Types of Computer Storage Devices and their Uses

Any kind of hardware that stores data and instructions on the Computer are called Storage Devices. Today we are going to discuss how many Types of Computer Storage Devices are there and what are their Uses & Functions. Computer Storage is also called Computer Memory.

Before we start, let me answer the most asked Query:

History of Computer Storage Devices:

These days, there are several Types of Computer Storage Devices that allow us to store and transfer data easily. But do you know what was the first storage device? It was Paper. 

In the Olden Days, people used Punch Cards to store data. Those Punch Cards were not even able to hold data in Kilobytes. Therefore, they invented drum memory, but it was huge in size and was capable of storing only a few Kilobytes of data.

Then comes Tape Drives, which were far better than the previous inventions. As time passed by, scientists were able to build a Hard Drive. But, unlike the Hard Drive we use today, the initial variant was huge and was capable of holding just 5 MB of data. Thankfully, with the help of modern technology, they were able to reduce the size of the hard disk.

Paper Storage technology is still utilized in this modern era in the form of OMR (Optical Mark Recognition)

How Computer Memory is Measured?

Computer Memory is measured in Bits or Bytes. The Bit (Binary Digit) has a binary value of 1 or 0. These Bits combine together to form Bytes, Kilobytes, Megabytes, and more. You might get shocked knowing that 1MB contains 1000000 Bits.

Here is how you can measure Computer Memory:

• 4 Bits make a Nibble
• 8 Bits form a Byte. 
• 1024 Bytes form a KB (Kilobyte)
• 1024 Kilobytes form an MB (Megabyte)
• 1024 Megabytes is equal to 1 GB (Gigabyte)
• 1024 Gigabytes form a TB (Terabyte)
• 1024 Terabytes from a PT (Petabyte)

For now, our regular Computers support up to 15 Terabytes of Memory. The highest capacity of hard disk in 2021 is 15 TB manufactured by Western Digital. In the future, you may also see hard disks with Petabytes (PB), Exabytes (EB), Zettabytes (ZB), Yottabytes (YB), Brontobytes (BB), and Geopbytes (GPB). 

When I was a child, it was hard to imagine a hard disk with 1 TB of capacity. And yet, we are able to use Terabytes of Hard Disk on our Computer. As information technology is growing at an exponential rate, it won’t be long till we get to see hard disks with a Storage Capacity in Petabytes. 

What are the Types of Computer Storage Devices?

Generally, there are two types of Computer Storage Devices. Those are Primary Memory and Secondary Storage Devices.

Primary Memory (Primary Storage Devices of a Computer):

Primary Memory is used by the CPU to store/collect data and information. Whereas, Secondary Storage Devices are used to store data permanently and are accessed by the user. The Primary Memory Devices are always placed close to the CPU. Moreover, the primary memory devices stores a tiny amount of data, when compared to the Secondary Storage Devices.

Primary Memory is further divided into RAM and ROM. Besides that, we also consider Cache Memory and Registers as Primary Memory. However, Cache and Registers are placed inside the CPU itself.

Let’s discuss each Primary Memory in detail.

1. RAM (Random Access Memory)
   • SRAM (Static Random Access Memory)
   • DRAM (Dynamic Random Access Memory)
2. ROM (Read Only Memory)
   • PROM
   • EPROM
   • EEPROM
3. Cache Memory
   • L1 (Level 1)
   • L2 (Level 2)
   • L3 (Level 3)
4. Registers

1. RAM:

RAM (Random Access Memory) is called the Primary Memory or Temporary Storage Device. The RAM is installed on the Computer’s motherboard. Also, RAM requires constant electrical power to store data. Whenever the power is lost, the data in the RAM will be erased. That is why it is called a Temporary Storage Device.

RAM is the most important type of Computer storage device. When the CPU is running a program, it obtains the data from the RAM. If the RAM contains all the required data, then the performance will be fast.

Simple Example: 

First, you need to know that a CPU can access data from RAM more quickly because it is located near to the CPU on the motherboard. Whereas, the hard disk is located far from the CPU and connected with external cables. Therefore, it takes more time for the CPU to collect data from the hard disk.

