Rebuild It With Parity — TechKnowSurge

About this interactive

RAID 5 writes data blocks across the disks and adds a parity block to each stripe. With three disks, each stripe has two data blocks and one parity block, and the parity moves to a different disk with each stripe. The parity is an XOR of the data, bit by bit. Two bits that are the same give 0; two bits that differ give 1. So 0 and 0 give 0, 1 and 1 give 0, and 0 and 1 give 1. If a disk fails, XOR what survives. Where a surviving data bit and the parity bit match, the lost bit was 0; where they differ, it was 1. Example: a data block of 1011 and parity of 0110 give a lost block of 1101. That is how the array rebuilds the failed disk onto a new one.

What you'll learn

Calculate a RAID 5 parity block as the XOR of the data blocks, and rebuild a failed disk's bits from the surviving disk and the parity

Aligned to

CompTIA Security+

3.4 Explain the importance of resilience and recovery in security architecture.

Key terms

RAID 5: A RAID configuration that stripes data and distributed parity across three or more drives, providing read performance gains and the ability to survive the failure of any single drive.
Parity: Calculated redundancy data stored across drives in certain RAID levels that allows the array to reconstruct lost data mathematically if a single drive fails.
Exclusive Or: Exclusive Or is a fundamental Boolean and bitwise operation used extensively in cryptographic algorithms and stream ciphers for combining key material with plaintext.
Striping: A RAID technique that splits data across multiple drives sequentially to improve read and write performance.

Topics

Interactive Calculation

About TechKnowSurge

TechKnowSurge builds IT and cybersecurity professionals through hands-on, concept-first training built around real understanding — not memorization. Free interactive tools, structured programs, and 25+ years of real-world experience, all in one place.

Explore free tools and programs →