Hard disk, Components, Characteristics, Performance and Hard disk controllers

By: Prof. Fazal Rehman Shamil
Last modified on January 16th, 2021

The hard disk is a type of magnetic disk. It is also called a fixed disk because it is fixed in the system unit. A hard disk consists of several circular disks called platters sealed inside a container. The container contains a motor to rotate the disk. It also contains an access arm and a read and write head to read and write data to the disk. The platters are used to store the data. A platter in a hard disk is coated with magnetic material.

hard disk parts
Figure: Hard disk 

The hard disk used in computers spin at the speed of 5400 to 15000 revolutions per minute. The speed at which the disk spins is a major factor in its overall performance. The high rotational speed allows more data to be recorded on the disk surface.

Characteristics of Hard Disk

    Some important characteristics of the hard disk are as follows:

  • The hard disk provides a large storage capacity. The capacity of a personal computer hard disk is from 160 GB to 2TB and more.
  • It is much faster than the floppy disk.
  • It is the primary media for storing data and programs.
  • It is more reliable than a floppy disk.
  • Data stored on the hard disk is safer than the floppy disk.

 Hard disk performance

       The following factors affect the performance of the hard disk:

Seek time:  it is also called positioning performance. It is the time required by reading and writes head to the correct location on the disk.it is often used with rotational speed to compare the performance of hard drives. It is measured in milliseconds.

Spindle speed: it is also called transfer performance. It is the speed at which the driver transfers the data.

Latency: it is the time required by the spinning platter to bring the desired data to read and write head.

External and Removable Hard Disks

      An external hard disk is a separate hard disk that is connected to the USB port on the CPU. Some hard disks can also communicate with the system unit wirelessly.

A remove able hard disk is a type of hard disk that can be connected to the system unit using the USB port or firewire port.

There are some advantages to removable hard disks as follows:

  1. These can be used to transfer a large number of files from one place to another place.
  2. These can be used to back up important files.
  3. These can be used to store a large number of audio, and video.

Miniature hard disks

      These disks are very small hard disks. These disks are available in a different size. The devices such as portable and smartphones have miniature hard disks. These

It provides more storage capacity than flash memory.       

Hard disk controllers

It consists of chips and electronic circuits. It also controls the transfer of data, instructions, and information between system and system unit.

           There are 4 types of hard disk interfaces for personal computer which are as follows:

1: SATA        

                  SATA stands for serially advanced technology attachment. It used for serial signals to transfers data, instruction and information. The main advantage of SATA is that cables are thinner, longer and higher. The external hard disks can use the SATA interface that is much faster than USB.


             EIDE stands for Enhanced Integrated Drive Electronics. EIDE is a device interface that used signals parallelly to transfer the instructions and data etc. The approximate data transfer speed of EIDE is up to 133 Mbps.


             SCSI stands for Small Computer System Interface. It is used as a parallel signal and cannot support from 8 to 15 devices. SCSI can support hard disks, disk drives, printers, etc.

4: Disk cache

                      It is used to improve hard disk performance.it is a type of ram program instructions and data that the user is working with. When the CPU needs the information it first looks at the cache from the hard disk and if it doesn’t need the information it retrieves information from the hard disk.

Difference between SATA and HDD

What is SATA?

SATA stands for Serial Advanced Technology Attachment. SATA is used for transferring data from hard disk drives to computer systems. SATA is a point of interface for communication with other storage devices like disk drives, optical drives, SSD etc. The cables of SATA are thinner and flexible.SATA has many advantages over the hard drive.

Advantage of SATA

  • SATA Cables are flexible and thinner
  • The transfer rate of SATA is very high than HHD.
  • It is very easy to manage cables length.
  • SATA manages RAID in an efficient way.
  • It provides an internal-external interface.
  • It is equipped with NCQ (Native Command Queuing)

SATA does not have jumper cables and due to this no fussing with Master/slave/cable select setting

Disadvantages of SATA

  • Sate drives can be used only in an IDE.
  • The computer can only use a cheap SATA to IDE reversible interface.
  • if the cable length is too long, serial devices driven at high speed can be subject to interference

What is HDD?

In all PCs, the traditional hard disk used as a storage device. A typical hard drive contains a circular disc called a platter used to store data. The disc rotates, allowing the read-write arm to read data on the disc and write data to tithe working of platter affect the performance of hard disk like The faster the platter spins, the faster the hard drive works, which can depend on how quickly your operating system responds, and how long it takes applications installed on the drive to load and open. The Older hard drives use an IDE port to connect to the motherboard of a PC, but now many modern hard drives use a SATA connection. The new version of SATA, SATA III, is found on modern motherboards, and able to the fastest possible data transfers for an HDD.

Advantages of HDD

  • It has a large capacity for storing data
  • It is much faster than optical disks like DVD’S
  • It has Persistent storage
  • HDD easily replaced and upgraded.

Disadvantages of HDD

  • It depends upon on moving parts
  • The disk surface can be damaged easily.
  • It consumes heavy power.
  • It makes more noise.
  • Its read/write speed is slower than RAM.

Comparison of HDD versus SSD

Stands for Solid State Drive Hard Disk Drive
Heat, Electricity and Noise Less rotation required.

Uses less power.

Less heat or noise.

More heat generation.

More noise.

More electricity to rotate the platters.


Speed SSD has lower latency

SSD has faster read/writes

SSD has supported more input-output operations per second.


HDD  supports fewer input-output operations per second.

HDD has higher latency

HDD has longer read/write times


Components SSD architecture has NO moving parts. HDD architecture has moving parts.
Defragmentation Performance doesn’t care about fragmentation.

