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HDD is the most common type of hard drive on computers. So what is this hard drive, what features does it have, how many types, let’s find out the drive with lassho.edu.vn!
What is HDD?
HDD, also known as hard drive (Hard Disk Drive, abbreviated: HDD) is a device used to store data on the surface of circular disks covered with magnetic material. Hard drives are “non-volatile” memory, which means they don’t lose data when power is stopped on them.
Laptop HDDs currently have two common speeds of 5400 RPM (revolutions per minute) or 7200 RPM , with the exception of a few hard disks that spin up to 15,000 RPM.
Structure of HDD
Disk Cluster
The disc assembly consists of a rotating shaft that is responsible for transmitting the motion of the magnetic disk and the motor is mounted coaxially with the rotating shaft and the discs.
Reader cluster
The reader cluster includes:
– Head: The head reads/writes data.
– Need to move the reader (head arm or actuator arm).
Circuit assembly
- Control circuit : Responsible for controlling the coaxial motor, controlling the movement of the read head moving lever to ensure it reaches the correct position on the disc surface.
- Data processing circuit : Used to process the read / write data of the hard drive.
- Buffer memory (cache or buffer) : Is a place to temporarily store data during data reading/writing. The data on the cache will be lost when the hard drive stops being powered.
- The power connector supplies power to the hard drive.
- Connector to communicate with the computer.
- The jumpers set the hard drive’s working mode : Select the hard drive’s working mode (SATA 150 or SATA 300) or the order of the channels on the IDE interface (master or slave). or self-selected), select other working parameters, etc.
Hard disk cover
The hard drive case consists of the following parts: The base contains the components mounted on it, the cover covers to protect the internal components.
The hard drive enclosure has the main function of locating components and ensuring a tight seal that does not allow dust to get inside the hard drive. In addition, the hard disk cover is also impact resistant (to a low level).
Magnetic disc
A magnetic disk is a circular metal disk mounted inside a hard drive. Some disks are mounted on a spindle motor to create multiple data storage surfaces in a smaller space.
To maintain organized data storage and retrieval, magnetic disks are arranged into specific structures. These specific structures include tracks (tracks), sectors, and clusters.
- Track : Each magnetic disk is divided into thousands of tightly packed concentric circles, called tracks. All information stored on the hard drive is recorded on the track.
- Sector : Each track is broken down into smaller units called sectors. Sector is the basic unit of data storage on the hard drive.
- Cluster : Sectors are often grouped together to form clusters.
Working principle of HDD
The basic working principle is to have a circular disc made of aluminum (or glass, or ceramic) coated with a magnetic material. In the middle of the drive there is a rotating motor to read/write data, combined with these devices are electronic boards to control the read/write head to the correct position of the disc from earlier while spinning to decode information.
So your operations such as copying music, movies or data from your computer to another device (USB, Hard Drive) fast or slow also depend on this part, moreover the material of the components in the hard drive. The better this is, the more secure the data you save on this will be.
Types of HDDs
HDD hard drive includes HDD Internal and HDD External, in which:
- HDD Internal: 3.5-inch in size and most have a capacity of 4 TB. HDD Internal has a read and write speed of about 530 MB/s. Usually, this hard drive costs nearly 2-7 million. But in general, the Internal HDD is still more affordable than the External HDD.
- External HDD : 2.5-inch in size, most with a maximum capacity of 2 TB powered via USB or Thunderbolt connectivity. However, the mobile hard drive market is increasingly diverse, with many specially designed models with huge storage capacity such as Backup Plus Desktop with capacities up to 5 TB.
Specifications on HDD
- Disk Capacity HDD- HDD capacity : Hard drive capacity is calculated in units: bytes, Kb, MB, GB, TB.
- Average Seek Time HDD – Average seek time HDD : Is the average seek time it takes the reader to move from one Cylinder to another random Cylinder.
- Random Access Time HDD – HDD random access time : The average time it takes the hard drive to search for a random data. This is an important parameter that affects the performance of the hard drive and the system.
- Data access time HDD – Data access time HDD : Total seek time = Average Seek time (time to move the head from one cylinder to another) + Random Access Time (one sector search time) on a specified track).
- MTBF HDD – Mean Time Between Failures HDD : The reliable working time of HDD is the life of the hard drive (in hours). With hard drives operating at 15,000 rpm with MTBF up to 1.4 million hours.
Features of HDD
About the popular maximum capacity
In terms of capacity, HDD has reached about 1TB or more.
About speed
An HDD will take time to ramp up to operating specifications, and will continue to be slower than an SSD during normal use.
About fragmentation
HDDs work best with larger files laid out in contiguous blocks. That way the player can start and end reading it in one continuous motion. When the hard drive begins to write, large files can become scattered around the platter, leading to fragmentation.
About durability
HDDs can experience physical damage that causes the storage device to stop working or cause data loss. Additionally, HDDs are electromechanical devices – with moving parts – that often make them vulnerable to physical shock.
About popularity
Because of the low cost, HDD hard drives are often more abundant than SSDs. We often see cheap laptops often equipped with this type of hard drive. In addition, mid-range and high-end laptops that use SSDs also have a place to add an HDD.
Advantages and disadvantages of HDD
Advantage:
– HDD hard drive is designed with a simple design .
– Capable of storing a lot of data but the price is extremely reasonable.
– HDD size is usually 3.5” and 2.5” respectively for desktop and laptop computers.
Defect:
– Uses more power than SSD.
– Loud noise when operating.
– Affected by magnetism .
Popular HDD brands
Popular HDD brands today include: Western Digital (WD), Seagate, Toshiba, Hitachi, Dell, Kiwivision, Sony,…
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