Coverage Dashboard

Auto-generated tracking of content coverage across all subjects. Last updated: 2026-08-16 (validation re-run, meta sync)

Summary

Overall Metrics

• Total markdown files: 2,117 (2,116 content pages plus SUMMARY)
• Total Mermaid diagrams: 4,883 (across 1,319 files)
• Total size: ~42 MB (src/)
• New content this session: ~249K words across 131 files
• Build status: ✅ All validation checks passing (SUMMARY, links, mermaid 100%, MathJax)

Dev Pull Audit — 2026-08-13

• Pulled origin/dev at 61ac3ce and checked the expanded Summary against the filesystem.
• Repaired 14 navigation/link defects: ten absent Summary pages and four stale relative links.
• Current integrity totals: 1,723 content pages, 4,405 Mermaid blocks, 7,405 internal graph links, 0 broken links, and complete Summary coverage.
• The repaired pages are intentionally concise and referenced; future loops can deepen them rather than accumulating empty placeholders.

Major New Sections (2026-08-13)

Git Section — 15 files

Complete Git reference: internals (objects, refs, packfiles), fundamentals, branching/merging, rebasing (interactive, –onto, autosquash), stashing, advanced ops (cherry-pick, revert, reset, reflog, bisect), remotes, tags, hooks, workflows (trunk-based, GitFlow, GitHub Flow), GitHub/PRs/code review, interview questions, cheat sheet.

Software Engineering — 10 files

SDLC models, Agile/Scrum (ceremonies, artifacts, velocity), requirements engineering (user stories, MoSCoW), software design (SOLID, DRY, KISS), code quality (clean code, tech debt, refactoring), documentation (ADRs, RFCs, runbooks), project management (estimation, risk), metrics (DORA, cyclomatic complexity), team dynamics, interview questions.

Programming Fundamentals — 10 files

Variables/types (value vs reference, stack vs heap), scope/lifetime, functions (closures, HOFs, generators, tail recursion), error handling (exceptions, Result/Option), type systems (static/dynamic, structural/nominal, generics), memory model (pointers, GC, smart pointers), I/O and serialization (Unicode, streams), modules/packages (semver, dependency management).

Security & Cryptography — 7 files

Authentication (OAuth 2.0, OIDC, JWT, MFA, SSO), authorization (RBAC, ABAC), web security (OWASP Top 10: XSS, SQLi, CSRF, SSRF, XXE), cryptography (AES/RSA/ECC, TLS handshake, password hashing with bcrypt/Argon2), secrets management.

Machine Coding — 10 files

Approach & strategy, design principles in practice, complete solutions: parking lot, elevator system, library management, splitwise, rate limiter (token bucket, sliding window), LRU cache (O(1)), task scheduler.

Data Engineering — 7 files

ETL/ELT, warehouses/lakes/lakehouses, Spark (RDDs, DataFrames), Kafka (consumer groups, exactly-once), Airflow (DAGs), Parquet/Avro/ORC (columnar vs row), data quality.

Search Engines — 5 files

Inverted indexes, TF-IDF/BM25, Elasticsearch architecture (shards, replicas, queries, aggregations), vector search (HNSW, ANN, embeddings, semantic search).

Aptitude — 11 files

Percentages, ratios/proportions, averages, profit/loss, time/work, speed/distance, probability/combinatorics, number systems, logical reasoning (syllogisms, blood relations, puzzles), data interpretation.

Placement Preparation — 6 files

Campus placement process, online assessment strategy, technical interview prep, HR interview (STAR method), group discussion.

Resume & Career — 7 files

Resume structure, ATS optimization, bullet writing (STAR format, quantified impact), projects, technical skills, common mistakes.

Behavioral Interviews — 5 files

STAR method deep dive, 30+ common questions with frameworks, company fit questions, scenario templates.

Communication — 4 files

Technical communication (explaining code/architecture), interview communication (clarifying questions), written communication.

Practical Programming Problems — 6 files

Parsers (JSON, CSV, URL, expression), CLI tools, file processing, concurrent problems (thread pool, worker pool), system utilities (circuit breaker, retry).

DBMS Interview Problems — 6 files

Classic SQL (Nth salary, duplicates, top N per group), window functions (running totals, gaps/islands), joins (anti-join, self-join), optimization scenarios, concurrency scenarios.

