Robert O'callahan
Software Engineer at Novell, Inc.
Arcata, California, United States
Summary
🤩
Rockstar🎓
Top SchoolRobert O'callahan is a seasoned software engineer with 24 years of experience, known for deep systems and debugging expertise from stints as a Mozilla distinguished engineer and work with Google DeepMind. Based in Arcata, California, he blends low-level system engineering—contributions to the rr record-and-replay debugger and Linux PMU/kernel interactions—with high-quality open-source work on web standards like the W3C Web Audio API. He’s an active Rust contributor, enhancing libraries such as gimli (DWARF support) and octocrab (type-safe GitHub API client), demonstrating a rare cross-stack fluency from kernel internals to web APIs. Unusually for someone with his technical pedigree, his academic background is in History and Religious Studies, reflecting a broad intellectual curiosity that informs his pragmatic, specification-driven approach to engineering.
24 years of coding experience
Bachelor's degree, History/Religious Studies, Bachelor's degree, History/Religious Studies at The College of William and Mary
Github Skills (38)
javascript10
c-language10
system-programming10
apidoc10
dwarf10
api-design10
user-authentication10
authentication10
cross-platform10
linux-kernel10
web-audio-api10
api10
github-api10
rust10
performance-monitoring10
Programming languages (14)
Github contributions (5)
rr-debugger/rr
Jan 2013 - Jan 2023
Record and Replay Framework
Role in this project:
Back-end Developer & System Engineer
Back-end Developer & System EngineerContributions:22 releases, 251 reviews, 3609 commits in 10 years 1 month
Contributions summary:Robert contributed to the rr-debugger/rr repository by implementing and maintaining several low-level system functionalities. Their contributions primarily focused on enhancing performance counter capabilities and handling intricacies related to processor-specific performance monitoring units (PMUs). The user also addressed kernel compatibility and potential issues arising from interactions with other system tools or dependencies. This work involved modification of the system level interfaces of the Linux kernel and system library and likely required deep system level knowledge.
replaylinuxperformancerecord-and-replaydebugger
gimli-rs/gimli
Dec 2017 - Jun 2021
A library for reading and writing the DWARF debugging format
Role in this project:Back-end Developer
Back-end DeveloperContributions:20 commits, 12 PRs, 56 comments in 3 years 6 months
Contributions summary:Robert made significant contributions to the `gimli-rs/gimli` repository, a library for reading and writing the DWARF debugging format. They implemented support for DWARF 5 features, specifically for `.debug_rnglists` and `.debug_loclists` sections and added typed-stack DW_OPs. Additionally, they fixed attribute names and improved the library by supporting coercing Sdata to unsigned values and Udata to signed values.
dwarfpe-filerustloggingelf
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