The Complete Guide To Storage Devices

The Complete Guide to Storage Devices: Definition, Types, Examples, Uses, Applications, Advantages, Disadvantages etc.​

This article will provide you with all the basic information regarding the storage devices, their uses, advantages, disadvantages, applications, examples, and types too. 

So, stick to reading this if you want to get cleared all the basics on the topic of ‘storage devices’, their types, and sub-types too. Yes, you read it right! Isn’t it a great deal? So, without further ado, Let’s start reading… 

  • We will start by simply understanding some facts about ‘Computer Memory’ and ‘Computer Storage’. It often may create confusion for some of you. 
  • Memory can be said to be the storage area or a device which stores any kind of information or data, mostly known to be temporary and ‘volatile’. That means data gets erased when the computer is turned OFF, or the power supply goes OFF. 
  • The computer memory is mostly used to store urgently used data like some program instructions or currently running program files /applications. 
  • Due to this functionality, it allows faster access to data. It is also known as ‘Primary Storage’. This may have got your attention!
  • Apart from this, Storage is mostly considered to be non-volatile i.e., permanent and slower to access in comparison with Memory. These terms are not much different rather are the same in many ways.

In short, Memory can be referred to the fast and volatile technology, whereas slower and non-volatile technology is mostly referred to as Storage. Now that we have understood the meaning of storage, we can jump to more details about ‘Storage Devices’.

What is Storage Devices?

Storage Device’s is defined as the hardware developed for three principal purposes, first being the purpose of preserving our information which may include any files or even instructions, second is to fulfill the requirement of that data if any such situation occurred, and third to be the medium in transferring data to another location.

  • It is a piece of hardware used to save or carry any accessible data which may be for both short or long term use.
  •  It can be used inside the computer or from outside it as it is attachable, provided the computer has the particular hardware to support it. It is also known as ‘Storage Medium/Media’. 
  • Storage devices can store data from kilobytes(KB) to beyond petabytes(PB). They can store data in any type, like, audio, video, images, files, etc.. 

EXAMPLES:- Some examples of storage devices are:- Hard disk, RAM, USB, CD, DVD, and many more. 


Different uses of Storage Devices are:-

  • Used to provide easy and any time storage of data.
  • Provide quick access to stored data. 
  • Supports different types of data.
  • Provides data security through encryption. 
  • Data can be made portable with some types.


Storage devices can be classified into two types– Primary Storage Devices and Secondary Storage Devices, discussed below in detail, one by one.

types of storage devices


“A Primary Storage Device is considered as those devices which are made to save information regarding operating any application, program or activity in our computer or any electronic device i.e., to save that information which is needed in that very period, is called ‘Primary Storage Device’.

Like human memory, this hardware also resides always inside the ‘Brain’ of the computer, the CPU. It behaves as the main source of data storage for the computer.

It is just like the human memory that we have. Similarly, the computer has its memory or storage called Primary Memory/Storage, also known as ‘Main Memory/Storage’.” 

  • There are many types of devices used as primary storage for computers.
  • As, we cannot start any electronic device without booting the operating system(OS), so to save the OS or to make the computer operate, it needs to follow some instructions. Those instructions are to be saved somewhere.
  • So, primary storage devices are used as an internal memory of the computer so that it always remains with it, and to make use of it, even if the computer is not yet started. 
  • As earlier stated, it is like the human memory, it can be both volatile and non-volatile, in a way as humans are more likely to remember their names, credentials or any other most important memories, this becomes non-volatile memory and volatile is that memory which stores our day-to-day activities (not that important).
  • These devices are much faster to access and the access time per byte is in nanoseconds(ns) as they are nearer to the Central Processing Unit(CPU).

Let us understand different types of storage devices in detail.

types of storage


“Registers are that hardware component residing in the CPU which serve as one of the types of primary storage devices are utilized to store the instructions to run any computer program. They are also named as ‘Processor Registers’.” 

