The storage capacity of processor memory, also known as primary memory, is very low and volatile, in which the stored data is destroyed as soon as the computer is turned off. In such a situation, if we have to store a large amount of data or program permanently, then we need secondary memory.
Let’s understand in detail what is secondary memory? what are the types of secondary memory? And What are the features of secondary memory?
What is Secondary Memory
Definition -: Secondary memory is the secondary storage device of the computer which is used to store the program in the computer and the output obtained from the execution of the program permanently.
Secondary memory is a non-volatile memory in which all the data and information stored in the computer remains saved even after the computer is turned off.
It is not directly accessed by the CPU like primary memory. The data from the secondary memory is first loaded into RAM (Random Access Memory) or primary memory and then sent from the primary memory to the processor (CPU) to read and update the data.
Secondary memory is a permanent storage memory which is much slower and cheaper than primary memory.
Secondary memory is also known as external memory or auxiliary storage, inside which data can be stored in gigabytes and terabytes.
It is also called Backup Storage or Mass Storage Media.
Examples of Secondary Memory –:
- Magnetic Tape
- Magnetic Disk
- Floppy Disk
- Hard Disc
- Compact Disc
- Pen Drive
- Flash Drive
- Optical disk drives (CD or DVD)
Types of Secondary Memory
Secondary memory is of two types depending on whether it is part of CPU or not –
- Fixed Storage Device
- Removable Storage Device
#1. Fixed Storage Device
Fixed storage media is an internal storage media like a hard disk that is fixed inside the computer.
Fixed storage is an internal media device known as Fixed Disk Drives or Hard Drives.
Fixed storage devices are not really completely fixed, they can be removed for system repair, maintenance, and upgrade, etc.
But it cannot be opened without a toolkit and if it needs to be opened for upgrade or any other work then this work is done by an engineer.
Types of Fixed storage:
- Internal flash memory (rare)
- SSD (solid-state disk) units
- Hard disk drives (HDD)
#2. Removable Storage Device
Such storage devices that are outside the computer and which can be removed from the computer anytime, by connecting with the computer, are called Removable Secondary Storage devices.
Removable storage is an external media device known as removable disk drives or external drives.
Removable Storage Device is a storage device that can be removed from the computer system while the system is running.
Examples of removable devices include CDs, DVDs, and Blu-ray disk drives, as well as diskette and USB drives.
Removable storage devices make it easy for the user to transfer data from one computer system to another.
Types of Removable Storage:
- Optical discs (CDs, DVDs, Blu-ray discs)
- memory cards
- Floppy disks
- magnetic tapes
- Disk packs
- Paper storage (punched tapes, punched cards)
Let us now understand about some popular secondary storage devices.
Different Types of Secondary Storage devices
- Hard Disk
- Solid-state Drive
- Pen Drive
- Blu Ray Disc
- SD Card
- CD Drive
- DVD Drive
1. Hard Disk
It is a rigid magnetic disc that is used to store data and programs. It stores data permanently in the computer and is located within a drive unit.
Hard Disk is also known as Hard Drive.
It is a non-volatile storage device. consisting of one or more platters that are packed in an air-sealed casing.
A hard disk is made up of a series of circular discs, called platters, which are arranged around a spindle no more than about an inch.
Hard disks are made of a non-magnetic material such as aluminum alloy and coated with a 10-20 nm magnetic material.
The standard diameter of these discs is 14 inches.
Data is stored by magnetizing or demagnetizing the magnetic coating.
Data stored on a computer’s hard drive typically includes the operating system, installed software, and user files and programs, including pictures, music, videos, text documents, etc.
A magnetic reader (ARM) is used to read data and write data to disk. A normal modern HDD has a capacity of terabytes (TB).
Components of Hard Disk
The main components of a hard drive include a head actuator, read/write actuator arm, read/write head, platter, and spindle.
A circuit board, called a disk controller or interface board, is present on the back of the hard drive. It allows the hard drive to communicate with the computer.
2. Solid-state Drive
SSD (Solid State Drive) is also a non-volatile storage device like HDD which is used to store data and information in the computer. There are no moving parts inside an SSD (Solid State Drive) like there were in a hard disk.
Due to the absence of moving parts in SSD (Solid State Drive), data can be accessed easily, which also saves power and time.
Talking about SSD (Solid State Drive), it is a bit expensive than HDD, but as the cost of SSD has come down, it is being used in place of hard disk in desktop and laptop computers.
It is suitable for notebooks, laptops, which do not require a lot of storage.
3. Pen Drive
Pen drive is a portable secondary storage device also known as a USB flash drive, thumb drive, and jump drive.
The pen drive is connected to the computer through the USB port. It is used for data transfer between computers.
Pen drive does not have any type of movable part, it has a chip made of an integrated circuit which stores data. This chip is placed inside a plastic or aluminum casing.
The data storage capacity of pen drives generally ranges from 2 GB to 128 GB. Furthermore, it is a plug-and-play device as you do not need any separate drive, software, or hardware to use it.
4. Blu Ray Disc
Blu Ray Disc (BD) is an optical storage media used to store high-definition (HD) video and other multimedia files.
BD (Blu Ray Disc) uses a shorter wavelength laser as compared to CD/DVD. BDs can store up to 128GB of data.
5. SD Card
SD Card, also known as Secure Digital Card. It is a portable storage device that is mostly used in smartphones and digital cameras.
Whenever you want, you can remove it from your smartphone and by connecting it to the computer, you can also see the stored data inside it with the help of card reader.
SD card does not have any moving parts like hard disk. There are many chips inside it which work to store the data.
There are many SD cards available in the market which have different storage capacities such as standard SD cards, mini SD cards, and micro SD cards. |
6. CD Drive
CD (Compact Disk) is a portable secondary storage device. which is circular. It is made of polycarbonate plastic.
The CD concept was developed in 1982 by Philips and Sony together.
The first CD (Compact Disc) was made on 17 August 1982 in a Philips workshop in Germany.
Initially, it was used to store and play sound recordings, later it was used for various purposes such as storing documents, audio files, videos, and other data such as software programs on CDs.
7. DVD Drive
The full form of DVD is Digital Video Display. It is a type of optical media, used to store optical data.
Although its size is similar to CD, but its storage capacity is much more than the CD. Therefore, it is mostly used for storing and watching movies and distributing software programs.
DVD was developed in 1995 by Sony, Panasonic, Philips and Toshiba.
Features of Secondary Memory
Secondary Memory have following features
- Secondary memory is also known as a backup memory.
- It is a non-volatile memory.
- The data is permanently stored in the secondary memory.
- It is used to store data and programs in the computer.
- Computer can also run without secondary memory.
- Secondary memory is slower than primary memory.
- It is cheaper than primary memory.
- It consists of optical and magnetic memory for storing data.
- This is an external memory.
FAQ – Frequently Asked Questions
How Many Types of Secondary Memory?
Depending on whether it is part of the CPU or not, Secondary Memory is of two types -: 1) Fixed Storage Device, 2) Removable Storage Device
What Are The Examples of Secondary Memory Device
Examples of secondary memory devices are – Hard Disk, Solid-state Drive, Pen Drive, Blu Ray Disc, SD Card, CD Drive, DVD Drive
Read More -:
- What is Computer Memory
- What is Primary Memory
- What is Cache Memory
- What is Register Mmeory
- What is Random Access Mmeory
- What is Read Only Memory
- What is Magnetic Tape
- What is Magnetic Disk
- What is Floppy Disk
- What is Optical Disk
- What is CPU (Central Processing Unit)
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