer more space than a jump drive and are withal portable. The film is an example of a laptop hd drive enclosure from Adaptec. With this enclosure, the user installs a laptop hard drive of whatsoever storage capacity into the enclosure and connect it via USB port to the estimator.
HDD being replaced past SSD
SSDs (solid-country drives) have started to replace HDDs (hard disk drive drives) considering of the distinct functioning advantages they have over HDD, including faster admission times and lower latency. While SSDs are becoming pop, HDDs continue to exist used in many desktop computers largely due to the value per dollar that HDDs offer over SSDs. However, more and more laptops are start to utilize SSD over HDD, helping to ameliorate the reliability and stability of laptops.
History of the difficult bulldoze
The first hard drive was introduced to the market by IBM on September 13, 1956. The hard drive was commencement used in the RAMAC 305 arrangement, with a storage capacity of 5 MB and a cost of near $50,000 ($10,000 per megabyte). The difficult drive was built-in to the calculator and was not removable.
In 1963, IBM developed the start removable difficult drive, having a 2.6 MB storage capacity.
The first hard drive to have a storage capacity of one gigabyte was likewise developed by IBM in 1980. Information technology weighed 550-pounds and price $twoscore,000.
1983 marked the introduction of the commencement 3.5-inch size hard drive, developed past Rodime. It had a storage capacity of 10 MB.
Seagate was the first company to introduce a 7200 RPM hard drive in 1992. Seagate also introduced the first 10,000 RPM difficult bulldoze in 1996 and the outset xv,000 RPM hard bulldoze in 2000.
Should I say "hd drive" or "difficult drive"?
Both "hd" and "hard bulldoze" are correct and hateful the aforementioned thing. However, we recommend using the term "difficult drive" in your writing or when describing a hard drive. The term "hard drive" helps to distinguish it from an SSD (solid-country bulldoze), which contains no platters, disk-shaped components, or moving parts.
Computer acronyms, Difficult drive terms, Hardware terms, Hybrid hard drive, Storage device, VHD
Source: https://www.computerhope.com/jargon/h/harddriv.htm