Suppose you run MS Word, which is installed/stored on your Computer. The CPU stores all the data related to MS Word in the RAM. Let’s assume the MS Word application takes around 200-300 MB of RAM to run, and you have 1 GB RAM. Hence, the program runs faster, without any lags. 

Now suppose, you run the Adobe Premier app, which required 2 GB of RAM. As you have only 1 GB of RAM, the CPU needs to collect the remaining data from the Hard Disk, which slows down the process and performance.

Therefore, the solution is to have 2GB or 4GB RAM for that program to process smoothly. Also, having a faster hard disk like SSD or M.2 instead of HDD can speed up the process a little bit.

Note that it is only an example to help you understand the concept. The values used in the above example are entirely random. 

There are two types of RAMs. That is DRAM and SRAM.

-> DRAM (Dynamic Random Access Memory):

D-RAM needs to be recharged constantly to maintain its data. Also, the CPU cannot access the data in it while it’s refreshing. However, it is cheaper than DRAM. 

-> SRAM (Static Random Access Memory):

Unlike DRAM, Static RAM does not need constant recharging. Comparatively, S-RAM is faster and expensive than DRAM. Besides that, the CPU does not need to wait to access data from SRAM.

RAM comes in various sizes, starting from 256 MB to 32 GB. The number of RAMs you can install on a computer depends on the motherboard. A motherboard can have 2-8 slots for installing multiple RAMs.

2. ROM:

ROM (Read Only Memory) is another type of Primary Memory in the Computer. The ROM is a chip integrated into the motherboard. ROM stores only essential system data, which cannot be deleted or modified by the user. 

Now, you might be wondering what kind of system data does a ROM store. Have you ever noticed when you delete the entire PC while resetting or formatting, you can still access the BIOS settings. It is because the BIOS firmware is pre-installed in the ROM. 

Unlike RAM, ROM is a Non-Volatile memory that stores the data even when there is no power supply.

There are three types of ROM:

-> PROM (Programmable Read-Only Memory)

As the name suggests, the data in PROM is Read-Only, and you cannot edit or delete it. 

-> EPROM (Erasable Programmable Read-Only Memory)

The Erasable Programmable Read-Only Memory is erasable by using ultra-violet rays.

-> EEPROM (Electrically Erasable Programmable Read-Only Memory)

The EEPROM is an Electrically Erasable Programmable Read-Only Memory, which we can erase and upgrade using special programs.

3. Cache Memory:

The CPU stores frequently used or essential data in the Cache Memory. Cache Memory has three layers that are Level 1, Level 2, and Level 3. In the olden days, manufacturers used to place the Cache Memory on the motherboard, but now they come integrated inside the CPU. 

Cache Memory is a vast topic, so we suggest you check out our article on What is a Cache Memory. 

4. Registers:

Registers are another Type of Computer Storage Device used by the CPU to perform operations. Whenever you send a request to the CPU, it gathers all the data and information in the registers and executes the program. The data is removed after the task is complete. Moreover, the Registers come pre-installed inside the CPU, and they are faster than Cache Memory & RAM. 

Registers are further divided into several types, that are

• Data Register (DR)
• Memory Data Register (MDR)
• Memory Buffer Register (MBR)
• Program Counter (PC)
• Accumulator (AC)
• Instruction Register (IR)
• Memory Address Register (MAR)
• Input Register
• Output Register

Secondary Storage Devices of a Computer:

Secondary Memory Devices are slower compared to Primary Memory Devices. But, they can store vast data permanently and also allows users to transfer data. Secondary Storage Devices are also one of the important components of the Computer. Almost all Secondary Devices are Non-Volatile. Therefore, the user data is stored safely in them.

Secondary Storage Devices work on different data storage technologies. Based on their mechanism, they are divided into three types. Let’s talk about them one by one.

