Daniel Jackowitz Email & Phone Number

New York, Ny, Us

New York, Ny, Us

New York, Us

During my time at Tumblr I've made contributions at just about every layer of the data stack:• Giving client-side analytics a much-needed update that included a unified schema, a high-volume Scala event ingestion service, and real-time exploratory analytics using Apache Kafka and Apace Druid.• Leveraging deep Hadoop platform knowledge, along with custom UDFs and other extensions to Hive and Scalding, to optimize ETLs and offline jobs, often by orders of magnitude.• Shepherding the adoption of Apache Airflow, leading by example with DAG and custom operator implementations and advising engineers across many teams on best practices. • Increasing observability of critical platforms via a Prometheus-to-Hadoop (and others) proxy bridge.• Migrating Tumblr's data infrastructure from a Yahoo! datacenter to an Automattic datacenter.

New York, Ny, Us

My major contribution in this role was an "in-place" rewrite of key components of The New York Times push notification system with the goal of improving overall reliability and total send times, particularly for the 1-to-millions fanout "Breaking News" notifications. With some careful non-blocking PHP socket programming (i.e. C bindings) in critical loops that interfaced with the Google (GCM/FCM) and Apple (APNS) services I improved total send times by over 60x - from minutes to seconds - achieving the project goals in well under the time budgeted for a planned full rewrite and with no disruption to dependent systems.

CS 422/522: Operating Systems▪ Senior/graduate-level Operating Systems course based on the MIT 6.828 JOS exokernel.▪ Core topics: The bootloader, virtual memory, processes, scheduling, E1000 network driver▪ Responsibilities: Office hours, grading assignments, and contributing to the design of assignments and exams. I additionally presented a lecture covering the topics of advanced multi-processor coordination and lock-free data structures.Technologies Used: C, x86 Assembly (AT&T), QEMU VMM

Scranton, Pa, Us

Day-to-day maintenance and damage control for the departmental machines.▪ 13 servers (FreeBSD)▪ Intra-department network▪ 20+ Windows RDP ThinClientsBuilt, configured and deployed a new 4-node MongoDB cluster within the department and presented a lecture on the system for the graduate database course.Technologies Used: FreeBSD, Ubuntu, PostgreSQL, Git, CVS, Apache, MongoDB, Cisco IOS

Scranton, Pa, Us

C/IL 102L: Computer Literacy Lab▪ Core topics: Microsoft Office, image processing, and basics of website design.▪ Responsibilities: designing assignments, short lectures, and grading student submissions.Technologies Used: Microsoft Office, GIMP, KompoZer

Designed and developed an Android application to act as a wireless upload station for the Fleet Genius custom On Board Diagnostics (OBD-II) device for fleet vehicle management. The application connects to the custom hardware via Bluetooth and provides configuration and data retrieval via a binary protocol. The app performs pre-processing on the vehicle data and uploads the result to the Fleet Genius web application.Technologies Used: Android 2.3.3 and 4.0, ODB-II, Bluetooth

Designed and developed two Android applications for demoing a new mobile screen technology. The applications themselves were outwardly simplistic (a "Simon"-like color/sound game and a MS Paint-like canvas drawing app) but behind-the-scenes recorded and processed data about touchscreen interactions and relayed this data to external hardware via an IOIO for Android USB peripheral.Technologies Used: Android 2.3.3 and 4.0, IOIO board for Android

Interned over multiple semester breaks, working on a several projects related to the Pario SaaS architecture for code-free development of business applications:Performance and Stress Testing▪ Developed a multi-threaded Java application to simulate 1000s of concurrent clients▪ Manipulated JSON to automate test case generation from templates and responses. ▪ Identified key performance bottlenecks, which I worked with the chief architect to resolve.Regression Testing Automation▪ Developed suite for identifying regressions in Pario's data aggregation layer ("calc fields").▪ Java client interacted with Pario via a JSON API to create projects, insert bulk data, and verify the results of aggregation queries on the data without user interaction.Porting For Google App Engine▪ Ported core components of the PHP/PostgreSQL Pario backend to Java/MySQL for a prototype deployment on Google App Engine.Technologies Used: Java, Google Web Toolkit, PHP, PostgreSQL, MySQL, JSON

Master Of Science (M.S.), Computer Science

Master Of Science (M.S.), Software Engineering

Bachelor Of Science (B.S.), Computer Science, Electrical Engineering, Computer Engineering