Chapter 1 · Computer Networks

1.15Data Backup and Recovery

Why we keep copies of important data, the three types of backup, and four ways to get lost data back.

Written and checked by Muhammad Raheel(opens in a new tab)

Full Stack Developer · AI Engineer · Reviewed 21 Oct 2026 · 2 min read

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Imagine your laptop stops working the night before you submit a project. If you have a copy somewhere else, you lose nothing. That copy is a backup, and getting your work back from it is recovery.

A backup protects data from loss or damage. Data can be lost because of viruses or because hardware fails, for example when a hard disk breaks. With a backup, the data can be restored easily.

The book calls backup and recovery very important for safety. Its advice is clear: every user should back up data regularly.

Four steps: data backup, data lost due to viruses or hardware failure, recovery, data restored, with the backup types and recovery methods below

Types of Data Backup

The book describes three types:

Type	What it saves (book wording)
Full backup	all data at once
Incremental backup	only changed data
Differential backup	changes since last full backup

A full backup copies everything, so it takes the most time and space. The other two copy only what changed, so they are faster.

Where do backups live? The book names hard drives and cloud storage. Cloud storage keeps your copy on servers on the internet, away from your own device.

Data Recovery Methods

The book lists four methods:

Backup files are used for recovery: you copy the saved data back.
Recovery software helps get deleted files back.
System restore can recover system data, such as the computer's settings.
Professionals can recover data from damaged devices, such as a broken hard disk.

All these methods help reduce data loss. Backup files are the easiest, which is why making backups regularly matters so much.

Practice this topic

All MCQs of this chapter with answers

Short questions

1.What is data backup?2 marks
Answer
From the book: "Data backup means making a copy of important data. It helps protect data from loss or damage." "Backup allows data to be restored easily."
2.What is data recovery?2 marks
Answer
From the book: "Recovery is the process of getting data back." "Data recovery is used to restore lost data. Backup files are used for recovery."
3.Why are backup and recovery important?3 marks
Answer
From the book: "Data can be lost due to viruses or hardware failure." Backup "helps protect data from loss or damage" and "allows data to be restored easily." "Backup and recovery are very important for safety. Every user should back up data regularly."
4.Name the types of data backup.3 marks
Answer
From the book: "Full backup saves all data at once. Incremental backup saves only changed data. Differential backup saves changes since last full backup." "Backups can be stored on hard drives. Cloud storage is also used for backup."
5.Differentiate between incremental backup and differential backup.2 marks
Answer
From the book: "Incremental backup saves only changed data." "Differential backup saves changes since last full backup."
6.Write any three data recovery methods.3 marks
Answer
From the book: "Backup files are used for recovery. Recovery software helps get deleted files. System restore can recover system data. Professionals can recover data from damaged devices." Any three of these four. "Recovery methods help reduce data loss."

Long questions

1.What is data backup and recovery? Describe the types of data backup and the data recovery methods.8 marks
Answer
The book gives 1.15 only three short paragraphs, so this one long question covers the whole topic. Use the book's text:
1. Backup and recovery (verbatim): "Data backup means making a copy of important data. It helps protect data from loss or damage. Data can be lost due to viruses or hardware failure. Backup allows data to be restored easily. Recovery is the process of getting data back. Backup and recovery are very important for safety. Every user should back up data regularly."
2. Types of Data Backup (verbatim):
  
  "Full backup saves all data at once."
  
  "Incremental backup saves only changed data."
  
  "Differential backup saves changes since last full backup."
  
  Storage: "Backups can be stored on hard drives. Cloud storage is also used for backup."
3. Data Recovery Methods (verbatim): "Data recovery is used to restore lost data."
  
  "Backup files are used for recovery."
  
  "Recovery software helps get deleted files."
  
  "System restore can recover system data."
  
  "Professionals can recover data from damaged devices."
  
  Close: "Recovery methods help reduce data loss."
Aim for 200-300 words.

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