Component architect of Networking, Sound System, Voice Recognition & TTS integration, and several core components (such as scheduler).
I was a member of the Architect Board until its merge into the Engine Core Team (which I am a member of currently).

I created (the version that is currently in use in iGO) and maintained the following
components:
● Thread handling and scheduling.
○ Reactor pattern based architecture
○ Callbacks between threads, timers, event handlers, render timing,
background task handling.
○ Low level part ported to: win32 and Posix
● Application startup / shutdown handling
● Synchronous event sending
○ Component to component, component to UI script, and UI script to
component.
● Voice recognition engine integration
● TTS engine integration
● Audio focus handling
● Audio playback handling (not original creation, rewrite for about 70% of code)
○ Low level part ported to: win32 and QNX (using Alsa).
● Low/mid level networking
○ Abstraction needed for enabling the higher networking levels to handle
sockets, bluetooth, various usb connections (simulating “ports” with
multiplexer)
○ OpenSSL integration
○ Ported socket handling to win32 and Posix.
● HTTP Client
○ Capable of using native HTTP APIs where available / enabled. Using low level network abstraction otherwise.
○ Capable of switching between connections in case of error (for example when
headunit in car is connected to smartphone via both wifi and usb cable)
● HTTP Server
● HTTP Proxy
● ‘Bingo’ (NNG specific network protocol) client
● DownloadManager
● Remote debugging server
○ Exposes various internal components through HTTP (logging, model system,
scheduler, script execution, …)
● Synctool (used for reporting the state of and updating content files on headunits)

Smartexecution was a small (started with 3 employees, peaked at 10) automated trading company.

I designed, wrote and maintained almost everything except for the trading algorithms, and later a couple of book feed protocols.
We traded on: Island (later called Instinet), Arca, Brut, Nasdaq. After the first few months of trading we achieved and could maintain a daily volume of more than 30 million shares (our best day was over 100 million shares). During the 4 years of trading the only day we lost money was 9/11.
Of the 4 years of trading we were the fastest for about 3 years (based on our position in the queue after price changes) on Island ECN, where we generated most of our volume.

The main components of the architecture were:
● Trader designed for speed, taking advantage of multiple cores.
● Algorithm optimizing simulator.
● Manual trader application with GUI for entering/cancelling orders.
● Remote monitoring/controlling application with GUI.
● Order validating proxy: checking every order the trader sends, and disconnecting
from exchange(s) in case of any error is detected. The proxy was rigorously tested
with unit tests.
● Exchange simulators (book feed + order handling) for testing purposes.