What is Secondary Memory

What is Secondary Memory and its types

What is Secondary Memory in Computer? We will understand it better in the post. You must know that there are two types of computer memory, primary and secondary. Now since we keep 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 of volatile nature, which means that they store the data permanently. As soon as the computer is turned off, the data stored in these memory devices is completely erased. That is why Secondary Memory is used in the computer.

This storage device keeps your programs and data stored permanently in the computer. Only the user can delete the data stored in these memory. Hard disks and solid-state drives are the most common examples of these. Next we will learn about the examples of secondary memory and their uses. But first of all what is the secondary memory in the computer? Understand it

In this post you will read about the following topics:-

• what is secondary memory
• types of secondary memory
• Features of Secondary Memory
• Primary vs. Secondary Memory
• in short

What is Secondary Memory

Secondary memory is the permanent storage device of the computer. This is where large amounts of data and software programs are stored permanently. The storage capacity of a secondary memory is up to a maximum of 16TB (Terabytes), in contrast, the primary memory can only store data up to a maximum of 32 GB (Gigabytes).

So whatever files, applications, multimedia, videos, audios and photographs etc. we keep in the computer, all of them are stored in Secondary Storage. There is a reason behind calling them Secondary Memory, that is, the computer processor cannot directly access the data stored in them, for that the data is first loaded into Primary Memory (RAM). As a result, secondary memory is much slower than RAM.

Since the data stored in these remains safe even in the event of power loss or computer shutdown, that is why they are called non-volatile. Mainly in desktop computers, HDD and SSD are called “Secondary Memory“. Although Pen Drives, CDs and DVDs etc. also fall in this category. Which are used as backup memory. Their main feature is that their storage capacity is high and at the same time it is cheap.

Types of secondary memory

Secondary memory is mainly classified into four parts:

• Magnetic Tape
• Magnetic Disk
• optical disk
• Flash memory

1 Magnetic Tape

Magnetic tape is one of the oldest storage devices to store electronic data. However, its use in computers was discontinued a long time ago. It is a sequential access memory, in which the stored data can be accessed in sequence only. For example, the Audio Cassette used in the old times, in which if five recordings are saved and you want to listen to the fourth number. So you can’t play it directly.

For this, you have to play the first three recordings in sequence, then you will be able to reach number four. Often this was done by twisting the ribbon on the tap to fast-forward the first three recordings. The design of these tape drives used in computers is like a common cassette with a reel of plastic ribbon on both sides in which binary data was stored.

2 Magnetic Disk Drives

Magnetic disk is used as a main secondary memory in a computer. It consists of a circular plate made of metal, on which a layer of magnetic material is mounted. Information is stored on the surface of these disc plates. In addition to this metal plate called platter, a mechanical arm is also installed in the magnetic disk. Its job is to receive (read) and store (write) data from the surface of the platter.

Direct Access Method is used in these memory to get the data. Which means that the user can directly access any information stored in the 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 the computer. Because it is the only memory device present in the system that keeps the operating system, computer applications and your data files stored for a long time. Due to which it is also called Permanent Storage Device. The hard drive is located inside the computer case and is connected to the system board in the computer via a data cable (PATA, SATA, SCSI). Usually their storage capacity is very high.

Floppy Disk: This is a removable magnetic disc. Which was used as the main storage device in computers until the 1990s. However, after this, Optical Drives and Hard Disks gradually started replacing it. It is also called Floppy Diskette. It is made up of a flexible magnetic disk that is fitted into a square-shaped plastic case.

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

3 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, videos and software programs. These use a laser beam to record and retrieve digital data. Although it cannot store as much data as Hard Disk, but their storage capacity is much higher than Floppy Disk.

Some of the most commonly used optical discs are as follows-

Compact Disc (CD): This is a circular disc made of plastic that 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, that is, it can be inserted and removed in the system. A user can hold up to 700MB of data in a CD.

Digital Versatile Disc (DVD): It is also commonly called Digital Video Disc. It is similar to CD. However, large amounts of data can be stored in them. The storage capacity of these discs ranges 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 in this, many times more data can be stored than these two. A Blue-ray Disc can hold about 25 GB of data. In these, mainly high-definition videos or movies are stored. Since Blue Laser is used to read the data, due to which it is called Blu-ray.

4 Flash memory

This is a very popular secondary memory, which is mostly used to keep the backup of the data. It is different from other memory devices because the data is stored and deleted electrically in it. Usually this 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 used well-

Memory Card: This is a small chip, mainly used to hold 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 present in it can be easily accessed by putting the Pan Drive in the USB port of the desktop.

SSD (Solid-State Drive): It is the data storage device of this generation which is being used more and more in computers nowadays. Since many moving parts are used to store and receive data in HDDs, unlike SSDs, NAND flash memory is used which does not have any kind of moving parts. This is the reason why SSD is much faster storage than HDD. SSDs are also small in size, although in terms of price, they are much more expensive than HDDs.

Features of Secondary Memory

• It is non-volatile nature memory.
• In these data can be stored permanently.
• Secondary memory has the capacity to store many TB (Terabytes) of data.
• Their cost is much less than the primary memory.
• They are used as backup memory in computers.

Difference between primary and secondary storage

Primary Memory

• It is permanent and temporary memory.
• Primary memory is more expensive than secondary memory.
• The data stored in these memory is directly accessed by the CPU.
• It is also called Main Memory or System Memory.
• It is a fast memory although their storage capacity is less.
• Examples of this are – RAM, ROM, Cache Memory and Register.

Secondary Memory

• It is a permanent memory.
• Whereas Secondary Memory is cheaper than Primary Memory.
• In order to access the data stored in these memory, the CPU first loads the data into the primary memory.
• It is also called Secondary Storage Device and External Memory.
• While secondary memory is a slow memory but it can hold a large amount of data.
• Examples of this are – Hard Disk and Solid-State Drive etc.

In short

Let us finally what is Secondary Memory? Let’s understand it briefly. It is the storage device of the computer where you can keep your files, software and other types of data permanently. It is different from primary memory because it can store a large amount of data. So hopefully, by reading the post, you must have understood that what is the secondary memory in the computer? But if you have any question or suggestion related to this, then please tell through comment.

In the end, if the post is informative, then please do share it on social media, so that other people can reach this information through you.

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