In RAM testing, which fault types does the checkerboard pattern help detect?

Introduction / Context:
The checkerboard test is a classic RAM diagnostic where alternating 0 and 1 values are written across memory cells, then inverted and verified. It is especially effective for catching coupling and adjacency-related defects. Recognizing what it detects helps in selecting appropriate test suites for memory validation.

Given Data / Assumptions:

• Pattern 1010… and its inverse 0101… are written alternately.
• Cells that neighbor each other experience opposite states.
• Verification reads check for corruption after writes and inversions.

Concept / Approach:
By placing opposite logic values in adjacent cells, the checkerboard stresses leakage paths, shorts, and capacitive coupling. Inverting the pattern and rechecking validates that each cell can reliably store both states and is not influenced by neighbors beyond acceptable limits.

Step-by-Step Solution:
Write initial checkerboard: 1010… pattern to the entire region.Read back to confirm integrity; note any adjacent corruption.Write inverse pattern: 0101… across the same addresses.Read back again to confirm that each cell can hold the opposite state.

Verification / Alternative check:
Industry memory test suites (e.g., March algorithms) include checkerboard-like phases for adjacent-cell stress to catch interference and shorts efficiently.

Why Other Options Are Wrong:
Options A, B, and C individually describe specific fault classes; the checkerboard can address all of them collectively.Option E: Data bus faults need different tests like walking ones and zeros.

Common Pitfalls:
Assuming a single pass is sufficient. Both the pattern and its inverse must be tested to confirm bi-stability and neighbor independence.

Final Answer:
All of the above