5 types of storage devices- All You Need To Know

5 types of computer storage devices
5 types of computer storage devices


Storage devices are very important for todays life style. At each and every moment we are using different types of storage devices. 

Starting from our mobile to computer and TV, everything is fitted with some kind of storage device.

So today we will learn about 5 types of computer storage devices. How  we keep our important data safe in our computer with the help of these storage devices.

When we listen the word of data, in our mind we make a picture of disk drives.  These drives are mainly called Storage Devices.

In our day to day life we come across different kinds of Storage Devices like CD, DVD, pen drives, hard disk etc.

We can store a different quantity of data as per size of the storage device.

Different sizes of storage devices are as follows:

Type of storage device Capacity
CD 700 MB
DVD 4.7 GB
Pendrives 1GB TO 128 GB
Hard disks/drives 256 GB TO 12 TB

In computer algorithm everything is calculated by binary system. In binary system the following formulae work.

1Byte= 8 Bit

1KB= 1024 Byte

1 MB= 1024 KB

1GB= 1024 MB

1TB= 1024 GB

KB- Kilobyte, MB – Megabyte, GB- Gigabyte, TB- Terabyte.

From above description we know that TB is the largest unit and bit is smallest unit. When we will purchase any storage device can see its specifications related to capacity of the device.

Storage devices are basically divided into two types.  One type is called internal drives and another one is called external storage devices.

Internal Storage is used inside the computer to work like it’s memory.  Whereas External Storage is basically used for storing our valuable data.

In internal storage, computer uses data read and writing method to save its internal programs and other handy information we are working with the help of computers. Like RAM and ROM.

RAM (Random access memory) 

RAM is a volatile memory which is used by computer as work on memory. 

Every time we are switching on the system it gets activated and starts its job of read and writing. 

But when we switch of the system all the data we are working are getting erased by computer. For more knowledge of RAM, visit my previous blogs.RAM

In lame language it is a white board where we write and clean every time before and after each switching on/off of computer. 

So we have to save our projects/ files during working to avoid loss of data. When we save the data it goes to ROM.

ROM (Read only memory) 

It is a nonvolatile memory which is used by system to keep the data safe after switching off of computer. 

All our work, files, songs, videos, etc are getting saved in to this device. Computers operating system is also loaded in this storage medium. 

At the time of starting computer operating system from this device is getting loaded to RAM and then the system boots itself. 

So it is very much important part of our computer. It is also known as Hard disk drives or HDD.

External storage devices

CD (Compact discs) , DVD (Digital versatile discs) , Pen drives, External Hard disks  are commonly used as our external storage.

CD (Compact discs)


These are the circular discs of very less capacity about 700 MB.

These are of two types one is called CD-R (CD – Read only) and CD-RW (CD- Rewritable). 

In CD-R we can not over write any data but in CD-RW we can rewrite by erasing previous data and reuse it.

Most of a CD is made from a tough, brittle plastic called polycarbonate

Sandwiched in the middle there is a thin layer of aluminum. Finally, on top of the aluminum, is a protective layer of plastic and lacquer.

The data on a CD is encoded in the form of small pits and bumps in the track of the disc.

DVDs (Digital versatile discs)


Digital versatile discs are also circular discs of very thin plate like CD. But the storage capacity is high upto 4.7GB.

These are of two types one is called DVD-R (DVD – Read only) and DVD-RW(DVD- Rewritable).

 In DVD-R we cannot over write any data but in DVD-RW we can rewrite by erasing previous data and reuse it.

DVDs are also created with the same technology as of CDs. A DVD disk has several layers, which are made of plastic

Thickness of DVD is about 1.2 millimeters. An injection used on a polycarbonate plastic leads to the creation of microscopic bumps.

The data on a DVD is encoded in the form of small pits and bumps in the track of the disc.

Pen drives


These are also called USB flash drives. It came to the market from the year 2000 onwards. 

Most of the pen drives in the starting phases was from 4 GB. 

