100: Nathanael Huffman

Date: 2024-03-27

Duration: 01:47:46

Nathanael Huffman joins to talk about the magic of FPGAs, the role they play in domains ranging from medical imaging to data centers, and how software development principles can be applied to logic design. We also discuss how Nathanael and the team at Oxide Computer Company built a new rack-scale computer while working remotely, and what exactly happens when it powers on and boots up.

Nathanael on LinkedIn: https://www.linkedin.com/in/nathanael-huffman-5128024a/

Nathanael on X: https://twitter.com/SyntheticGate

Nathanael on Mastodon: https://hachyderm.io/@SyntheticGate

Show Notes

Welcome Nathanael (00:01:04)
Connecting via Oxide and Friends (00:01:10)
- https://oxide.computer/podcasts/oxide-and-friends
Learning about Circuits and Electronics (00:02:10)
Electrical Engineering vs. Computer Engineering (00:04:12)
Attending Purdue University (00:05:21)
- https://engineering.purdue.edu/Engr
Purdue Engineering Co-op (00:05:41)
- https://engineering.purdue.edu/ENE/Academics/Undergrad/MDE/mde-coop
GE Healthcare (00:07:17)
- https://www.gehealthcare.com/
Theory vs. Practice (00:07:58)
Field Programmable Gate Arrays (FPGAs) (00:09:23)
- https://en.wikipedia.org/wiki/Field-programmable_gate_array
The Magic of FPGAs (00:11:05)
The Value of FPGAs in Medical Context (00:14:52)
Computed Tomography (CT) Scanners (00:16:14)
- https://en.wikipedia.org/wiki/CT_scan
Filtered Back Projection (FBP) (00:16:48)
- https://en.wikipedia.org/wiki/Tomographic_reconstruction
- https://howradiologyworks.com/filtered-backprojection-fbp-illustrated-guide-for-radiologic-technologists/
Peripheral Component Interconnect eXtended (PCI-X) (00:17:52)
- https://en.wikipedia.org/wiki/PCI-X
Slip Rings (00:19:41)
- https://www.grandslipring.com/slip-ring-technology-in-ct/
8b/10b Encoding (00:19:54)
- https://en.wikipedia.org/wiki/8b/10b_encoding
AC Coupling (00:20:05)
- https://www.analog.com/en/resources/technical-articles/advantages-of-accoupling-in-serdes-applications.html
- https://community.sw.siemens.com/s/article/ac-and-dc-coupling-what-s-the-difference
64b/66b Encoding (00:21:17)
- https://en.wikipedia.org/wiki/64b/66b_encoding
Soft Core Processors (00:21:56)
- https://en.wikipedia.org/wiki/Soft_microprocessor
Filtered Back Projection on GPUs (00:23:31)
TCP Offload with FPGAs (00:24:03)
FPGA Vendors (00:24:49)
Altera (00:24:57)
- https://en.wikipedia.org/wiki/Altera
Team Composition at GE Healthcare (00:26:18)
Writing Software for Soft Cores (00:27:34)
FPGA Programming Process (00:28:33)
- https://f4pga.readthedocs.io/en/latest/how.html
Parallel NOR Flash (00:28:57)
- https://en.wikipedia.org/wiki/Flash_memory#Distinction_between_NOR_and_NAND_flash
Complex Programmable Logic Device (CPLD) (00:29:02)
- https://en.wikipedia.org/wiki/Complex_programmable_logic_device
Serial NOR Flash (00:29:38)
Quad Serial Peripheral Interface (QSPI) (00:29:43)
- https://www.arasan.com/blog/understanding-serial-peripheral-interface-spi-standards-a-comprehensive-overview/
- https://en.wikipedia.org/wiki/Serial_Peripheral_Interface#Quad_SPI
Bitstreams (00:30:13)
- https://en.wikipedia.org/wiki/Bitstream
Hardware-in-the-Loop Continuous Integration (00:30:45)
- https://en.wikipedia.org/wiki/Hardware-in-the-loop_simulation
Applying Software Development Principles to Hardware (00:31:51)
FPGA Build Times (00:34:10)
Logic Elements (LEs) (00:34:22)
- https://www.intel.com/content/www/us/en/programmable/quartushelp/17.0/reference/glossary/def_logelem.htm