The data or instructions stored in the registers are very fast accessed. They have a very small limited storage capacity which in some bytes. These come in a range of bits such as 8-bit, 16-bit, 32-bit, 64-bit, etc..


  • Some examples of Registers are:- 
  • 8-bit registers:- AH, AL, BH, BL, CH, etc. 
  • 16-bit registers:- AX, BX, CX, DX, SP, BP, SI, DI, etc. 
  • 32-bit registers:- EAX, EBX, ECX, EDX, ESP, EBP, ESI, EDI, etc. 
  • 64-bit registers:- RAX, RBX, RCX, RDX, RSP, RBP, RSI, RDI, etc.

USAGE:- Different uses of Registers are:- 

  • Used to store data in the form of instructions or memory addresses of some variables to be used in the instructions. 
  • Helps in providing required program instructions before and after the execution. 
  • To evaluate or store the address of the next upcoming instructions after performing the current ones. Provides fast access to data. 
  • The efficiency of the computer may depend on the number of registers and operations performed using them. 

APPLICATIONS :- Applications of Registers are :- 

  • Data storage in digital form. 
  •  In the making of cache memory.
  •  In the manufacturing of digital chips like ROM, flash, etc.. 

ADVANTAGES :- Advantages of Registers are :- 

  • Much faster access to data than any other storage device. 
  • Execution of operations is also faster. 
  • Provide more control on computer programs. 
  • Instruction speed and size can be optimized using these. 

DISADVANTAGES :- Disadvantages of Registers are :- 

  • Limited size. 
  •  Little complex to use and understand. 
  •  Occurrence of unwanted values sometimes. 

TYPES :- Two types of registers are :- 

  1. General Purpose Registers:
  • Can store both, data or any memory address/location.
  •  Multipurpose registers.
  • Types:- Accumulator(AC), Data Register(DR), etc.. 

         2. Special Purpose Registers:

  •  Hold either data or memory address location, not both. 
  •  These include types:- Program counter(PC), Instruction Register(IR), Status Register, etc..


“Cache can be defined as that volatile type of storage component which stores short-lived data. Pronunciation of Cache is ‘kash’, also known by the name of ‘CPU Memory’.” 

  • Cache memory is used during the run-time. That means it stores that data which is to be used for performing the tasks or operations at that current time. 
  • It has very high-speed data as it is to be used more often. It is physically near to the CPU. 
  • The data blocks which are required to perform certain operations are transferred from RAM(which we will discuss further) to the cache whenever required.
  • These are faster than other storage media but slower than registers. You may have seen this term while going through the ‘settings’ of your browser, as it stores the data affiliated to the browsing of different sites. 
  • It keeps the data such as images, figures, or so related to that particular website you are browsing, already loaded in temporary storage, so if your internet connection gets interrupted, you can still load that site’s some data but for only some time. 
  • This is done by the cache. Cache comes in different levels as the L1 cache, L2 cache, L3 cache and more, each has different functions of their own. Cache has storage capacity in KBs.

EXAMPLES:-Some examples of Cache are:

  • D-RAM, MCD-RAM, on-CPUSRAM, etc..

USAGE:- Different Uses of Storage Devices are:

  • Used to lessen the average cost and time to access data. 
  • Used to perform small functions after turning ON the computer. 
  • Helps to increase the overall performance of data gathering.

APPLICATIONS:- Applications of the Cache are:

  • Software cache is used to store data related to browsing for faster loading of websites. 
  • Also used by apps for better and faster performance. 
  • Acts as a buffer between CPU and RAM.
  • Used in graphic cards for the smooth performance of complex operations and games.

ADVANTAGES:- Advantages of Cache are:

  • Less data access time, hence, data retrieval is faster.
  • Offline surfing of sites due to already saved pages. 
  • Stores data for further use which is to be executed in less time. 
  • Faster than RAM and ROM.

DISADVANTAGES:- Disadvantages of Cache are:

  • Less storage capacity. 
  • Expensive. 
  • A damaged cache can affect directly on the overall performance.
  • Updated pages of websites cannot be seen due to storing of previous pages in cache, hence, the old version gets loaded. 
  • Excess of cache can lead to occupying of the free available space.

