Types of External Memory (Secondary Memory)

The world has come ahead in terms of technology. Technology was never stable it keeps on developing and advancing as the world keeps evolving. The need for technology is very important, many people rely on technology to make their livelihood. There is a variety of elements that plays their part in the functioning of a device and memory is the key part that plays an important role in it. As memory is that part of the device which initiates the proper functioning, memory is required to carry the data and information which are needed to execute the functions. This article contains detailed information about the external memory of devices.

What is External Memory?

External memory is also referred to as Secondary memory; external memory is a removable memory that you remove as you please. CPU is not directly connected to the external memory. External memories come in various types that are used in different devices according to their support. External memory includes Memory cards, Compact discs, flash drives, and external hard drives. External memory can be used to transfer data from one another, you can copy the data you want to transfer from one device by connecting it and then paste the same into another. External devices are also portable.

Types of External Memory

Hard Disk Drive

HDD full-formed hard disk drive. HDD is also called hard disk, hard drive, and fixed disk. HDD memory is non-volatile. HDD keeps the data in it until the data in it is rewritten or removed. Hard drives have many beneficial features, HDD comes with large storage space, is portable, and can be carried anywhere. The hard disk drive was invented by IBM in the year of 1956. A hard disk is faster than an optical disk.

Magnetic Tape Device

The magnetic Tape Device was first introduced in the year of 1951, and it is still being used by many, magnetic tape device is in production and still used commercially and it’s still in development and improvement, research says that magnetic tape will be used on large scale in future. Data is written on the magnetic tape on the device through different means. The amount of data is depended upon the length and width of the tape. Magnetic tape is more reliable and provides a higher storage capacity than HDD.

Floppy Disk

A Floppy disk is also referred to as a floppy diskette. A Floppy disk is the media that read the data storage information. The disk is used to contain the electronic data. The Floppy disk was expensive in the start as it was one of the first portable storage devices created in 1967. First the floppy disk was only capable of storing 80kb of data, as the device was developed it was able to store the data of 800kb. As the floppy disk developed it was introduced in three sizes 8, 5.5, and 3.5 inches. Later, floppy disks were replaced by other better devices like a USB drive.


SSD is fully formed as Solid-State Drive. SSD is the type of external memory that is made using silicon microchips. SSD is same as the magnetic storage devices as the user can easily detach them from the device which is storing the data. SSD is a modern type of storage device which faster than any magnetic device as the data is stored in binary electrically on silicon strips also known as a cell.

Usb Flash Drive

USB full formed Universal Serial Bus. USB is a flash drive that is used for data storage. USB is rewritable and data is removable. USBs are usually small in size; they are compact and can be carried anywhere and are durable. USBs are small but have a very larger capacity and operate at a very fast rate. USBs are mostly used as storage for transferring portable devices. They cannot be used as software running and computer functioning. 

SD Card

SD CARD is fully formed as a Secure Digital card. SD cards are portable storage that is mostly used in devices like cameras, smartphones, etc. SD card comes in various options like full-size SD, mini-SD, and Micro SD, with different storage capacities. Same as USBs, SD cards are portable and easy to use. They are also mostly used for transferring files, and data and are not able to run programs and operating systems.


CD is fully formed as Compact Disk also referred to as an optical storage device. To use the compact disc, you require a CD reader which rotates the CD at a particular speed with a laser gliding over the CD surface and reads the data on it. CD can be read and are also able to write the data on it. CDs are mostly used to contain a small amount of data; the storage amount is limited to 700 MB. CDs are very cheap and affordable, but currently, not all devices have a CD reader in them.


DVD fully formed as Digital Versatile Disk. DVDs and CDs are identical to each other, and also work in the same way, but the DVDs come with a larger capacity than the CDs. DVDs have dual layering on them which increases their storage capacity. Most DVDs have a capacity of 4.7 GB to read and write on them. DVD also needs a DVD reader to function, but it is rare to find in today’s technology.


External Memory plays an important part in the devices, these types of memory are portable and easy to carry anywhere. External memory comes in various types and is used according to the need of the user. External memory is usually sturdier than any other memory not if the damage is because of physical impact. External memory is easy to use and is more reliable.

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