1. Magnetic Storage Devices
   1. HDD (Hard Disk Drive)
   2. FDD (Floppy Disk Drive)
   3. Magnetic Tapes
2. Optical Disks
   1. CD (Compact Disc)
   2. DVD (Digital Versatile Disk)
   3. BR (Blu-ray Disc)
   4. HVD (Holographics Versatile Disk)
3. Flash Memory
   1. SSD (Solid State Drive) & M.2
   2. Pen Drives
   3. Memory Cards

1. Magnetic Storage Devices:

Magnetic Storage Devices are Non-Volatile Devices. It means the data stored in the devices is permanent. We have already discussed that RAM is a Volatile Memory, which stores data only until the power supply is on. Whereas, Magnetic Storage Devices like Hard Disk and Floppy stores data permanently. 

-> HDD (Hard Disk Drive): 

A hard disk contains a Spindle that holds rotating disks called Platters. These Platter Disks are coated with Magnetic Material that holds the data. The Magnetic Head on the hard disk is responsible for reading and writing on the hard disk. 

We have already discussed the History of different types of Computer storage devices. The Hard Disks used to be very massive in size and stored very little data. Thanks to the growing technology, now we have smaller hard disks that hold a large amount of data. The latest generation hard disks can store data for more than 25 years.

PATA & SATA Hard Disks:

In older PCs, you will find PATA Hard Disks. The Hard Disks were connected to the motherboard through PATA (Parallel ATA) cable. These cables were wide but slow. The Parallel ATA was used to transfer data in the Parallel technique, due to which the data transfer speed was around 16MB/Sec. 

Therefore, a new type of cable was developed, called SATA (Serial ATA). Serial-ATA cables are small and much faster than PATA. You need to make sure you have a SATA type of hard disk and motherboard. These days, both HDD and SSD use SATA cables.

The Magnetic Hard Disk Drives are further divided into three types.

That is 

• 3.5-inch Internal Hard Disk Drive 
• 2.5-inch Internal Hard Disk Drive
• External Hard Disk Drive

What Is the Difference Between 2.5 & 3.5 Hard Drives?

There is no difference between the 2.5 inches & 3.5-inch hard disk drives, except for their size. Basically, the 2.5-inch hard disk drive was developed to place in laptops. 

The External Hard Disk Drives work on the same mechanism. The only difference is, it has a plastic coating for protection, and you can connect it through the USB. The External Hard Disk Drives are slower as well as expensive than Internal Hard Disk Drives. The other advantage of having an External Hard Disk Drive is you can backup or transfer more data. 

A new Computer storage device called SSD (Solid-State Drive) has emerged in the market, which is trying to replace the magnetic hard disk drive. It is a Flash Memory Type of Drive, which will be discussed later in this article.

-> FDD (Floppy Disk Drive):

Floppy was the first portable storage device, introduced in the year 1971. They are lightweight, small in size, and easy to carry. The Floppy Disk uses the same magnetic disk technology as the hard disk. Programs and files used to be very less in size those days. Therefore, the size of the Floppy Disk Drives was also less.

The First Version of Floppy Drive was 8-inch long with a storage capacity of 80 KB. Eventually, the size of the Floppy Disks was reduced to 3.5-inch, and its storage capacity extended to 1.44MB. Floppy Disk Drive was a revolutionary invention that ran for several years until Optical Disks & Flash Drives came into existence. 

-> Magnetic Tapes:

Though Magnetic Tapes works differently than Hard Disk Drives, they use the same mechanism. The Tapes or Cassettes has a string, which is coated with magnet material. That’s how the Tapes store data in the olden days. 

Examples of Magnetic Tapes are Camera Roll, Films, Audio Cassettes, DVR Video Cassettes, etc. The Magnetic Tapes hold the data in serial order. That is why, in audio cassettes, you need to forward through number 1 and number 2 song to get to song number 3.

2. Optical Discs:

It stores data in the digital form by using low-efficiency lasers. That is why we often use the word Write, instead of copy, when talking about optical disks.

Though the Optical disks were able to store much more data than Floppy drives, they had significant drawbacks.

The primary drawbacks of Optical Disk are:

• It is very sensitive. It could easily break into pieces if not carried carefully.
• A single scratch on the surface of the Optical Disk can cause data loss.
• Recordable Optical Disks doesn’t allow you to delete or edit existing data once written. (However, Re-writable Disks lets you wipe the disk entirely and add new data.)