TYPES:-There are three types of Cache:

  1. Direct Mapped Cache:- single line/block used for cache. 
  2. Fully Associative Cache:- data can be stored in any line/block of the cache. 
  3. N-Way-set Associative Cache:- any number of lines can be used for cache.

3. RAM:-

“RAM with expansion as ‘Random Access Memory’ is said to be a primary storage device made in the form of an electronic chip, which is used to store data for limited and instant requirements. 

Data stored in RAM is volatile. As the name suggests, it provides random hold on the data anytime stored in it.” 

RAM is responsible for faster performance and responses of the applications in a computer. The speed of data accessing from RAM remains in Megahertz(MHz). The storage capacity of RAM can be measured in Gigabytes(GB).

EXAMPLES:- Some examples of RAM are: Dual-Inline Memory Module(DIMM), Small-Outline DIMM(SO-DIMM), Double Data Rate(DDR), etc..

USAGE:-Different Uses of Storage Devices are:

  • Used to store programs for run-time operations. 
  • Used to store temporary files for urgent needs and faster functionality. 
  • Greater storage capacity RAM is useful for the fast and swift working of the device. 
  • Also used as a buffer. 
  • Used because of low power dissipation.

APPLICATIONS: Applications of the RAM are:

  • Used in usual operations while booting process for further loading of programs. 
  • Used in smart-phones, tablets, laptops, etc., for smooth functioning and loading heavy applications. Used in big computers and servers for better functioning and operation of heavy load programs and data.

ADVANTAGES:- Advantages of the RAM are:

  • Increases speed of the working of programs, hence, increase the efficiency. 
  • Supports multitasking. 
  • Consumes less power.
  • Faster retrieval of data.
  • Increases battery life.

DISADVANTAGES:- Disadvantages of the RAM are:

  • Expensive. 
  • Limited space. 
  • Volatile in nature.

TYPES:- There are two types of RAM:

1.Dynamic RAM(DRAM):

  • Mostly used as the main memory of computers.
  • Needs to be refreshed in every few milliseconds. 
  • Changes continuously. 
  • Asynchronous with some computer programs.

2.Static RAM(SRAM):

  • Holds memory until the power is supplied. 
  • Allows greater efficiency due to synchronization with computer applications. 
  • Expensive. 

Types:- SDRAM, DDR-SDRAM, etc..



Read-Only-Memory(ROM) is an electronic chip made to save the data with fewer changes needed in a non-volatile form. 

It is also one of the types of primary storage devices. Data can only be read from this chip, cannot be re-written on it. It is a non-volatile type of storage.” 

ROM stores that data which is either not required instantly or is to be used without any changes. BIOS( Basic Input/Output System) is stored on ROM. We can only read instructions from ROM. The storage capacity of ROM is only in a few Megabytes(MB).

EXAMPLES: Some examples of ROM are:

  • ROM Chip No. 3301, 1702 EPROM by Intel, MBM 2764 EEPROM by Fujitsu, etc..

USAGE:- Different Uses of ROM are:

  • Used to store some permanent instructions.
  • Used to update the firmware.
  • Helps in multi-gaming. 
  • Used to boot BIOS.

APPLICATIONS:- Some applications of ROM are below:

  • Firmware of micro-controllers.
  • Daily use electronic items like smart-phones, washing machines, microwave, etc.. 
  • Due to no requirements of any changes, also used in embedded systems. 
  • Electronic toys to run some saved programs like a type of a particular music or any movement.

ADVANTAGES:- Advantages of the Storage Devices are:

  • Non-volatile in nature. 
  • Cheaper than RAM. 
  • Provides permanent storage. 
  • More reliability than RAM. 
  • Uses less power. 
  • Helps in booting. 
  • No Updations, so static nature.

