What is Hard Disk Definition Functions and Types 2024 Updated

What is Hard DiskWhat is Hard Disk

What is Hard Disk

In this article, you will know what is Hard Disk and what are the types of it? Hard disks are also often called Disk drive or “Hard Disk Drive (HDD)”. Just as a library is required to handle books in the library, the same computer also needs such a place in which it can store digital data.

Computers use two types of storage devices to store and process digital content (Document, Image, Videos, Software, Operating system, Program). In which Hard Disk is a secondary memory device. It keeps the data stored permanently.

Whereas the primary memory device (RAM) serves to process the computer’s programs. It is also called temporary memory. Hard Disk is seen as an important component of a computer because no computer will work without it. In this post we will tell you what is a hard disk in a computer? In which you will get to know a lot about Hard Disk. So let’s first know, what is called a hard disk and then we will talk about other aspects of it.

Hard Disk Definition, functions and types

What is Hard Disk

Hard Disk, also called Hard Disk Drive (HDD), is a non-volatile memory hardware device. Hard disk work is to permanently store and retrieve computer data. They are called non-volatile device, which can store any type of data in the computer for a long time. That is, the computer keeps the data safe even after power off. Hard Disk is also called Secondary Storage Device. It exists inside a computer case (CPU) and is connected to the computer motherboard using data cables (PATA, SCSI, SATA).

Hard Disk uses magnetic storage to store and retrieve digital information. That is why it is also called Electro-mechanical data storage device. The hard disk consists of one or more circular rotating disks to store the data. Each platter has a very thin strip, which is made using magnetic material. There are many tracks and sectors present in these platters and it rotates through the spindle. When the platter starts rotating, a Read / Write arm in the Hard Disk moves it from right to left.

What are the different types of Hard Disk?

  1. PATA (Parallel Advanced Technology Attachment) – This is the oldest type of hard disk. It was first used in 1986. PATA Hard Disk uses the ATA interface standard to connect to the computer. It was earlier referred to as Integrated Drive Electronics (IDE). It is a medium speed hard disk, its data transfer rate is up to 133MB / s. This drive stores data using magnetism.
  2. SATA (Serial Advanced Technology Attachment) – In most of today’s computers and laptops you will find this type of Hard Disk. The data transfer rate of SATA Hard Disk is higher than a PATA drive. Its speed can be from 150MB / s to 600MB / s. SATA cables are very thin and flexible, which is much better than PATA cables. It is better than the old hard disk drive in many ways.
  3. SCSI (Small Computer System Interface) – This type of hard disk uses a small computer system interface to connect to the computer. This is quite parallel to the IDE hard drive. The new version of the SCSI Hard Disk (16-bit ultra – 640) has a data transfer speed of up to 640 MBps and can connect to 16 devices with a cable of 12 meters in length.
  4. SSD (Solid State Drives) – It is one of the latest drives today. Much better and faster than all other hard disk devices. SSD uses flash memory technology to store data. Its data access speed is very fast. It costs a lot more than an HDD drive.

Hard disk parts

Some of the major components of Hard Disk and their functions are shown below.

  1. MAGNETIC PLATTERS is an important part of it, in which digital information is stored magnetically. In this, the data is saved in binary form (0 to 1).
  2. READ / WRITE HEAD is a small magnet mounted next to the read right arm. It moves the platter from right to left and works to record and store information.
  3. The read-write arm rotates with the help of ACTUATOR.
  4. READ-WRITE ARM is the back of the read right head, both of them are connected.
  5. SPINDLE is a type of moter, it is present in the middle of the platter. With its help, the platters move around.
  6. CIRCUIT controls the effect of data from the BOARD platter.
  7. CONNECTOR transmits data from the circuit board to the read-write and platter.
  8. LOGIC BOARD is a type of chip that controls all information input or output from HDD.
  9. HSA is the parking area of ​​the reed right arm.

Apart from this, there are many more parts of Hard Disk. If you want complete information about them, click here.

Function of Hard Disk

The main function of a Hard Disk is to store computer data forever. Therefore it is also called Permanent Storage. This data can be of many types, such as your personal files, documents, software, operating system etc. How much data can be stored in these hard disks, it depends on the storage capacity of the Hard Disk. Today you will find such hard disks whose capacity to store data ranges from gigabytes to terabytes.

What is SSD?

The full form of SSD is Solid State Drive. You can also call it a replacement for HDD (Hard Disk Drive). In this, flash memory is used to store data. SSD is stronger than an electromechanical drive. Therefore it is also called solid-state device. The access time of this type of drive is very long. It does not sound like the rest of the hard disk and runs without interruption.

It is much smaller in size than a hard disk drive, so it occupies less space inside the CPU. SSD has two major components that make it. Which includes flash controller and NAND flash memory chips. SSDs are used in most computers and laptops today. It is a better storage device than HDD.

Major differences between HHD and SSD (SSD vs HDD)

Let’s talk about HDD first. It is made of magnetized element and has mechanical parts inside it. Its storage capacity is very high, due to which you can store 1TB or more data in your computer. If you buy an HDD, you will get it at very cheap prices. The data access speed of HHD is quite sluggish. That is, it takes a long time to start your program and computer.

SSD is much faster than this and this is also a big achievement. It uses Integrated circuits (IC, Chips) to store data. It is much smaller in size than a HDD. It comes with different storage capacity. But its price is very high which is difficult for the common man to bear. But if you buy an SSD with less storage, then your computer becomes very fast.


In this post you have learned what is Hard Disk and how it is there? Hopefully, by now you must have known about the hard disk. If you use a computer, then we would advise you to never open the hard disk that is in it, otherwise it can be damaged. We have explained in detail about almost all aspects of the hard disk in this post, but still if you have any question, please tell in the comment below. If you want, you can share this post to your friends. Thank you.

Also Check: What is Hardware in Computer 

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