-> CD (Compact Disc):

The Compact Disk has a storage capacity of 700MB. Previously, the CDs would allow you to write the data only once. It was not possible to erase or modify the written data. Moreover, it wasn’t even possible to write data to a previously used CD even if there is an empty space. 

For Example: 

Once you record 100 MB of data in a CD-R disc, you cannot add more data again even if there is 600 MB left in the disc.

There are different types of CDs:

• CD-ROM (CD-Read Only Memory): You can only read the content in the disc but cannot write.
• CD-R (CD-Recordable): You can record (or write) data into this type of compact disk only once. Though, you can read it infinite times. 
• CD-RW (CD-ReWriter): As the name suggests, you can write data multiple times on this disk. You can either add new data to the existing data or wipe out the entire disk and write new data.

-> DVD (Digital Versatile Disc):

After a few years of creating CDs, the manufacturers came with an advanced optical disk storage device. DVDs have the same dimension as CDs but can hold up to 4.7 GB of data. 

Different Types of DVDs:

• DVD-R, DVD+R (DVD-Recordable): DVD-R is the older version of DVD and DVD+R is the latest version. It is similar to CD-R, as the DVD is only recordable once. The only difference between these two is the compatibility issue. DVD-R may not be compatible with the latest Drives. Similarly, if you had an old PC, DVD+R may not be compatible with it.
• DVD-ROM: The DVD-ROM only lets you read the data, but not write.
• DVD-RW, DVD+RW (DVD-ReWritter): These ReWritable Versions of DVDs allows you to write data to the disc multiple times by erasing older one. 

-> BRD (Blu-ray Disc)

Blu-ray is the third generation of optical disks. Blu-ray uses the advanced technology of blue-violet rays so that it can have a shorter wavelength and store more data. While CD’s and DVD’s have a single layer, Blue-ray discs can have 3-4 layers. Moreover, each layer of Blu-ray disc can store up to 25 GB of data, which means a triple-layer blue-ray lets you store around 75 GB of data.

-> HVD (Holographics Versatile Disk)

It uses collinear holography by collimating red and green lasers. Even though the size of HVD is small, it has the ability to hold data in Terabytes.

3. Flash Memory:

The Era of Floppys and Disks came to an end after the introduction of Flash Drives in 1980. Flash Drives come in many forms, which are SSD, Pen Drives, Memory Cards, SD Cards, and more. Flash Drives do not have any moving parts, which makes them fast and more reliable. 

->SSD (Solid State Drive):

SSD is one of the Types of Computer Storage Devices. As we discussed earlier in this article, SSD uses the Serial-ATA type of connection. It is much faster than HDD, but also expensive. Solid-State Drives sizes about 2.5-inch and used as Internal Storage Devices. 

In 2021, the latest HDD can store up to 15 TB, while the highest capacity of SSD is only 4 TB. Solid-State Drives of 256GB will cost the same as 1 TB Hard Disk Drive. The SSD is recommended for gamers, as it will reduce the loading time. You can also install Windows on SSD to speed up the booting process by five times. 

The SSD is further divided into two types. That is:

• 2.5-inch disk
• M.2

SSD M.2:

The M.2 stands for Mini Version of SATA 2.0. Unlike the 2.5-inch SDD, M.2 is directly inserted into the motherboard port. M.2 drive looks like a RAM chip, which is even faster than the 2.5-inch SSD disk. As you can see in the above pic, the M.2 Drive slot is located beside the PCI port (where we insert Graphics Card).

We have further discussed the difference between M.2 Vs SSD Vs HDD Vs SSHD in another article.

->Pen Drives:

Pen Drives are another type of Computer storage device that helps you copy and transfer data from one PC to another. Pen Drives comes in several variants from 1GB to 256GB (like 1GB, 2GB, 4GB, 8GB, 16GB, 32GB, 64GB, 128GB, and 256GB). These are the size of a finger, lightweight, and portable. 

The PenDrives may not be faster than HDD and SSD, but they are much faster than the Floppy Drives and Optical Drives. They are also very affordable. Moreover, you can even make it a bootable USB drive and run Windows on a PC without HDD or SSD. 

