W9

Question 1

What is file compression?

Answer 1

Storing a file’s data in less space by minimizing redundancy in the content

Question 2

What is an archive?

Answer 2

A collection of folders and files stored in one file

• Files are usually compressed
• Files can be encrypted
• Cross platform exchange

Question 3

Why use file compression?

Answer 3

• Writing/sending data takes bandwidth and I/O time

- Encrypt off-site data for security

Question 4

How does file compression work?

Answer 4

• matching and replacement of duplicate strings with pointers
• replacing symbols with new, weighted symbols based on frequency of use

Question 5

Lossless:

Answer 5

contains all original data with redundancies removed

ex. data archives, PNG/TIFF images, FLAC/ALAC audio

Question 6

Lossy:

Answer 6

sacrifices quality for smaller file size by dropping fine-grained, subtle details from the original data

ex. GIF/JPG images, most audio, all video
- for end users only, not for modification/editing

Question 7

Examples of compression file formats
Data:
Music:
Images:
Video:

Answer 7

Data: ZIP, 7z, RAR, .docx, .pptx, .xlsx, StuffIt, .tar.gz
Music: MP3, AAC, MQA, WAV, ogg, FLAC
Images: GIF, JPEG, RAW, PNG, TIFF
Video: MPG, MP4, DIVX, XVID, MOV, AVI

Question 8

Drawbacks to compression:

Answer 8

Time: compression needs CPU and primary storage resources
Space: archived files must be uncompressed before use, extra space needed for both compression and decompression
Integrity: the Lossy sacrifice is reduced quality
Recoverability: data corruption can cause loss of entire archive

Question 9

Why do we need backups?

Answer 9

Accidental deletion
Hardware failure

Less frequent causes:
Ransomware infection
Catastrophe
SQL injection attacks
cloud provider's business failure or account closed on cloud system

Question 10

What is RAID?

Answer 10

Redundant Array of Independent Disks

Question 11

Three characteristics that define a backup:

Answer 11

copy
geographically separate location
platform independent

Question 12

Classic file backup types:

Answer 12

Full + Differential

Full + incremental

Question 13

What is the 3-2-1 Backup Checklist?

Answer 13

3 copies
- 1 active, 1 local backup, 1 remote backup

2 different formats/platforms (platform independence)
- External drive is platform independent when not plugged in

1 off-site backup (geographically separate location)
- Cloud storage different from your cloud IaaS, PaaS, SaaS provider

Question 14

Backups do not matter…

Answer 14

Only restore matters

Question 15

Characteristics of Full + Differential backups

Answer 15

Changes file since last full backup
Full backup is slow, differential backup is faster but gets slower
Restore from Full + Differential is fastest

Question 16

Characteristics of Full + Incremental backups

Answer 16

Changes file since last backup
Full backup is slow, incremental backups are much faster than Differential
Restore from Full + Incremental sets is slowest