What Is Secondary Memory and its types

What is Secondary Memory in Computer? We will understand it well in the post. You must be aware that there are two types of computer memory, primary and secondary. Now since we save our files, software, photographs and other types of data in the computer for a long time.

So this work cannot be done by Primary Memory because it is volatile in nature, which means that they store the data permanently. As soon as the computer is closed, the data stored in these Memory Device is completely erased. That is why Secondary Memory is used in computers.

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This Storage Device stores your programs and data permanently (Permanently) in the computer. Only the user can delete the data stored in these memory. The most common examples are Hard Disk and Solid-State Drive. In the next post, we will learn about the examples and uses of Secondary Memory. But what is secondary memory in a computer first?

What is Secondary Memory 

Secondary memory is the computer’s Permanent Storage Device. This is where large amounts of data and software programs are permanently stored. A Secondary Memory has a storage capacity of up to 16TB (Terabytes), in contrast Primary Memory can only store data up to 32 GB (Gigabytes).

So whatever files, applications, multimedia, video, audio and photographs etc. we keep in the computer, all of them are stored in these Secondary Storage. One reason behind calling them Secondary Memory is that the data stored in them cannot be accessed directly by the Computer Processor, for that the first data is loaded into Primary Memory (RAM). As a result, Secondary Memory is much slower than RAM.

Since the data stored in them is safe even in the event of loss of power or shutdown of the computer, they are called Non-Volatile. HDD and SSD are called “Secondary Memory” mainly in desktop computers. However, Pen Drives, CDs and DVDs etc. also fall in this category. Which are used as Backup Memory. Their main feature is that they have high storage capacity and are also inexpensive.

Secondary Memory is mainly classified into four parts:

  1. Magnetic Tape
  2. Magnetic Disk
  3. Optical Disk
  4. Flash Memory

Magnetic Tape

Magnetic Tape is one of the oldest storage devices to store electronic data. However, its use in computers stopped long ago. It is a sequential access memory in which the store data can be accessed in sequence. For example, an old-time audio cassette in which if five Recording is saved and you want to listen to the fourth number. So you cannot play it directly.

For this, you have to play the first three recordings in order, then you will be able to reach the fourth number. Often the taped ribbon was rotated to do this so that the first three recordings could be fast forwarded. The design of these Tape Drive used in computers is like a common cassette with plastic ribbon reels on either side of which the binary data was stored.

Magnetic Disk Drive

Magnetic Disk is used as a main Secondary Memory in computers. It consists of a circular plate made of metal, with a layer of magnetic material. Information is stored on the surface of these disc plates. In addition to this metal plate called Platter, the Magnetic Disk also has a Mechanical Arm. Its job is to obtain (read) and store (write) data from the surface of the platter.

Direct Access Method is used in these memory to retrieve data. Which means that the user can directly access any information stored in these Secondary Memory. There are many examples of Magnetic Disk but those which are mainly used in computers for Secondary Memory are as follows-

  • Hard Disk Drive: It is called the main data storage device of a computer. Because it is the only memory device in the system that stores the operating system, computer application and your data files for a long time. Because of which it is also called Permanent Storage Device. The Hard Drive is present inside the computer case and is connected to the system board in the computer through a data cable (PATA, SATA, SCSI). Their storage capacity is usually very high.
  • Floppy Disk: This is a removable magnetic disc. Which were used as the main storage device in computers until the 1990s. However, after this Optical Drives and Hard Disk slowly started replacing it. It is also called Floppy Diskette. It is made of a flexible Magnetic Disk fitted in a square shaped plastic case.

If you want to read / write information from Floppy Disk, then a Floppy Disk Drive (FDD) must be installed in your computer system. This is the reason why their use to store information in modern computers has stopped completely. There is another reason, however, that Floppy Disk can store a very small amount of data. Only 1.44 MB of data can be stored in a typical 3.5 inch disk.

Optical Disc

Optical Disc is also a storage medium, which we use as additional Secondary Memory in computers. These discs are commonly used to store music, video, and software programs. They use Laser Beam to record and retrieve digital data. Although it cannot store as much data as Hard Disk, but it has much higher storage capacity than Floppy Disk.

Some of the most frequently used optical discs are:

  • Compact Disc (CD): It is a circular disc made of plastic, which stores data optically. That is, Light is used to store and retrieve information in it. CDs are used to store audio, video and applications. It is removable, meaning it can be inserted and removed into the system. A user can hold up to 700MB of data in a CD.
  • Digital Versatile Disc (DVD): Also commonly known as Digital Video Disc. It is similar to a CD. However a large amount of data can be stored in them. The storage capacity of these discs varies from 4.7 GB to 8.5 GB. Mainly used to store high-definition (HD) videos or movies.
  • Blue-ray Disc: This is also a type of optical disc which is similar in size to CD and DVD. But it can store many times more data than these two. A Blue-ray Disc can hold about 25 GB of data. These mainly store high-definition videos or movies. Since Blue Laser is used to read data, it is called Blu-ray.

Flash Memory

It is a very popular Secondary Memory, which is mostly used for backing up data. This is different from other memory devices because the data is stored and deleted electrically. Usually it is a type of EEPROM. Since it is a removable storage device, they are also used to transfer data from one computer to another. Nowadays their use as External Memory has increased a lot.

Some examples of Flash memory that are well used are-

  • Memory Card: It is a small chip used primarily for storing data in mobile phones, cameras, MP3 players and other portable devices.
  • Pen Drive: It is a Portable Storage Device, which is most commonly used to transfer audio, video and other data files from one computer to another. The data can be easily accessed by applying Pan Drive to the USB port of the desktop.
  • Solid-State Drive (SSD): This is the new-age Secondary Memory which is being used more and more in computers nowadays. As HDDs use many moving parts to store and receive data, unlike SSD, NAND Flash Memory is used in which there is no moving part of any kind. This is why SSD is much faster storage than HDD. SSDs are also small in size, although they are much more expensive than HDD in terms of price.

Secondary Memory

  1. It is a memory of non-volatile nature.
  2. In these, data can be stored permanently (Permanently).
  3. Secondary Memory has the ability to store many TB (Terabytes) data.
  4. Their price is much less than Primary Memory.
  5. They are used as Backup Memory in computers.

Come on, what is Secondary Memory? Let’s understand it briefly. This is the storage device of the computer where you can keep your files, software and other types of data permanently. This is different from primary memory because it can store large amounts of data. So hopefully, by reading the post, you will be able to understand what is called secondary memory in a computer? But if there is any question or suggestion related to it, please tell through comments.

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