Storage MonitorDuring my internship at Two Sigma, I was tasked with building a platform for analyzing and monitoring internal storage systems. As a data-driven company, hundreds of petabytes of data are stored internally in various systems and data centers. To help keep track of the growing data storage (as well as things like misconfigured storage), I built a REST API that allowed you to query storage URIs and attributes like storage owners, total size, etc. This was backed by a "scraper" service that communicated with the various storage backends to collect the various metrics and settings for each storage location. The eventual goal for this platform is enabling better resource management by eliminating extra backups for unimportant data, cutting down on storage for abandoned data, and helping users optimize caching/pinning for their data to enable better performance.
Python, Flask, PostgreSQL, SQLite, ElasticSearch, lots of internal tools
Safe Promise-based Programming LanguageIn my research, I've been working in the Habanero Lab at Georgia Tech alongside Prof. Vivek Sarkar and Dr. Caleb Voss. We investigated a language designed to statically detect certain bugs in promise-based programs. For example, our language guarantees that a promise can never be fulfilled twice and that the programmer cannot ever forget to fulfill the promise. This has some far-reaching effects: it's able to detect many common bugs that result from incorrect use of promises, it ensures that promises are used consistently (i.e. there's never a race to fulfill a promise), and it allows for easy instrumentation to dynamically detect deadlocks. This is all accomplished using a linear type system, in which promises are split into read handles and write handles (think promise vs. future in C++). The language consists of a simple concurrent programming language built on top of Java and utilizes promises as it's core concurrency primitive. A simple compiler (complete with a type checker, small runtime, and Java code generation) has been implemented in OCaml. We also defined a formal operational semantics for the language and used it to prove the guarantees of the language. (I also got to play around with the Coq proof assistant, though found it too tedious for a few of the proofs). I'm glad to announce that this work will be published at ECOOP 2021 as "Linear Promises: Towards Safer Concurrent Programming"! Huge thanks to my co-authors/mentors Caleb and Vivek!
OCaml, Coq, LaTeX, Java, Type Theory
Rust Operating System for Raspberry PiWhen I took Operating Systems (CS3210), our semester long project involved building an operating system for the Raspberry Pi Model 3B+ in Rust. Our OS featured a "networked" bootloader over XModem+UART, support for the Pi's GPIO and timers, bin and bump memory allocators, a FAT32 filesystem, preemptive multitasking, a number of syscalls, and virtual memory. As our final project, my group focused on adding write support for the filesystem along with full-disk encryption. We also added support for mounting multiple filesystems, environment variables, file descriptors/locking files, command-line arguments and built a userspace shell using some POSIX-like syscalls. (Wow, too many class projects -- gotta find some time to work on some personal projects soon).
Rust, ARMv8/aarch64 assembly, Raspberry Pi
FPGA SRAM interfaceAs our final project for my Digital Design Lab (ECE2031), we were tasked with designing and implementing an SRAM interface for a simple computer on an Altera DE2 FPGA. Optimizing for performance, we chose to create a device with qword addressability, which enabled users to take advantage of spatial locality by performing multiple loads/stores simultaneously. We also clocked our interface asychronously from the CPU, which allowed us to communicate with the SRAM between CPU clock cycles. While not the most technically complex project on here, this project really helped me learn more about VHDL and FPGAs in general.
Altera FPGAs (DE2), VHDL, SRAM, Quartus, Logic Analyzers, Oscilloscopes
Optimizing Tiger CompilerIn my compilers class (CS4240), we completed a toy compiler for the Tiger programming language. Using OCaml, our team developed a complete middle-end and backend for the MIPS-32 architecture. Heavily utilizing dataflow analyses, the compiler featured deadcode elimination, copy propogation, and Chaitin-Briggs register allocation. Best of all, I got the chance to finally use Nanocaml in a real project!
OCaml, Nanocaml (Nanopass), OCamlGraph, MIPS-32, Dataflow Analysis
Pipelined Processor DatapathFor my Systems & Networks class (CS2200), we designed a number of datapaths for a RISC computer based on MIPS. We individually designed a simple datapath for this computer in a logic simulator called "CircuitSim", then built on top of it to add interrupts and support for external I/O devices. As an extra credit project, I created a 5-stage pipeline version of the computer, which supported data forwarding and flushing the pipeline in order to resolve various hazards.
