Secondary storage devices are non-volatile memory devices used to store  data. It basically means that unlike primary storage devices it retains the data even after the power is turned off.

Types of secondary storage devices are:

1 hard disk drives: mechanical devices that use spinning disks coated with magnetic material to store data. Its capacity ranges from 100 GB to several TB.

2. Solid state drives: Flash based storage devices with no moving parts using NAND flash memory. Its speed is much faster than HDDs.

3. Optical disks: We all know about CDs compact disk, DVD digital versatile disk. These are used for media distribution, backups and archival storage.

4. USB flash drives: portable storage devices using flash memory and a USB device.

5. Cloud storage: online storage provided by cloud service providers.

6. Network attached storage and external hard drives like portable hard drives that are connected via USB or something.

Hello,

Secondary storage devices are used to store data permanently or semi-permanently. They are not directly accessible by the CPU and are used for long-term data storage. Unlike primary storage (such as RAM), secondary storage retains data even when the computer is turned off. Here are different types of secondary storage devices:

1. Hard Disk Drives (HDD)

• Description : HDDs use magnetic storage to store and retrieve digital data using one or more rigid rapidly rotating disks (platters) coated with magnetic material.
• Capacity : They typically offer large storage capacities, ranging from hundreds of gigabytes (GB) to several terabytes (TB).
• Speed : Generally slower than SSDs due to mechanical movement.
• Use : Ideal for large-scale data storage such as operating systems, applications, and personal files.

2. Solid-State Drives (SSD)

• Description : SSDs use flash memory to store data, providing faster data access and transfer speeds compared to HDDs as they have no moving parts.
• Capacity : Available in a wide range, commonly from 120 GB to several TB.
• Speed : Much faster read and write speeds than HDDs.
• Use : Used in high-performance systems, laptops, and for applications requiring quick data access.

3. Optical Discs (CD/DVD/Blu-ray)

• Description : Optical discs store data using laser technology. CDs typically hold up to 700 MB, DVDs up to 4.7 GB (single-layer), and Blu-ray discs up to 25 GB (single-layer).
• Capacity : Lower capacity compared to HDDs and SSDs.
• Speed : Varies; generally slower than HDDs and SSDs.
• Use : Commonly used for media distribution, backups, and data transfer.

4. USB Flash Drives

• Description : Small, portable storage devices that use flash memory and connect via USB ports.
• Capacity : Range from a few GB to 1 TB.
• Speed : Varies depending on USB standard (USB 2.0, 3.0, etc.).
• Use : Ideal for personal data transfer, backups, and portable storage.

5. Memory Cards (SD cards, microSD cards)

• Description : Small, portable flash memory devices commonly used in cameras, smartphones, and other portable devices.
• Capacity : Range from a few GB to 1 TB.
• Speed : Varies by class and type (e.g., SDHC, SDXC).
• Use : Storing photos, videos, and other data on portable devices.

6. External Hard Drives

• Description : External HDDs or SSDs that connect to a computer via USB, eSATA, or Thunderbolt.
• Capacity : Similar to internal HDDs and SSDs, ranging from hundreds of GB to several TB.
• Speed : Depends on the type (HDD vs. SSD) and connection interface.
• Use : For additional storage, backups, and data portability

Hope it helps!