Senior / Principal Engineering Portfolio

Product software, on-device ML, and systems engineering.

I build end-to-end software systems that span user-facing product architecture and hard runtime/platform work. This page is intentionally selective and meant to show depth relevant to senior/principal mobile, platform, and hardware/software-oriented engineering roles.

Apple Platforms

iOS and watchOS product architecture with polished multi-surface execution.

Applied ML

On-device prediction, personalization, and ML productization inside real user workflows.

Shared Runtime

Widgets, Live Activity, and watch surfaces driven from one normalized state layer.

Systems Depth

Kernel, runtime, memory, networking, executable loading, and desktop tooling.

Projects

Selected Projects

A small set of projects chosen to show product judgment, applied ML, and deep systems engineering across mobile and platform work.

Private iOS/watchOS product

On-device glucose forecasting and therapy decision platform

Swift, SwiftUI, Core ML, WidgetKit, ActivityKit, watchOS, SwiftData

A private iPhone and Apple Watch product built to turn live therapy context into forward-looking, reviewable decisions around meals, corrections, and exercise.

  • Built an on-device prediction experience that makes live therapy data useful before action, not just after the fact.
  • Designed meal and activity what-if flows, insight surfaces, and bounded personalization so the product becomes more useful as history accumulates.
  • Shipped a shared state layer reused across the iPhone app, widgets, Live Activity, and Apple Watch instead of rebuilding logic per surface.
  • Combined product design, ML integration, persistence, and cross-device runtime architecture into one coherent system.

From-scratch systems platform

Custom x86-64 operating system and native AI runtime

C, x86-64 assembly, scheduler, virtual memory, executable loading, local inference

A long-running systems project built from the metal up: boot flow, kernel, memory management, executable loading, native desktop surfaces, and local inference running inside an OS I wrote from scratch.

  • Spans the full stack from early boot and kernel bring-up through scheduler, VFS, section mapping, and user-mode runtime.
  • Implements the kind of systems work usually split across multiple teams: paging, file-backed memory, executable loading, process plumbing, and native debugging.
  • Brings local LLM inference directly into the platform with GGUF-based runtime components and agent-style workflows.
  • Pairs low-level infrastructure with visible product surfaces including a desktop shell, Finder-style tools, and Task Manager-style diagnostics.

Platform engineering

Networking, desktop UI, and native platform tooling

Drivers, IPv4, ICMP, UDP, TCP, TLS, window manager, native apps

Supporting platform work that pushed the operating system beyond a kernel demo and into something that behaves like a usable software platform.

  • Built driver-backed IPv4 networking with ICMP, UDP, and TCP support, plus TLS client tooling for secure outbound requests.
  • Implemented windowing, desktop interaction patterns, and first-party native tools that make the platform feel usable rather than academic.
  • Used these layers as a proving ground for debugging, integration, and reliability work across kernel, runtime, drivers, and UI.

Retired macOS app

GlucoGram

Dexcom Share, macOS menu bar utility

A retired macOS menu bar utility formerly distributed through the App Store for viewing live Dexcom glucose data without opening a separate app.

  • Pulls glucose data from Dexcom Share and shows current value and trend at a glance.
  • Built from a personal need to reduce context switching while working.
  • No longer maintained and retired from the App Store in 2024; included here as a concise project reference.

About

About NinetyBytes

NinetyBytes is the name I originally intended to use for an independent software company. It never became a formal company, but the name remains the umbrella I use for personal work across AI, health software, and systems engineering.

This site is intentionally selective. The goal is to show the range I work across: product-grade iOS and watchOS software, applied ML, and low-level systems engineering.

Contact

Contact

For follow-up, additional project context, or technical discussion, email is the simplest way to reach me.