Oitash Ghosh

A linearizable distributed key-value store built on Raft consensus, an LSM storage engine, and a linearizability checker that verifies the whole thing under network partitions.

• From-scratch Raft covering leader election, log replication, current-term-only commitment and snapshot compaction, sustaining 1,100 ops/s across 3 nodes, with leader failover measured at 334–526 ms.
• Hand-written LSM storage engine: a CRC-framed write-ahead log with torn-tail recovery, skiplist memtable, bloom-filtered SSTables and levelled compaction. Point reads land at 1.17 µs, and the filters skip 99% of tables on absent keys.
• Correctness is proved rather than asserted. A self-written linearizability checker (Wing & Gong, with Lowe's memoisation) verified 3,150 operations across 15 leader changes under repeated partitions, with zero anomalies. The checker itself is tested against six classes of known violation.
• Raised throughput 25 → 1,100 ops/s by isolating each layer: group-commit durability, an append-only log, and a lock-free counter on the apply path that was serialising every operation behind a 4 ms fsync.

A price-time-priority limit order book built the way a trading venue's hot path actually is: flat arrays instead of node graphs, a pre-allocated pool instead of malloc, a bitmap instead of a tree walk.

• Sustains 25 ns per message (≈39M msg/s, single-threaded) at p99 125 ns, using flat price-level arrays, intrusive FIFOs and a lock-free feed handoff.
• Validated trade-for-trade against an independently written reference implementation over 12M+ randomised commands, with zero divergences.
• Clean under AddressSanitizer, UndefinedBehaviorSanitizer and ThreadSanitizer. The benchmark probes the clock's own cost and resolution first, so a 25 ns operation is never measured through a 14 ns observer effect.

A full-stack hours-of-service planner that turns four trip inputs into a compliant route and auto-generated FMCSA log sheets.

• Renders a 24-hour duty grid per day in SVG, auto-generating the FMCSA log sheets drivers are legally required to keep.
• Dependency-free rules engine encoding six federal driving and rest limits, backed by 20 unit tests and a self-validation pass that flags violations.
• Replaced rate-limited reverse-geocoding calls with an offline 30,000-city index; Nominatim, OSRM and Leaflet give a zero-API-key map stack.

A role-based EdTech platform on the MERN stack, with course authoring, progress tracking, quizzes and payments.

• Three distinct dashboards for student, instructor and admin, with Redux holding global state across role-specific views and permissions.
• 50 REST endpoints over 12 data models covering courses, sections, quizzes, progress tracking and reviews.
• Razorpay payments and Cloudinary media behind JWT authentication, with tiered rate limiting on auth, email and global traffic.