GitHub Actions (00:35:37)
- https://github.com/features/actions
Vivado (00:35:45)
- https://en.wikipedia.org/wiki/Vivado
Quartus (00:35:46)
- https://en.wikipedia.org/wiki/Intel_Quartus_Prime
GitHub Self-Hosted Runners (00:36:33)
- https://docs.github.com/en/actions/hosting-your-own-runners/managing-self-hosted-runners/about-self-hosted-runners
Raspberry Pi (00:36:49)
- https://www.raspberrypi.com/
Steps in Generating a Bitstream (00:37:26)
Phases of an FPGA Build (00:38:00)
- https://fpgatutorial.com/fpga-build-process/
Register-Transfer Level (00:38:09)
- https://en.wikipedia.org/wiki/Register-transfer_level
Verilog & VHDL (00:38:14)
- https://en.wikipedia.org/wiki/Verilog
- https://en.wikipedia.org/wiki/VHDL
Analysis & Elaboration (00:38:23)
Synthesis (00:39:01)
- https://en.wikipedia.org/wiki/Logic_synthesis
Karnaugh Maps (00:39:20)
- https://en.wikipedia.org/wiki/Karnaugh_map
Place & Route (00:39:37)
- https://en.wikipedia.org/wiki/Place_and_route
Configurable Logic Block (CLB) (00:40:17)
- https://en.wikipedia.org/wiki/Logic_block
Adaptive Logic Module (ALM) (00:40:19)
- https://www.intel.com/content/www/us/en/programmable/quartushelp/17.0/reference/glossary/def_alm.htm
Lookup Table (LUT) (00:40:21)
- https://en.wikipedia.org/wiki/Lookup_table
Flip Flops (FF) (00:40:22)
- https://en.wikipedia.org/wiki/Flip-flop_(electronics)
Simulated Annealing (00:40:57)
- https://en.wikipedia.org/wiki/Simulated_annealing
Building the Bitstream (00:41:53)
Timing Constraints (00:41:58)
- https://www.latticesemi.com/en/Blog/2021/06/07/18/52/ImportanceofTimingConstraints
Jenkins (00:43:11)
- https://www.jenkins.io/
Incremental Compilation (00:43:34)
- https://en.wikipedia.org/wiki/Incremental_compiler
Reproducible Builds (00:43:54)
- https://en.wikipedia.org/wiki/Reproducible_builds
Deterministic FPGA Builds (00:44:44)
Setup and Hold Times (00:45:26)
- https://nandland.com/lesson-12-setup-and-hold-time/
Fitter Initial Placement Seed (00:45:38)
- https://www.intel.com/content/www/us/en/docs/programmable/683145/21-3/change-fitter-placement-seeds.html
Optimizing Resource Usage and Timing (00:47:14)
Design Partitioning (00:49:05)
Reducing Counter Width (00:50:34)
- https://en.wikipedia.org/wiki/Counter_(digital)
Vendor IP (00:52:04)
- https://en.wikipedia.org/wiki/Semiconductor_intellectual_property_core
Serial RapidIO (00:52:35)
- https://en.wikipedia.org/wiki/RapidIO
Peripheral Component Interconnect Express (PCIe) (00:54:39)
- https://en.wikipedia.org/wiki/PCI_Express
FIFOs (00:54:51)
- https://en.wikipedia.org/wiki/FIFO_(computing_and_electronics)
Dual-Port RAMs (00:55:04)
- https://en.wikipedia.org/wiki/Dual-ported_RAM
Designing for Portability (00:56:05)
Why Serial RapidIO? (00:57:41)
SerDes (00:58:02)
- https://en.wikipedia.org/wiki/SerDes
Star Topology (00:58:49)
- https://en.wikipedia.org/wiki/Star_network
Ethernet (00:59:31)
- https://en.wikipedia.org/wiki/Ethernet
Clock Data Recovery (CDR) (01:00:53)
- https://en.wikipedia.org/wiki/Clock_recovery
Physical Layer Retransmission (01:03:47)
User Datagram Protocol (UDP) (01:04:12)
- https://en.wikipedia.org/wiki/User_Datagram_Protocol
The Value of Controlling the Whole System (01:05:30)
Updating CT Scanners in the Field (01:07:38)
Update Frequency (01:08:27)
The Value of Working on Complex Systems (01:10:18)
Oxide Computer Company (01:12:37)
- https://oxide.computer/
Bringing the Cloud Native Experience to On-Prem (01:12:58)