DISADVANTAGES:- Disadvantages of the ROM are:

  • Cannot be changed. 
  • Slower than RAM. 
  • Damage to some parts leads to the uselessness of the whole chip. 
  • Less storage.

TYPES:- There are three main types of ROM:

1.Programmable ROM(PROM):

  • Allows storage only once. 
  • Cannot be erased or re-written, if once written. 
  • Used in firmware or low-level programs.

2.Erasable Programmable ROM(EPROM) :

  • Non-volatile 
  • Erasable by using UV rays.

3.Electrically Erasable Programmable ROM(EEPROM) :

  • Non-volatile ○Used in smart cards. 
  • Data can be deleted by electrical signals but for limited times, about 10,000 times.


A Secondary Storage Device is a hardware created for three main functions, first is the purpose of preserving our information, the second purpose is to make that information long-lived so that it can be used anytime further if required, and third to be the carrier of our information while transferring it to another location. 

These are mainly external resources used for storing data in larger volumes as compared to primary storage devices. Data stored in these devices remain non-volatile.” 

  • Secondary storage devices are used to make preserved for a longer time. Like we humans use external media to support saving of our data or memories as in phones, notepads, diaries, laptops, etc., apart from our own memory, similarly, these devices help to do the same. 
  • Also, these devices are not necessarily to be kept always with the computer, only attached when needed. Data stored in these devices can be in any multimedia type e.g., audios, videos, images, etc.. 
  • Mostly, secondary storage devices are slower for data retrieval in comparison with the primary storage, as they are applied externally and contain a heavy amount of data. Let us study about the types of secondary storage devices in detail.


The term ‘Magnetic Storage Devices’ is referred to those devices which save our data in the form some patterns made by the magnetized particles on hardware like a disk or a tape. 

This means these devices reserve our data represented by these patters/imprints on a tape or a disk after kept under a magnetic field.” 

  • These devices have a large capacity of storage about from Gigabytes(GB) to Terabytes(TB).
  • These devices are very helpful in making data portable. 
  • The access rate of data is comparatively slower than primary storage devices.
  • User can read as well as write on magnetic storage devices.

EXAMPLES: Some examples of Magnetic Storage Devices are: Cassettes, Strips at the back of debit/credit cards., etc..

USAGE:- Different uses of Magnetic Storage Devices are:

  • To make data portable.
  • To store data in various formats. 
  • For storing data in large amounts as compared to primary storage devices. 
  • Recording analogue signals by using the process of magnetization.

APPLICATIONS:-Applications of the Magnetic Storage Devices are:

  • Music tapes, to store audio files. ○Movie tapes/disks. 
  • Process of analogue recording, for storing audio and video media in the form of continuous analogue signals.
  • Digital recording to record audio and video files in the form of binary code.
  • In hard drives as the main memory.

ADVANTAGES:-Advantages of the Magnetic Storage Devices are:

  • Cheap in cost. 
  • Small and thin in size. 
  • Appropriate for both on/off-line storage of data.

DISADVANTAGES:-Disadvantages of the Magnetic Storage Devices are:

  • Corruption of some parts affects the whole storage device.
  • Can easily be damaged. 
  • Slower data access rate in comparison to main memory. 
  • Certain types do not have much storage space. 
  • More likely to get errors.

TYPES:-Three main types of Magnetic Storage Devices:

1.Magnetic Tape:

  • Type of magnetic storage device used to record and play multimedia files. 
  • Storage capacity started in MBs and now in TBs.

2.Floppy Disks:

  • It is Also called diskettes. 
  • Thin, flexible and magnetized. 
  • Can read as well as write data on it. 
  • Uses Floppy Disk Drive(FDD) to operate. 
  • Also used to store OS. 
  • Storage capacity started from KBs, now available in 1.44 MB.

3.Hard Disk Drive(HDD) :

  • Can be used as an external or internal storage device. 
  • Mostly used/attached with laptops, PCs, etc., to store any type of data. 
  • Also used to store OS or other software programs.