New Sections Added (2026-08-08 to 2026-08-09)

Batch 1 — Kernel, Networks, Backend, Lang, Interview (3 files)

• Kernel Modules (os/kernel/modules.md) — LKM lifecycle, insmod/modprobe, taint, eBPF vs LKM
• QPACK RFC 9204 (networks/http/qpack.md) — static 99 vs dynamic, encoder/decoder streams, RIC/Base, HPACK vs QPACK
• xDS Protocol (backend/containers/xds-protocol.md) — ADS, LDS/RDS/CDS/EDS/SDS, protobuf not YAML, SotW vs Delta, Istio mapping

Batch 2 — Go, Probabilistic, Tracing (3 files)

• Go Web Frameworks (languages/go/web-frameworks.md) — Gin 76k rps vs Echo 72k vs Fiber 89k raw, 3.2k with DB (<5% diff), 0-1 alloc Fiber vs 3-4 Gin, decision flowchart
• Probabilistic Data Structures (interview/system-design/probabilistic-data-structures.md) — Bloom 10 bits/elem @1% 1B=1.2GB vs HashSet 50GB, HLL 12KB fixed ~2% err, CMS overestimates, Python impl, Cassandra/Chrome/BigQuery use cases
• Kernel Tracing (os/kernel/tracing.md) — ftrace, kprobes 0.05us vs 0.5us, tracepoints, perf, bpftrace one-liners kprobe:do_sys_open

Batch 3 — Storage & Concurrency Core (3 files)

• WAL (storage/wal.md) — rule LSN/pageLSN, STEAL/NO-FORCE, ARIES Analysis/REDO/UNDO, CLR, group commit, fuzzy checkpoints
• LSM Compaction (storage/lsm-compaction.md) — leveled 10-30× WA vs tiered 2-4×, RA/SA trilemma, RocksDB knobs table, SAG, write stall
• RCU (concurrency/rcu.md) — publish-subscribe, grace period 2 barriers, quiescent states, rcu_dereference store-release, checklist

Batch 4 — Backend API & Storage Deep Dive (3 files) — Latest

• API Versioning (backend/api/versioning.md) — 6 strategies table URL Path dominant (safest default) vs query param vs header vs Accept vs date-based Stripe pinning vs no versioning evolution, caching Vary header, decision flowchart, Gin groups & Echo middleware & Deprecation/Sunset RFC 9745, 5 Qs, refs apiscout.dev & knowledgelib.io & oneuptime
• Rate Limiting Algorithms (backend/api/rate-limiting.md) — 5 algos fixed window 1 key approx 2× burst vs sliding log SORTED SET O(n) exact vs sliding counter 2 keys near-exact ~1% err best balance vs token bucket HASH 2 fields burst tolerant Stripe 100/sec burst 1000 vs leaky bucket queue steady, comparison table, distributed Redis Lua atomic token bucket script, local+sync hybrid, gateway Envoy RateLimitService 429, decision tree flowchart, refs Redis official tutorial & AlgoMaster & Layrs.me
• SSTable Format (storage/sstable.md) — BlockBasedTable diagram Data Block 4KB compressed, Index Block last key+offset, Filter Block Bloom per block, Footer 48 bytes magic, read path flowchart Index→Bloom→Data, building flush sequenceDiagram, partitioned index/filter for 256MB SST 0.5/5MB on-demand, tuning table, 5 Qs, refs Adam Comer blog & LevelDB Explained & RocksDB wiki partitioned filters

Batch 9 — Federation, distributed locks, tiered storage (3 files) — 2026-08-12

• GraphQL Federation (backend/api/graphql-federation.md) — entities, composition, directives, query planning, schema governance, and failures.
• Distributed Locks and Fencing Tokens (distributed/fundamentals/distributed-locks.md) — leases, Redis/Redlock, ZooKeeper, etcd, fencing, and alternatives.
• Tiered Storage and Data Temperature (storage/tiered-storage.md) — hot, warm, cold, RocksDB, object lifecycle, cache/index design, and recovery.