CircuitSim (logic simulator), "LC-2200" ISA
WebAssembly N-API portIn 2019, I spent my summer at Google working with all the awesome folks on the Node.js team. As my internship project, I was tasked with rethinking how Node.js programs can compile with native libraries (compiled to WebAssembly). After prototyping a tool for generating glue code for bindings in C and JS, I decided on an approach based around the Node API (N-API). N-API's ubiquitous use for native libraries meant it was a great choice for porting existing libraries to WebAssembly and, more importantly, it was designed to be extremely portable. Taking advantage of this portability, I set out creating a port of the API to WebAssembly bindings. To do so, I created a fork of V8 that supported providing vendor "built-ins" to WebAssembly code. I then used C++ templates to generate type-safe wrappers for all N-API functions and finally modified the Node module loader to support these special WebAssembly "native modules."
GBA 8-ball GameFor my Computer Organization class (CS2110), we were tasked with creating a small GameBoy Advance game at the end of the year. I chose to create an 8-ball pool game in ~a week using C. Collisions are calculated using a tiny physics engine I wrote that utilizes fixed-point math. Drawing is done mainly using sprites (for the balls) and affine sprites (for the cue, i.e. sprites with a transformation matrix).
C, GBA BIOS
ReveryRevery is a desktop GUI framework largely inspired by Flutter and Electron. The framework is written in ReasonML and compiles to native code, using a React-like API to make development simple. The components are implemented in OpenGL/WebGL to allow for a seamless experience across all platforms in the same way that Electron and Flutter provide. The project was originally created by Bryan Phelps, and I'm one of many collaborators for the project.
QuartzQuartz is a research project that aims to create a strongly-typed language for the world of message-passing, concurrent code. Largely inspired by the Alpaca project, which aims to give Erlang static typing, Quartz attempts to apply multiparty session type theory to Erlang-style code. In order to do so, the compiler implements a novel type inference/type checking algorithm based on Pierre-Malo Deniélou's and Nobuko Yoshida's research into global session type synthesis. The language itself is based loosely on Ruby and Elixir and compiles to Erlang code, but is designed around a new paradigm for actor programming using first-class session objects.
OCaml, Erlang/BEAM VM, Multiparty Session Types
RolltraxRolltrax started in late 2017 when my Work-Based Learning teacher, Brian Patterson, brought up the many challenges of having student interns to me and my friend Zach Baylin. Together, the three of began implementing a website for managing off-campus students' attendance. This quickly evolved into a full-fledged app, complete with user-customizable dashboards to view metrics about student performance, a route manager for teachers travelling between job locations, and tools for employers to evaluate students' performance. The latest revision of the web app is written in Crystal (using Kemal) and ReasonML (using ReasonReact), while the mobile app is written in Flutter.
Crystal, Kemal, ReasonML, React, Python, Qt, Ruby, Sinatra, Flutter, Dart, Postgres, GCP
NanocamlHaving been interested in compiler design for a while, I was intrigued when the idea of nanopass architecture was first brought up to me. This style of writing compilers utilizes a large number of passes, each of which performs only a tiny transformation on the input program. After watching a talk and using the Racket nanopass library for a school project, I became inspired to design a similar system for OCaml. Using a PPX preprocessor, my friend Milo Turner and I whipped up a quick prototype of what such a library could look like. Though not yet battle-tested, this library provides a number of powerful abstractions for writing compilers quickly and easily.
OCaml, Nanopass Compilers, PPX preprocessors
KesefOver the summer of 2018, I became very interested in learning about finance. As part of this, I spent quite some time learning about financial statements such as those found in the 10-k/q SEC filings. To make browsing these forms easier, I used Perl6 to create a program called Kesef, which used a web scraper and RSS feeds to create a database of company filings. I also added some more features, such as rudimentary parsing of the XBRL documents to create tables of financial data and sourcing trading information from the IEX Trading API.
Perl6, XML (XPath, XQuery, and XSLT), IEX API
BibliotechDuring my senior year of high school, I competed in FBLA's Mobile Application Development competition with Zach Baylin and Eric Miller. For the competition, we were tasked with creating an app for browsing and checking out library books. After a failed first attempt using the Jasonette framework, we switched to Flutter (and fell in love with it!). The backend of the app was implemented in Ruby using Sinatra and PostgreSQL.
Flutter, Dart, Ruby, Sinatra, PostgreSQL