because External hard disk drives and Digital Audio Tapes (DAT) are available with storage space above 100 GB. If you have, a huge amount of data or your data would grow rapidly in near future you will have to buy a new whole unit to accommodate your data. If your storage requirement is limited, you can use these magnetic storage units.

Optical Storage:
These are ubiquitous CDs and DVDs. As we can see in real life, CDs and DVDs can be used to hold a wide variety of data formats Music, movies, games, images, data etc. Not all CDs or DVDs are the same. Look for the following before buying an empty CD or DVD. A CD can hold up to 700 MB data or 80 minutes of audio. DVDs can hold more than 6 times that data.
R (CD-R) Recordable: It can be recorded upon only once. It is good for making music CDs, storing photos and storing permanent data.
RW (CD-RW) ReWritable: It can be recorded onto as many times as desired. Data can be overwritten and erased. It is good for transferring files and holding temporary data.
Therefore, if your data grows over a period it is a good option for you as once you have a CD drive or DVD drive, all you need to spend is for empty CDs and DVDs that are quite inexpensive. However, you can only transfer data to another computer having a CD or DVD drive. You have to be careful with your CDs and DVDs and keep them safe from scratches and fingerprints and you should never bend them.

Flash Memory (Solid-State Removable Storage):
Solid-state memory (or Flash memory) is a high-performance plug-and-play storage device that contains no moving parts. They are quite useful in digital cameras, video game consoles and digital audio players. You can use it in the form of USB Flash Drives to transfer or backup data. You can read, write or erase files on this device. Flash memory is small, light and fast. These are also called because USB pen drives in some cases. They can hold data for a longer time without any damage compared to magnetic or optical media. They are quite useful for transferring files between various devices having USB port including computers. These USB pen drives are available up to 128 GB capacity now. We can expect much larger storage space in near future. However, these flash memory units are quite expensive compared to other portable storage media.

To be able to use any of the above options for data backup, having a USB port helps a lot. USB connectivity supports high data transfer rates and makes the process of backup or files transfers quite easy. posse.