Secondary Storage Devices

The memory unit of the computer has been compared to human memory. However, human beings cannot remember everything, so we write things down in a notebook. The notebook serves as a permanent copy of data or information. Similarly, in order to supplement its memory, the computer is equipped with a secondary memory using secondary storage devices. Instead of a notebook, the computer stores data in media like the Hard Disk(HD), Compact Disk(CD), Digital Versatile Disk (DVD), Blue-Ray Disk, and Flash drives. This secondary memory stores data and instructions permanently, and it's also referred to as external memory.

Secondary storage devices are used in most computer systems to enhance the limited storage capacity of the RAM(Random Acess Memory). Secondary storage (or external memory) differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input or output channels to access secondary storage. Secondary storage does not loose the data when the device is powered down – it is non-volatile.

Examples of Secondary Storage Media

Hard Disk Drive (HDD)

A Hard Disk Drive (HDD) is a primary storage device used in computers. It consists of spinning disks called platters, which store data using magnetic particles. A read/write head accesses and saves data on these platters. HDDs provide a large amount ofstorage space for files, documents, and software. They are commonly used to store the operating system and user data on personal computers.

Compact Disk (CD)

A Compact Disk (CD) is an optical storage medium used to store digital data. CD's are typically circular and flat, with a reflective surface. Data is encoded onto the CD in the form of pits and lands on the surface. CD's can store various types of data, including music, software, and documents. They are read by a laser in CD drives, making the data accessible to the computer.

Digital Versatile Disk (DVD)

A Digital Versatile Disk (DVD) is another type of optical storage medium. DVDs are similar to CD's but can store larger amounts of data due to their higher capacity. They are commonly used for movies, software installations, and data backups. DVD's come in different formats, including DVD-ROM (read-only), DVD-RW (rewritable), and more.

Blu-ray Disk (BD)

A Blu-ray Disk (BD) is an advanced optical storage medium that offers even greater storage capacity compared to DVDs. Blu-ray technology uses a blue-violet laser to read and write data, allowing for higher data density on the disk's surface. Blu-ray disks are often used for high-definition movies and large data storage needs.

USB Flash Drives

A USB Flash Drive, also known as a thumb drive or a pen drive, is a small portable storage device. It connects to a computer's USB port and provides a convenient way to store and transfer data. Flash drives use flash memory technology to store data, which is retained even when the device is not connected to power. They are widely used for transferring files, creating backups, and carrying data on the go.