Optical Storage Devices:

Optical Storage Devices are said to a form of storage media which contain impressions of the information which is to be preserved with the help of a technique of rebounding of light rays. 

Data imprinted on these devices are non-volatile i.e., permanent. Reading and writing of data are done with the help of lasers on these devices, hence, also known by the name of ‘Optical Media’.”

  • Light beams are used to save data on the surface of these devices.
  • Different storage capacities can be formed by using different colours of light waves of different wavelengths. 
  • Using colours having small wavelength can result in storing more data and vice versa. These devices are re-writable. 
  • The durability of these devices is more in comparison with magnetic tapes. 
  • Data access rate which is about 100ms-1s, is slower than hard drives. Also, storage capacity is lower, which is about in MBs or few GBs.

EXAMPLES:Some examples of Optical Storage Devices are:

  • CD-R, DVD-R, LG 14x Blu-ray Re-writer, Asus 24x DVD-RW Optical Devices, etc..

USAGE:-Different uses of Optical Storage Devices are:

  • Large shelf life for up to 50 years. 
  • High portability.
  • Used for random access of data. 
  • Can store a variety of data. 
  • Used when multiple users have to access the same volume of data at the same time.

APPLICATIONS:-Applications of the Optical Storage Devices are:

  • Transporting the data/media files of any types.
  • Retaining business records.
  • Transferring the OS or some software programs to other devices.

ADVANTAGES:-Advantages of the Optical Storage Devices are:

  • Supports large on-line capacity. ○Inexpensive. 
  • Multi-user capability.
  • Small physical size.

DISADVANTAGES:-Disadvantages of the Optical Storage Devices are:

  • More prone to scratches. 
  • Slow access. 
  • Particular hardware is required to support these devices.

TYPES:-Six types of Optical Storage Devices are:


  • Read-only format ○Cannot write on these. 
  • Capacity – 700-800 MB.


  • Read-only format.
  • Non-writable.
  • Capacity – 4.7 GB.


  • Writable. 
  • Capacity – 4.75 GB.

4.Recordable Media:

  • Data can be recorded and re-written on these types of disks. 
  • Types – CD-R, CD-RW, DVD-R, DVD+R, DVD-RW, DVD+RW(RRecordable, RW- Re-writable).

5.Removable Disks(RDX) :

  • Removable hard disks. 
  • Capacity – in TBs.

6.Write-once read-many (WORM) :-

  • Once written, cannot be re-written. 
  • Can be read several times. 
  • Capacity – from MBs to GBs, depending on physical features.

7..Blu-Ray Disks:

  • Stores huge amounts of data. 
  • Capacity – 20 to 50 GBs. 
  • Due to shorter wavelength, blue light is used to store more data instead of red light(which are used in other Compact Disks).


“Flash Storage Devices devices can be described as those media which serve the purpose of preserving generous amounts and variety of data which can be also be transported and shared easily.” 

  • These devices use memory called ‘Flash Memory’ used to store huge amounts of data which can be up to TBs.
  • Data including multimedia data or software programs can easily be transported to other devices or even places. 
  • These devices can be re-programmed, erased or re-written. Different types of data are supported here.

EXAMPLES:-Some examples of Flash Storage Devices are:

  • Memory cards, BIOS chips, memory sticks used in digital cameras, USB, etc..

USAGE:-Different uses of Flash Storage Devices are:

  • Storing variety and huge amounts of data. 
  • Transport data from one device to another smoothly.

APPLICATIONS:-Applications of the Flash Storage Devices are:

  • Memory chips in digital cameras. 
  • Devices used for Global Positioning System(GPS). 
  • Electronic devices, such as phones, mp3 players, T.V. set-top boxes, etc.. 
  • For devices used in military, security and embedded systems.

ADVANTAGES:-Advantages of the Flash Storage Devices are:

  • Data retrieval is faster. 
  • Smaller physical size. 
  • Less power usage.
  • Less exposed to damage. 
  • Cheaper than main memory.

