Error Detection — Parity, Checksums & Check Digits
Learn how computers detect and correct errors in data transmission using parity bits, checksums, check digits, and majority voting.
📚 Learning Steps
💡 Study Tips
- • Read through at your own pace
- • Try the interactive simulators hands-on
- • Study the pseudocode — it appears in exams
- • Quiz yourself before moving on
Step 1: Why Do Errors Occur?
📖 TheoryWhen data is transmitted between devices (over a network, between components, or stored on disk), bits can be corrupted. A 0 might flip to a 1, or vice versa.
Causes include:
•Electrical interference (EMI) on cables
•Signal degradation over long distances
•Hardware faults in memory or storage
•Cosmic rays (yes, really — they can flip bits in RAM)
Error detection methods add extra information to the data so the receiver can check whether the data arrived intact.
🎯 Key Points
- •Bit errors occur during transmission and storage
- •Electrical interference, hardware faults, and signal degradation are common causes
- •Error detection adds redundant data to catch corrupted bits
- •Error correction goes further — it can FIX errors without retransmission
- •The trade-off: more redundancy = better detection but more overhead
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