Adrian Chadd
OccupationsSoftware engineer, systems architect
Known forFreeBSD development, Squid maintainer, Netflix Open Connect
TitleFreeBSD Committer
Call signKK6VQK

Adrian Chadd is an Australian software engineer and systems architect. He is a committer for the FreeBSD operating system and has worked on networking, wireless drivers, and web caching infrastructure.[1]

Professional career

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Web caching

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Chadd worked as a systems engineer at AARNet. He was a maintainer of the Squid Web Cache project for 15 years, managing the 2.7 stable branch. His work focused on the Cyclic Object Storage System (COSS).[2]

Wireless networking

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While employed at Qualcomm Atheros, Chadd rewrote driver components for the ath9k (Linux) and ath (FreeBSD) drivers, moving them from proprietary binary blobs to open-source code. This development was cited during the Free Software Foundation's "Respects Your Freedom" (RYF) certification for a wireless adapter in 2013.[3]

Content delivery and AR

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From 2013 to 2016, Chadd worked on the Netflix Open Connect Content Delivery Network. He implemented kernel optimizations, including Receive Side Scaling (RSS) and NUMA-aware networking, to improve throughput on single-socket servers.[4]

In 2018, Chadd joined Meta Platforms to work on hardware for augmented reality, specifically the Orion compute unit. His work included PCIe power management and USB transport debugging.[5]

Technical contributions

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Security: In 2014, Chadd authored a patch for a 30-year-old vulnerability in the FreeBSD TCP stack involving predictable sequence numbers, known as the "Demon bug."Chirgwin, Richard (2014-12-11). "FreeBSD developers VANQUISH Demon bug". The Register. Retrieved 2026-04-28.

Patents: Chadd is listed as an inventor on several patents regarding wireless signal processing and network architecture:

References

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  1. "Adrian Chadd - FreeBSD Wiki". FreeBSD.org. Retrieved 2026-04-28.
  2. "Adrian Chadd - Squid Web Cache Wiki". Squid-Cache.org. Retrieved 2026-04-28.
  3. gnu, joshua (2013-04-30). "FSF Certifies Atheros-Based ThinkPenguin 802.11 N USB Adapter". Slashdot. Retrieved 2026-04-28.
  4. "Software Development Projects Update". FreeBSD Foundation. Retrieved 2026-04-28.
  5. US 20210184991A1, "Systems and Methods for Network Stack", published 2021-06-17, assigned to Facebook Technologies, LLC
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