Batch 8 — eBPF networking, Rust async, OpenTelemetry (3 files) — 2026-08-12

• eBPF Networking (networks/ebpf-networking.md) — XDP, TC, socket and cgroup hooks, maps, AF_XDP, Cilium, CO-RE, and debugging.
• Rust Async Runtime Choices (languages/rust/async-runtimes.md) — Tokio, smol, async-std, Glommio, Monoio, Embassy, cancellation, and blocking work.
• OpenTelemetry (backend/observability/opentelemetry.md) — signals, propagation, Collector pipelines, semantic conventions, sampling, and cost.

Batch 7 — NVMe-oF, CRDTs, and CDC/outbox (3 files) — 2026-08-12

• NVMe over Fabrics (storage/nvmeof.md) — NVMe/TCP and NVMe/RDMA transport trade-offs, discovery, queueing, multipathing, security, and Linux operations.
• Conflict-Free Replicated Data Types (distributed/fundamentals/crdts.md) — SEC, CvRDT/CmRDT/delta CRDTs, causality, deletes, local-first, and OT comparison.
• CDC and Transactional Outbox (backend/patterns/cdc-outbox.md) — atomic local events, Debezium, logical decoding, idempotency, ordering, WAL retention, cleanup, and polling alternatives.

Batch 6 — Safe Memory Reclamation (1 file) — 2026-08-12

• ABA Problem and Safe Memory Reclamation (concurrency/aba-problem.md) — CAS ABA interleaving, tagged/versioned pointers, hazard pointers, EBR, RCU, reference counting, memory ordering, implementation choices, and interview questions; references Linux kernel docs, WG21 C++ safe-reclamation papers/current draft, IBM, Boost, Folly, and Crossbeam.

Batch 5 — Concurrency Advanced & BlobDB (3 files) — Latest

• Work-Stealing Scheduler (concurrency/work-stealing.md) — LIFO owner head hot cache vs FIFO thief tail cold, Go GMP P local 256 + global lock + random steal, Java ForkJoinPool WorkQueue 4096, Rust Tokio per-worker 256 ring + injection queue half-move cooperative, fairness random victim + barrier, global queue vs work-stealing table, Qs, refs Wikipedia Cilk/Java ForkJoin/.NET/Tokio, dev.to pattern, rustz2h deep dive, Andrew Odendaal architecture
• Memory Model (concurrency/memory-model.md) — TSO vs weak ARM/RISC-V, store buffering litmus r1=0 r2=0 on x86 YES, DRF-SC happens-before, C++11 6 orders relaxed/acquire/release/acq_rel/seq_cst/consume deprecated, release synchronizes with acquire example n=23, modification order, SC-DRF, Java volatile total order vs VarHandle acq/rel, Go channel send happens-before recv + race detector, Rust Send/Sync Ordering, acq/rel vs seq_cst weakness store buffering allowed, fences, Qs, refs Grokipedia, Russ Cox PLMM, Modernes C++, Boehm SC proof
• BlobDB (storage/blobdb.md) — KV separation for large values, WiscKey insight, RocksDB Integrated BlobDB design flush if V>=min_blob_size → blob file + SST K+BlobIndex file_no/offset/size, GC age cutoff 0.25 oldest files relocation, options enable_blob_files/min_blob_size/blob_file_size/enable_blob_garbage_collection, leveled recommended, performance bulk load 2.3-4.7× faster WA 1.0-1.02 vs 1.6, overwrite 1.4-1.7 vs 6.1-6.8 75-78% lower, trade-offs RA extra I/O SA higher via garbage, WiscKey vs Badger vs RocksDB, Qs, refs RocksDB Wiki BlobDB + Integrated Blob Blog + Pebble Issue 112
• Meta fixes: 14 mermaid regressions after dev merge fixed (unquoted labels () {} |, Note over → NODE_FIX), 16 broken links fixed, bluetooth + congestion-control README added

Integration Batch — 2026-08-12

• Linux book (lb2): 444 source chapters integrated under src/linux/, plus a track overview and the original Linux Tools study component. Its navigation is adapted into this book’s Summary; repository workflows, generated output, and source deployment assets were excluded.
• DSA book (dsa_book_2): 193 source chapters and appendices integrated under src/dsa/, plus a track overview and references. The source’s anchor-named filesystem artifacts were excluded.
• Navigation: 1,544 Markdown files are present and 1,543 are linked from SUMMARY.md (the Summary file is the only excluded Markdown file).
• Link repair: 0 broken relative Markdown or image links.
• Mermaid repair: 4,387/4,387 pass the repository heuristic and Mermaid v11 parser validators.
• Branch safety: integration commits are on dev; main was not changed.
• mdBook build note: the full source tree builds to 1,585 files with search indexing disabled in the constrained sandbox. The normal search-enabled build was attempted twice and terminated by the environment with exit 137; book.toml was not changed to hide that limitation.