DISADVANTAGES:-Disadvantages of the Flash Storage Devices are:

  • Easy to loose these due to smaller size. 
  • Expensive than hard disks. 
  • A special type of program used for protecting against early wearing out. 
  • Does not support multiple reading of the same data.

TYPES:-There are five main types of Flash Storage Devices:

1.Storage Array:

  • Combination of many disk drives. 
  • Provides more capacity than a few file servers. 
  • Supports multiple accessing of data by many servers. 
  • Also known as Disk Array or Disk Storage Array.

2.Solid State Drive(SSD) :

  • More advanced than hard disk drives. 
  • Provide more speed than hard disks. 
  • Do not have any moving parts. 
  • Less delay in performing operations.

3.All-Flash Memory:

  • Very low delay in performing instructions or operations.
  • Advanced in SSD in performance.

4.Non-Volatile Memory Express(NVMe)Storage :

  • Supports multiple access requests on single data. 
  • Helps increase the performance of the system and its applications. 
  • Comprises of new protocols for accessing high-speed data.

5.Hybrid Flash Storage:

  • A mixture of Hard Disk Drives(HDD) and Solid State Drives(SSD).


Cloud Storage, in reality, can be described as non-physical storage media granted as a service by some third-party companies, made available for the general public, though, physically the data is stored on huge servers owned by those storage service providing companies. 

This data storage facility requires an internet connection to be availed.” 

  • Here, the ‘cloud’ refers to this internet-based untouchable data storage for the customers and can be accessed from anywhere at any time. 
  • No need of buying extra hardware for storing data, we can buy online storage which is highly scalable, i.e., we can increase the storage capacity we own by buying more storage from these companies at any instant of time, whenever needed and of different capacities. This type of data storage is administered by them. 
  • This type of storage service is available all around the world and supports various types of data. Also, it allows data to be stored in the off-site location. The storage capacity of cloud storage is beyond Exabytes(EB).

EXAMPLES:-Some examples of Cloud Computing Storage are:

USAGE :-Different uses of Cloud Storage are:

  • Very efficient in maintaining back-up of our data. 
  • Scalability is very high. 
  • Instant and easy access to our whole data on the cloud. 
  • Can store unlimited amounts of data using the cloud storage service. 
  • Data can be accessed anywhere and anytime using internet.

APPLICATIONS :-Applications of Cloud Storage are :

  • Data back-up.
  • Sharing of data. 
  • Analyzing Big Data. 
  • Recovery of data in case of any disaster.

ADVANTAGES :-Advantages of Cloud Storage are :

  • Everywhere access support. 
  • Storage capacity can be increased easily. 
  • Easy data management and tracking. 
  • Security support. 
  • Affordable.

DISADVANTAGES :-Disadvantages of Cloud Storage are :

  • Risk of unauthenticated and unauthorized access to data. 
  • Hacking and virus attack threats.
  • Security sometimes not updated, can lead to serious data damage. 
  • Delay in data retrieval. 
  • Requirement of internet connection in the process.

TYPES :-The main types of Cloud Storage :

1.Private Cloud :

  •  Remains within the data owner’s network. 
  • A private connection is set up between the owner of the data and the stored data. 
  • Used by banks or companies for managing and storing their confidential data.

2.Public Cloud :

  • Type of connection set up over the internet. 
  •  Managed by the cloud storage service provider. 
  •  Accessed by any device like smart-phones, computers, etc., having internet connection. 
  •  Can be upgraded or downgraded.

3.Hybrid Cloud :

  • Combination of Private and Public Cloud Storage.
  •  Provides facility too give choice to customers between the two depending upon the sensitivity of the data of the customer.


Here we discussed everything about what is storage devices, types of storage devices, its Uses, applications, concepts etc. Hope you liked this article.

Hope you easily understood the concept of “Storage Devices”, but if you have any queries related, do not hesitate to ask in the comment section. 

Thanks for reading!

Ritika Bharat
Ritika Bharat
Chief Editor & Technical Content Writer at BrainyWit

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