Defragmentation is not compulsory as in HDD.

The performance is not better and the main reason is disk fragmentation. We need frequent defragmentation.
Weight Less in weight. Heavy in weight.

Checking the health of Hard disk with HD TUNE

HD Tune is a software used to monitor the performance of the Hard Disk. This software has many features. This software can check the performance of the hard disk, provide information about the partition of the hard disk, provide the health check report of the HD. It also scans your whole disk and tells you if there is any sort of errors in your hard disk. This software is so useful if you wanna know about the temperature. I have discussed the core features of the HD tune application, now I will try to explain these features one by one will help the readers to understand how we can use this software and from where we can find what, etc.


Before going into the detailed stage, let me tell you about some quick things we can perform through the icons available.

Checking the health of Hard disk with HD TUNE
Checking the health of Hard disk with HD TUNE
  1. Copy information:

By pressing the icon I have mention number 1, you can copy all the information of any feature of your choice. For example, in the above pic If have press the number 1 icon, it will copy the details of BENCHMARK details to the clipboard and you can paste it anywhere. But first, we need to start the software by pressing the start icon then it will copy the details. We can copy the information on the rest of the features also.

  1. Screenshot:

Number 2 icon is of the screenshot we can quickly take the screenshot of the application screen by pressing this icon, after that we can paste it in the word file or anywhere else where we can use the picture.

  1. Save Screenshot:

This icon is also for taking a quick screenshot of the application screen but this icon will not copy the picture to the clipboard rather it will ask the location from you where you want to save the picture. We can save pictures of different times, we can compare those pictures for analyzing our hard disk.

  1. Option:

The icon mention at number 4 is the options icon, we can change the setting of this software, we have furthermore options available in these option settings. Please find below the picture which pops up after pressing the options icon.

Checking the information of Hard disk with HD TUNE
Checking the information of Hard disk with HD TUNE

These were some short quick icons details we can use for our use. Now let’s move to the detailed analysis of this software.

  • Benchmark:
    After pressing the start icon, the HD tune software will start analyzing the hard disk and will show the results in graph mode as well as in the digital mode view. The transfer rate will be shown in MB per second rate. On the right side of the picture, we can see that my hard disk minimum speed is 0.7 megabytes per second, the maximum speed is 105.5 Megabytes per second and the average is 20.5 megabytes per second.

The blue line we can in the graph shows the read performance of my hard disk. We can also see the CPU utilization in percentage.

how to check hard disk quality
how to check hard disk quality

We can also change some of the settings of this benchmark analysis. Just press the options icon mention in the first picture of the document we can see settings we can change. We can change the test speed time, if we can the test to be completer quickly we can just increase the time from options but it is expected that if we make the speed at the highest level if won’t give us some accurate results, so it is suggested not to make the speed at a higher level.
Please see the below picture for more clearance.

how to check hard disk transfer rate
how to check the hard disk transfer rate

How to check hard disk information with HD Tune

This part of the software provides us the information regarding the partiton of the hard disk. As you can see in below picture I have 3 done partitions of the hard disks, we can see the capacity, usage In percentage and some other information,

In supported features part of we can see which features are suported are which are not supported.

In the last part of the screen, we have the information regarding firmware version, serial number, capacity of the hard disk, my hard disk is of 1TB but I can use 930Gb approx.

how to check hard disk info
how to check hard disk info

how to check hard disk health with HD Tune?

This part of the application analyzes the hard disk and provides us the information about the health check of the HDD.

ID column shows which process is being measured, what’s it’s current value along with the worst value and the threshold hold value. Status shows the status of the process which was analyzed.

how to check hard disk health
how to check hard disk health

how to check hard disk bad sectors with HD Tune Error Scan?

This feature will scan the entire disk and it will let us know about the defects of the hard disk in the red blocks. If It’s green entirely then it means that our hard disk has no defects, and we don’t have to worry about the hard disk.

We can perform a quick scan of the disk also for that we need to mark the quick scan box icon, It will scan the entire disk in a minute and we won’t have to wait, but for better results, we shouldn’t do the quick scan as it may not be that much accurate.

Below is the snap after taking a quick scan of the hard disk.

how to check hard disk bad sectors
how to check hard disk bad sectors
  • Hard Disk:

The part which I highlighted below picture shows the hard disk which we analyzing if there is more than one hard disk we can select the hard disk as the one we need to test.

how to check hard disk before buying
how to check hard disk before buying

how to check hard disk temperature with HD Tune?

The second thing is the temperature we can set the threshold for the temperature when that is crossed the font color will change, we can also set the unit in which we want to have the temperature i.e, Celsius or Fahrenheit, or even both of them as I have selected.

how to check hard disk temperature
how to check hard disk temperature

Frequently Asked Questions (FAQ)

Is a 256GB SSD better than a 1TB hard drive?

Suppose we have a laptop with a 128GB or 256GB SSD instead of a 1TB or 2TB hard disk. A 1TB hard disk storage is equal to 8 times 128GB SSD, and similarly 4 times as much as a 256GB SSD.

You must also know about

hard drive definition | hard disk external | working of hard disk with diagram | internal hard disk | hard disk price | features of the hard disk drive | hard disk storage capacity chart | hard disk performance | internal hard disk | hard disk 500GB | the hard disk features pdf | benefits of the hard disk | types of a hard disk | hard disk definition and function.

Three ways to improve the performance of a hard disk include Disk caching, RAID, and file compression.
Prof. Fazal Rehman Shamil
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