B7.1.1.1.4 DESCRIBING STORAGE DEVICES

Storage devices are hardware components used to store digital data. They can hold information such as files, software, documents, media, and even operating systems. Storage devices are classified based on their functionality, size, speed, and storage capacity.

Optical Drives are devices used to read and write data on optical discs like CDs, DVDs, and Blu-ray discs. They use laser technology to access and store data on the disc's surface.

Types of Optical Drives

1. CD Drives

   • Designed to read and write data on Compact Discs (CDs).
   • Commonly used for audio files, documents, and small data storage.
   • Maximum capacity: ~700 MB.

2. DVD Drives

   • Compatible with Digital Versatile Discs (DVDs) and CDs.
   • DVDs have a larger capacity compared to CDs, making them suitable for movies and larger files.
   • Capacity: 4.7 GB (single-layer), up to 8.5 GB (dual-layer).

3. Blu-ray Drives

   • Designed for Blu-ray Discs, which have a much higher storage capacity than CDs or DVDs.
   • Commonly used for high-definition movies and large data files.
   • Capacity: 25 GB (single-layer), 50 GB (dual-layer), up to 100 GB or more for newer models.

All optical drives however can be classified under the following;

1. Read-Only Discs

   • Examples: CD-ROM, DVD-ROM, BD-ROM.
   • Data is preloaded and cannot be changed.
   • Used for media distribution (movies, software, etc.).

2. Recordable Discs

   • Examples: CD-R, DVD-R, BD-R.
   • Users can write data once, but it cannot be erased.
   • Ideal for backups or permanent storage.

3. Rewritable Discs

   • Examples: CD-RW, DVD-RW, BD-RE.
   • Data can be written, erased, and rewritten multiple times.
   • Suitable for temporary or frequently updated data.

Types of Magnetic Storage Devices

1. Types:

   • Hard Disk Drives (HDDs): Large capacity (GB to TB), used in computers and servers.
   • Floppy Disks: Small capacity (1.44 MB), outdated.
   • Magnetic Tape Drives: High capacity (TBs), used for backups and archives.
   • Zip Disks: Moderate capacity (100–750 MB), now obsolete.

Types of Hard Disk Drives (HDDs)

SATA (Serial ATA):

• Most common interface for consumer HDDs.
• Affordable, with decent speed (up to 600 MB/s).

SAS (Serial Attached SCSI):

• Used in enterprise systems for high-speed data transfer and reliability.
• Faster and more durable than SATA.

IDE (Integrated Drive Electronics):

• Older interface, now largely obsolete.

Solid State Drives (SSDs)

Solid State Drives (SSDs) are data storage devices that use flash memory to store information. Unlike traditional hard drives (HDDs), SSDs have no moving parts, making them faster, more reliable, and energy-efficient.

Types of SSDs

Based on Interface:

SATA SSDs:

• Use the SATA interface, similar to HDDs.
• Slower compared to NVMe but more affordable.
• Speeds up to 600 MB/s.

NVMe (Non-Volatile Memory Express):

• Connects via PCIe interface, much faster than SATA.
• Speeds can exceed 3,000 MB/s, making it ideal for high-performance tasks

The picture below shows the internal parts of a hard disk drive.