SSC CGL Preparation – Day 5

Computer Basics: Backup Devices

🔰 What is a Backup?

A backup is a copy of important data that is stored separately to restore original information in case of data loss, corruption, or hardware failure.

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🧠 Why is Backup Important?

• To prevent data loss due to system crashes, viruses, or accidental deletion.
• For disaster recovery in organizations.
• To maintain business continuity.
• To secure personal and sensitive data.

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💽 Types of Backup Devices

1️⃣ Hard Disk Drives (HDD)

• Most common storage device for backups.
• Available in internal and external versions.
• Large storage capacity (up to several TB).
• Mechanical device, slower than SSDs.

Example: Seagate 1TB External HDD.

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2️⃣ Solid State Drives (SSD)

• Faster than HDDs; no moving parts.
• More durable and efficient.
• Suitable for frequent backups and quick recovery.
• More expensive per GB than HDDs.

Example: Samsung EVO 500GB SSD.

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3️⃣ Optical Discs (CDs/DVDs/Blu-ray)

• Used for archival storage.
• Low cost, but limited storage (700MB for CD, 4.7GB for DVD).
• Becoming obsolete with modern alternatives.

Usage: Often used for storing drivers, music, or media backups.

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4️⃣ USB Flash Drives (Pen Drives)

• Portable and easy to use.
• Suitable for quick transfers and small backups.
• Storage capacity: typically 4GB to 1TB.
• Prone to loss and physical damage.

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5️⃣ Memory Cards (SD Cards, MicroSD)

• Common in smartphones, cameras, and tablets.
• Used for temporary storage and backups.
• Not preferred for critical or long-term data.

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6️⃣ Network Attached Storage (NAS)

• A storage device connected to a network.
• Accessible by multiple users.
• Supports automated and scheduled backups.
• Used by businesses and home offices.

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7️⃣ Cloud Storage

• Data is stored on remote servers via the internet.
• Accessible from anywhere, anytime.
• Examples: Google Drive, OneDrive, Dropbox, iCloud.
• Secure, scalable, and automatic.
• Requires internet connection.

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📁 Backup Methods

Method	Description
Full Backup	A complete copy of all data every time.
Incremental Backup	Only backs up data changed since the last backup.
Differential Backup	Backs up data changed since the last full backup.
Mirror Backup	Creates an exact copy of the source files.

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🔒 Best Practices for Backup

• Follow the 3-2-1 Rule:
  ➤ Keep 3 copies of data
  ➤ On 2 different types of storage
  ➤ 1 copy offsite (e.g., cloud or external drive)
• Automate backups whenever possible.
• Perform regular checks to ensure backup integrity.
• Encrypt sensitive data for security.

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🧾 Summary

Backup devices are essential tools for data safety and recovery. They range from physical media (HDDs, SSDs, USB drives) to virtual/cloud-based storage. Each has its pros and cons, and the right mix ensures reliable protection against data loss.