Digital information systems
Digital information systems examines how data moves through a system and how it is stored, protected and shared. Questions often ask you to choose hardware, software or a network configuration and justify the choice.
Core rules and concepts
- All systems can be described as input → process → output, with storage supporting each stage.
- RAM is volatile working memory; ROM or flash keeps firmware; secondary storage keeps files when power is off.
- A LAN covers a small area and is usually owned by one organisation; a WAN spans distance. Client-server centralises control; peer-to-peer shares directly.
- Bandwidth is capacity; latency is delay. A backup is a separate copy that can be restored; synchronisation is not a backup.
- Security controls include strong authentication, encryption, permissions, patching and user education. Personal data should be collected only when necessary.
Worked example
A class has 150 photos at 4 MB each and 20 minutes of 1080p video at 12 Mbps. Photos: 150 × 4 = 600 MB. Video: 12 Mbps ÷ 8 = 1.5 MB/s; 1,200 s × 1.5 = 1,800 MB. Total ≈ 2,400 MB (about 2.4 GB). A 4 GB USB drive is enough locally, but a second copy in cloud storage protects against loss; check upload time and privacy before choosing.
Traps
- Mixing MB and Mb (8 bits = 1 byte).
- Calling a synced folder a backup when a deleted file deletes everywhere.
- Confusing RAM with storage.
- Ignoring upload speed when recommending cloud backup.
- Treating "the cloud" as automatically private or secure.