But today you can find flash drives of about 2TB capacity easily in the market.

It comes with the chip technology and write erase cycle of approximately 1,00,000 cycles.

All USB drives are comprised of five essential components. These five components are:


  1. Standard USB Plug- It connects drive with external interphase
  2. USB Mass Storage Controller- It controls Drive
  3. NAND Flash Memory Chip- It is the storage area
  4. Crystal Oscillator-
  5. Cover- It protects the drive
  6. LED- to show switching on/off

HDD (Hard disk drives)


HDD really changed the way we think about computers.

It is invented over 50 years ago and in market for common use after year 1980s.

The main parts of a HDD are as follows


(i)   Actuator: It moves the read-write arm. 

As their name suggests, these are simple electromagnets, working rather like the moving coils that make sounds in computer.

They position the read-write arm more quickly, precisely, and reliably than stepper motors and are less sensitive to problems such as temperature variations.

(ii)  Read-write hand:  It swings read-write head back and forth across platter.

(iii) Central spindle: It allows platter to rotate at high speed.

(iv) Magnetic platter:  It stores information in binary form.

(v)  Plug connections : It links hard drive to circuit board in personal computer.

(vi) Read-write head: It is a tiny magnet on the end of the read-write hand.

(vii) Circuit board:  It controls the flow of data to and from the platter.

(viii)      Flexible connector: It carries data from circuit board to read-write head and platter.

(ix) Small spindle: It  allows read-write arm to swing across platter.

HDDs are worked on principles of magnetism. It is made of large shiny, circular, plates of magnetic materials called platters. 

These platters are disks made from glass, ceramic and aluminium which is coated with a thin layer of metal that can be magnetized or demagnetized.

It is again sub divided into internal and external storage HDDs.

Internal HDDs are used inside the desktop PCs or laptops and are the main source of system memory in computer.

External HDDs are mainly used to store data outside the computer. It is the same HDD but with a USB port for connecting computer and a casing to safeguard it from dust and accidents.

SSD (Solid state Drives)


These are the drives which are created mainly using the flash memory technology. 

SSDs typically use  flash memory chips instead of spinning magnetic platters. 

Computer makers gradually moving away from hard drives, to SSDs.

These flash chips are of a different type than the kind used in USB thumb drives, and are typically faster and more reliable. Power consumption is minimal to zero at the time of use. 

Less sound by the drive and computer. Faster uploading and downloading of data from SSD.

Main Parts of SSD are:


(i)   NAND Flash memory chips- It stores data

(ii)  SSD Controller- It controls the data flow from flash memory chip

(iii) SATA and power supply- It connects with circuit board and supply power to the drive

(iv) Config and general I/O- It helps in configure of  the SSD

SSDs are also subdivided into two parts internal and external.

Internal SSDs are used for internal storage of the system and configured with mother board or circuit board as system memory/storage.

External SSDs are used for storing of data outside the computer.

Due to heavy cost of the SSDs. External drives are not desirable as one can find a more capacity of HDD in the same price.


As we know all about different storages we are using to store our data. The last two HDDs and SSDs are most important for computer.

If we compare HDDs and SSDs, than a computer with SSDs can perform faster by retrieving and uploading data faster than HDDs.

But a computer with HDDs will be cheaper and can store a large amount of data with higher storage capacity. The main reason behind is SSDs are costlier than HDDs. 

In same price we can get higher capacity of HDDs than SSDs.

Fastness of a computer depends on the type of Drive we have used inside it. As SSDs are more costly but faster than HDDs.

Computer manufacturers are opting for hybrid drives inside the computer. 

In Hybrid drives both SSDs and HDDs are fitted for smooth faster action and storing large amount of data than the normal computer.

So today we know about 5 types of computer storage . For more knowledge on HDD and SSD go through my other blog

Which is better HDD or SSD 

Please like and share my blogs.

Have a great day!


Please enter your comment!
Please enter your name here