- https://en.wikipedia.org/wiki/Cloud-native_computing
AMD Milan (01:14:13)
- https://en.wikipedia.org/wiki/Epyc#Third_generation_Epyc_(Milan)
Decision to Join Oxide (01:14:48)
HackerNews (01:14:50)
- https://news.ycombinator.com/
Compensation as a Reflection of Values (01:15:28)
- https://oxide.computer/blog/compensation-as-a-reflection-of-values
Oxide Application Process (01:16:48)
- https://oxide.computer/careers
Bryan Cantrill (01:16:58)
- https://en.wikipedia.org/wiki/Bryan_Cantrill
- https://bcantrill.dtrace.org/
State of the Oxide Rack in 2021 (01:18:00)
Focus on Ownership (01:19:20)
Gimlet Server Board (01:20:31)
- https://docs.oxide.computer/guides/architecture/service-processors#_server_sled
Oxide and Friends Hardware Bringup Episodes (01:21:15)
- https://oxide.computer/podcasts/oxide-and-friends/838573
- https://oxide.computer/podcasts/oxide-and-friends/875000
- https://oxide.computer/podcasts/oxide-and-friends/1008496
Working on Hardware in a Remote Company (01:21:25)
Benchmark Electronics (01:22:47)
- https://www.bench.com/rochester-minnesota
Picking Up Servers in a Cheese Store Parking Lot (01:22:53)
Is Oxide Reinventing the Wheel? (01:24:11)
Handling Customer Support Cases (01:25:19)
Building Big Systems with Remote Hardware Teams (01:26:20)
- https://oxide.computer/blog/building-big-systems-with-remote-hardware-teams
What Happens when an Oxide Rack Powers On? (01:26:31)
- https://docs.oxide.computer/guides/system/initial-rack-setup#_upload_software_to_the_rack
Illumos (01:28:26)
- https://illumos.org/
How does the Oxide Computer Boot? (01:28:55)
- https://oxide.computer/podcasts/oxide-and-friends/1084759
Lattice iCE40 FPGA (01:29:29)
- https://www.latticesemi.com/Products/FPGAandCPLD/iCE40Ultra
Double Date Rate Memory (DDR) (01:29:44)
- https://en.wikipedia.org/wiki/Double_data_rate
Power Management Bus (PMBus) (01:29:49)
- https://en.wikipedia.org/wiki/Power_Management_Bus
AMD Platform Security Processor (PSP) (01:30:07)
- https://en.wikipedia.org/wiki/AMD_Platform_Security_Processor
DDR Training (01:30:19)
- https://www.systemverilog.io/design/ddr4-initialization-and-calibration/
Dual In-Line Memory Module (DIMM) (01:30:24)
- https://en.wikipedia.org/wiki/DIMM
Pico Host Boot Loader (PHBL) (01:30:42)
- https://github.com/oxidecomputer/phbl
Unified Extensible Firmware Interface (UEFI) (01:31:05)
- https://en.wikipedia.org/wiki/UEFI
Oxide Service Processor (SP) (01:31:31)
- https://docs.oxide.computer/guides/architecture/service-processors
Hubris Embedded OS (01:31:39)
- https://hubris.oxide.computer/
Oxide Sled Power States (01:31:57)
Ignition FPGA (01:32:09)
Fan Control (01:34:50)
Open Source FPGA Toolchains (01:35:08)
- https://f4pga.org/
Open Source vs. Proprietary FPGA Toolchains (01:35:40)
Reverse Engineering FPGA Chips (01:36:18)
- https://f4pga.readthedocs.io/projects/arch-defs/en/latest/index.html
Yosys (01:37:19)
- https://github.com/YosysHQ/yosys
ChipScope and Signal Tap (01:37:49)
- https://www.xilinx.com/products/intellectual-property/chipscope_ila.html
- https://learning.intel.com/developer/learn/courses/203/signal-tap-logic-analyzer-introduction-getting-started
Timing Analysis (01:39:40)
QuickLogic (01:41:50)
- https://www.quicklogic.com/
Renesas GreenPAK (01:42:02)
- https://en.wikipedia.org/wiki/GreenPAK
What’s Next for Oxide? (01:43:34)
Scaling up Production Lifecycle (01:43:55)
Next-Gen Server Sled (01:44:32)
Unifying the Dongles (01:45:35)

Transcript

Coming soon.