The hard disk is a compact storage device that is used to store all the information supplied to the computer. Therefore, it is the place that serves to store all the data and programs, including the operating system.

A hard disk also serves to process information magnetically, from and to rotating disks through small heads.

The hard disk work process can be summarized as: input, processing, writing, reading and output. Its correct operation allows this process to be carried out without altering the information entered.

What is a hard drive and what is it for?

A hard drive is, in essence, the space where all the data on a computer is permanently stored. This unit is opposed to random or volatile memory, the data of which is permanently deleted as soon as the computer is restarted or turned off.

The storage capacity offered by a hard disk is essential for the operation of the computer. But let’s see what else a hard drive is for.

Permanent storage medium

The hard disk is used exclusively to store or save data that the user or computer may require at any time. All user programs, software, documents and multimedia files are saved on the hard drive.

Host the operating system

For a computer to function it must have an operating system hosted on the hard drive. Therefore, this storage unit is indispensable for installing and managing this software.

Program management

An operating system by itself, hardly meets the requirements of users, for this purpose programs designed to fulfill specific tasks are incorporated. Such is the case of programs such as Word, Excel, Power Point, among many others.

Store videos, texts, audios, games

The hard disk is not only used to store operating software, it can also house all kinds of personal files, which usually comprise a large size, such as videos, texts, audios, games, etc.

How does the hard drive work?

Hard drives are connected to the motherboard through a controller, the latter interpreting the processor’s commands and sending them to the hard drive.

Data on a conventional hard disk is held on circular coaxial plates covered with a thin layer of magnetic material for data recording and on which micro-heads for reading and writing are placed.

The trays are made of ceramic, metal or more generally glass. There are up to 8 plates inscribed with data read and / or write heads that move through an air cushion. The trays rotate very quickly with a minimum of 2,500 rpm in the counterclockwise direction.

All data is written in binary form of 1 and 0 in the read-write heads that are called “inductive”, these generate a positive or negative magnetic field in the trays. If the hard drive fails, data recovery specialists can potentially recover all the computer data written to the drive.

Hard disk types

There are several ways to classify hard drives by type. For example, they can be classified according to the way they store and deliver information. Another way to classify them is according to the type of connection with the device from which it is used, so the list is extensive. However, here we will talk a little in detail about the main hard drives, of the latest generation.

Hard disk HDD

The most commonly used HDD hard drives have a magnetized metal disk in the case. Data is stored and queried using a read / write head that floats over the disk without touching it.

SSD hard drive

SSD stands for “Solid State Drive” or “Solid State Disk” and is the most widespread alternative in addition to the HDD hard drive. Unlike the HDD, it does not have rotating discs or other moving parts. Also, SSD drives have an electronic storage medium, rather than the magnetic system.

For this reason, SSD drives are more robust than hard drives and less susceptible to mechanical failure. The most marketed models to install in low-mid-range and upper-mid-range laptops are the 500 GB and 1 TB, respectively.

Disco duro SSHD

SSHD (Solid State Hybrid) is the new hard disk technology that combines the advantages of HDD and SSD. Basically it is a HDD disk that incorporates a small SSD disk, for this reason they are called hybrid disks.

IDE or ATA hard drive

It is the oldest standard, which is even still used is ATA (IDE). These hard drives have a transfer speed of 133 MB / s and the connections are made using flat cables with 40-pin connectors. Multiple units can be connected in parallel.

SATA hard drive

The next standards were SATA 150MB / s, SATA II 300MB / s, and SATA III 600MB / s. These are all theoretical values ​​that in practice cannot be compared with actual operating values. These hard drives are available with storage capacities greater than 12 TB.

Characteristics of a hard drive

The transfer rate : it is the amount of data that can be read or written on the disk at any given time. It is expressed today in megabytes per second.

Latency : also called “rotation delay”. It is the time from when the disc found the track to where it finds the data.

The access time in milliseconds : This is the time that the storage unit sets to respond to a read or write request.

The cache: Keeps the data that the disk accesses most regularly to improve performance. Today, the minimum is 32, 64, even 128 MB of cache. The gain is quite small despite a tripled amount of cache.

Density and number of trays: the more capacity a disk has, the higher its density. The read heads will travel fewer areas to read more data. They can also be spread out on several trays.

Storage capacity: in the 80s we had hard drives of less than 100 MB, now we have units (SSD) up to 30.72 TB or what is the same 30,720 GB. A capacity really surprise you.

Rotational speed : disk drives rotate disks at several thousand revolutions per minute (rpm). The trays evolve at 7,200 rpm, or 5,400 rpm on laptops.

The connectivity standard : Sata 1 offers the speed of 192 MB / s. Sata 2 doubled this theoretical rate and the standard SATA 3 stream goes to 768MB / s in theory. For high-end hard drives, the current standard is SAS, which replaces SCSI.

For an external disk, the standard is USB. Currently, USB 3 and 3.1 are widely available. They offer a theoretical throughput of 600MB / s and 1.2GB / s.

Hermetic Enclosure : The hard drive is an extreme precision mechanic that is divided into enclosures in a completely hermetic manner. This prevents any particles entering the box from damaging the saved data. Hard drives are assembled in a clean room to maintain total purity within the enclosure.

Conclusion on hard drive usage

Finally, based on the needs and use that each user requires to give the hard disk, what a hard disk is for will be evaluated. An ordinary user, for example, does not need a hard disk with a capacity greater than 500 GB, but large organizations or simply those who store content in large formats, such as images, videos or music, need a greater storage capacity.

Samantha Robson
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Dr. Samantha Robson ( CRN: 0510146-5) is a nutritionist and website content reviewer related to her area of ​​expertise. With a postgraduate degree in Nutrition from The University of Arizona, she is a specialist in Sports Nutrition from Oxford University and is also a member of the International Society of Sports Nutrition.

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