| Metric | Description | |---------------------------------|-----------------------------------------------------------------------------------------------| | **Uptime** | Total time a system is accessible, typically measured in hours and expressed as a percentage (e.g., 99.5% uptime). | | **Downtime** | Total time a system is not accessible, measured similarly to uptime. | | **Availability** | Calculated as: | | **MTTF (Mean Time to Failure)** | Average time between system failures. Electronics have high MTTF (25+ years); physical components have lower MTTF (≤5 years). | | **MTTR (Mean Time to Repair)** | Average time to repair a system, aiming for quick recovery. | | **MTBF (Mean Time Between Failures)** | Predicted time between system failures during operation. |
| **RTO (Recovery Time Objective)** | Time required to restore a system after an outage, crucial for business continuity planning. |
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# Discussion: Real-World Breaches `Choose one`, and let’s discuss what could have been done differently. Do you think stronger cybersecurity principles could have prevented the attack? Goal: Use real-world case studies to encourage students to think about cybersecurity in practice and what actions could have mitigated the impact of those breaches.