-> Memory Cards:

The Memory Cards are sub-divided into three types. These Memory Cards are rarely used on a Computer. They are made for Digital Cameras and Mobile Phones. Most laptops have a Memory Card slot on them, which is useful to transfer data from other devices to the Computer. 

The Three Types of Memory Cards are:

• SD (Secure Digital) Cards: Comparitively Large in Size. Used in Digital Cameras.
• Mini SD: Previously used in mobile phones, but got replaced by the micro version
• Micro SD: Mostly used in Mobile Phones, rarely in other devices. 

Internal & External Storage Devices:

We can also differentiate the Types of Computer Storage Devices as Internal and External Devices.

Internal Storage Devices:

In simple words, the devices that are placed inside the Computer cabinet are called Internal Storage Devices.

Examples of Internal Storage Devices are: 

• RAM
• Internal Hard Disk
• SSD
• M.2
• ROM

External Storage Devices:

The Storage Devices that can be connected through USB, and not fixed inside the Computer are called External Storage Devices.

Examples of External Storage Devices are: 

• External Hard Disk
• Pen Drive
• All the Optical Disks

Additional Content:

SSHD:

Solid State Hybrid Drive is a mix of both HDD and SSD. It has a Magnetic Disk as well as Flash Drive. We will discuss the differences between SSHD Vs SSD Vs HDD Vs M.2 in another article.

Portable Storage Devices:

Except for the Internal Hard Disk Drive, all the secondary storage devices can be considered as Portable Storage Devices.

Cloud Storage:

Cloud Storage is not a Type of Computer Storage Device, but it’s a new technology that might replace secondary storage devices in the future. You can upload files to cloud storage and access them from any device from anywhere. 

Besides that, Cloud Storage is the safest form of storage. Several users have lost their important data in the past due to hard disk failure and damage. Therefore, cloud storage helps you back up important files in the server, which you can restore easily at any time. 

We will discuss more on cloud storage in another article. 

How to find what Type of Computer Storage Devices you have?

If you have a Desktop PC, then you can easily open the cabinet and see whether you have an HDD, SSD, or M.2. But, if you are using a laptop, it’s not recommended to open up your laptop. Instead, there is a simple way to check what types of Computer storage devices you have.

• Type Run in the Start Search bar and open the tool. You can also use the shortcut Win+R.
• Here you need to type the command dfrgui and click ok.
• In the Media Type column, you can see if your PC has a Hard Disk Drive or Solid State Drive, or Both.

How to Detect Storage Devices Capacity on your Computer?

There are several ways to detect the capacity of the storage devices on your computer.

Method 1:

• Search for Device Manager in your start menu, and open it.
• You will find all the storage devices on the Computer. (Novice users may find it hard to spot the storage devices in there. So, you can follow Method 2 or Method 3.

Method 2:

• You can open My PC, and count the capacity of all your drives to find out the storage capacity.
• Right Click on the My PC icon on the desktop, and go to properties. There you will find the RAM capacity.
• Next, open the Task Manager from the Start menu or by using the short key Alt+Ctrl+Delete.
• Go to the Performance tab, where you can see both the RAM and Cache Memory Storage Capacity.

Method 3:

This is the simplest and most efficient way of finding all the Computer storage devices on your PC.

• You can download and use the third-party app called CPU-Z by CPUID.

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Frequently Asked Queries:

Conclusion on Types of Computer Storage Devices:

To summarize what we have explained, you can divide the types of computer storage devices in two ways. Primary & Secondary, or Internal & External. Primary Storage is usually termed as Primary Memory of a Computer, and secondary storage is called as Secondary Storage Devices of a computer.

Examples of Primary Memory are RAM, ROM, and Cache. Examples of Secondary Memory are Hard Disk Drive, SSD, Pen Drive, CDs, DVDs, Floppy, etc. In short, the memory devices in which the CPU stores data are called Primary Memory Devices. And, the devices in which the users store their data is called Secondary Storage Devices.

If you have any more queries, comment below. Also, tell us which secondary storage do you have, HDD or SSD or Both?