Disaster recovery planning in SCADA systems - Time & Space Complexity
When planning disaster recovery in SCADA systems, it's important to understand how the time to restore operations grows as the system size increases.
We want to know how recovery steps scale when more devices or data points are involved.
Analyze the time complexity of the following recovery process code snippet.
// Pseudocode for restoring device states after failure
for each device in system_devices:
backup_data = retrieve_backup(device.id)
if backup_data is valid:
restore_device_state(device, backup_data)
else:
log_error(device.id, "Backup missing or corrupted")
This code restores each device's state from backup one by one after a system failure.
Look at what repeats in this recovery process.
- Primary operation: Looping through each device to restore its state.
- How many times: Once for every device in the system.
As the number of devices grows, the time to restore grows too.
| Input Size (n) | Approx. Operations |
|---|---|
| 10 | 10 restore steps |
| 100 | 100 restore steps |
| 1000 | 1000 restore steps |
Pattern observation: The time grows directly with the number of devices; doubling devices doubles the work.
Time Complexity: O(n)
This means the recovery time increases in a straight line as more devices need restoring.
[X] Wrong: "Recovery time stays the same no matter how many devices there are."
[OK] Correct: Each device needs its own restore step, so more devices mean more time.
Understanding how recovery time scales helps you design better disaster plans and shows you can think about system growth clearly.
"What if we could restore multiple devices at the same time? How would the time complexity change?"