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WebAssembly · 27 Environment and Adoption Criteria
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Stage: Correctness and Bottleneck Evaluation · External example · preview instructions · Storage ID: webassembly-step-27
Goals and learning outcomes
- Learning outcome: explain the role of Reproducibility. Input cases: small·medium·large arrays.
- Deliverable: correctness·total cost·maintenance judgments for each condition. Explain the rationale for handling Adoption criteria, linking it to the code.
Prerequisites
Prepare the experiment results for Correctness first and Error tolerance from Unit 26, “Boundary-value Correctness”.
Key concepts and explanations
Reproducibility
Runtime·device·input size change the results. Attach environment information to measured values.
Adoption criteria
Consider build·deployment·recovery costs as well as speed. Small inputs may show no benefit.
Practice setup
First check the execution scope guidance on the example screen. The following describes the environment needed to extend the assignment in a separate project. The iframe preview is an experiment with WebAssembly.Memory and JS reference computations; do not present it as execution of an actual Wasm module. Practice with actual modules in a separate Node 22+ environment or a controlled local web project. Use kernel.wat·kernel.wasm·benchmark.mjs in the existing src/labs/webassembly-02·03 folders, and rebuild with the official wat2wasm tool when modifying WAT. Preserve CSP·isolation, and record measurements yourself.
The linked example is a starting point. It does not implement every task below. Complete work beyond its supported scope in a separate project.
Practice tasks
- In day-27.mjs in a separate practice project, collect raw result JSON and environment information into a table of reasons for the choice. Refer to the existing Unit 1·14·28 examples only as starting points.
- Input conditions: small·medium·large arrays. Baseline: small. Run under the baseline conditions, then record observations and errors in notes/day-27.md.
- Variable: input size; changed value: large. Run again through the same input path. Deliverable to save: correctness·total cost·maintenance judgments for each condition. Hypothesis to check: Conditions with and without benefits are distinguished. Compare it with the actual results, and record whether they agree and why they differ.
Variables to observe
| Variable | Baseline | Change | Expected change / hypothesis |
|---|---|---|---|
| input size | small | large | Conditions with and without benefits are distinguished. |
Predictions in this table are not measured results. Change one condition at a time and record why the actual result differs.
Completion criteria
- Required deliverable: correctness·total cost·maintenance judgments for each condition. Results are available for both the baseline and changed conditions, allowing comparison of 2 conditions; input values and the execution environment are recorded together.
- The explanation of differences between the two conditions connects both concepts: Reproducibility and Adoption criteria. For unexpected items, at least 1 cause or reason they remain unresolved is recorded.
Self-check
- Which processing stage does Reproducibility affect in this exercise? Input cases: small·medium·large arrays.
- Variable: input size. Hypothesis to check: Conditions with and without benefits are distinguished. Did the actual results agree with the hypothesis? Explain the evidence in terms of Adoption criteria.
Official references
Linked example and execution scope
Example source · Runtime environments and limits
Standalone WAT + Node assertions; iframe CSP blocks Wasm compilation.
Source code and records are not overwritten automatically. Resetting an existing example also preserves your notes.
Next learning
Previous: Boundary-value Correctness · Next: Evaluating Actual Bottlenecks