Priority Gaps Remaining (Updated 2026-08-12)

HIGH Priority — Covered:

1. CUDA Deep Dive — exists arch/parallelism/cuda.md ✅
2. Streaming system design — interview/system-design/real-world/streaming-pipeline.md ✅
3. Kubernetes operator pattern — cloud/kubernetes/operators.md ✅

MEDIUM Priority — Completed:

4. Go web frameworks ✅ languages/go/web-frameworks.md (2026-08-09)
5. Vue / Angular ✅ frameworks/vue-angular/README.md exists
6. Linux kernel modules ✅ os/kernel/modules.md (2026-08-08)
7. Service mesh internals xDS ✅ backend/containers/xds-protocol.md (2026-08-08)
8. QPACK ✅ networks/http/qpack.md
9. Kernel Tracing ✅ os/kernel/tracing.md
10. Probabilistic Data Structures ✅ interview/system-design/probabilistic-data-structures.md
11. WAL ✅ storage/wal.md
12. LSM Compaction ✅ storage/lsm-compaction.md
13. API Versioning ✅ backend/api/versioning.md
14. Rate Limiting ✅ backend/api/rate-limiting.md
15. SSTable ✅ storage/sstable.md
16. RCU ✅ concurrency/rcu.md
17. Work-Stealing ✅ concurrency/work-stealing.md
18. Memory Model ✅ concurrency/memory-model.md
19. BlobDB ✅ storage/blobdb.md

Remaining MEDIUM (Next Loop):

• Python GIL 3.13 free-threaded deep dive (languages/python/free-threaded.md)
• Java Loom Virtual Threads (languages/java/virtual-threads.md)
• Rust async runtimes comparison ✅ languages/rust/async-runtimes.md
• eBPF Networking Deep Dive ✅ networks/ebpf-networking.md
• Storage: Ceph CRUSH/RADOS deep dive (storage/ceph-crush.md) remains; NVMe-oF is complete in storage/nvmeof.md ✅
• Concurrency: ABA Problem & Hazard Pointers ✅ concurrency/aba-problem.md; transactional memory expansion remains
• Backend: GraphQL Federation ✅ backend/api/graphql-federation.md; CDC and Outbox are complete in backend/patterns/cdc-outbox.md ✅
• Distributed: CRDTs are complete in distributed/fundamentals/crdts.md ✅; Vector Clocks can still be expanded

LOW Priority:

• Quantum computing, blockchain (PoW/PoS, Merkle), edge computing (Cloudflare Workers, Fastly Compute@Edge)
• Observability Deep Dive: OpenTelemetry ✅ backend/observability/opentelemetry.md
• SSTable already done, BlobDB done — tiered storage is now covered; further work can focus on cost-model examples

Next Steps (Loop Continues)

• Expand Storage to 20+ pages: currently 18 → add Ceph CRUSH, NVMe-oF, tiered storage, BlobDB done, SSTable done, WAL done, compaction done — need Ceph RADOS, write amplification minimization, erasure coding deep dive already exists but could expand
• Expand Concurrency to 25+ pages: currently 18 → ABA, memory barriers, work-stealing, RCU, and memory-model coverage are present — need transactional memory expansion, work-stealing already done, maybe add lock-free queue, wait-free
• Expand Frameworks to 20+ pages: currently 9 → split Vue & Angular dedicated, add Svelte, Micronaut/Quarkus, Actix/Axum, Fiber/Chi done via Go web frameworks, need Rust Actix
• Expand Distributed to 50+ pages: currently 40 → CRDTs complete; add vector clocks deep dive and gossip tuning
• Keep meta updated each batch; current checks are 100% Mermaid and 0 broken links.
• Run and record the full mdBook build before declaring a future batch complete. The constrained build for this batch passed; the production search-enabled build is memory-limited here.
• Push incremental work to dev only for this task; do not modify main.