SYSTEMS FIELD NOTES
VOL. 01 — 2026
Linux Kernel · Embedded Systems · SoC Bring-up
DUJINLABS / FIELD NOTE 001
These notes follow real source locations and boot boundaries, from the register state handed off by the bootloader through kernel initialization, device drivers, and the root file system.
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Bring-up Path
Each boot stage is tied to real code, initialization boundaries, and the state passed to the next stage.
Section 01 / Linux
Notes on kernel internals and board-dependent areas such as scheduling, memory, interrupts, device drivers, devicetree, and power management.
Linux Kernel Notes Linux 6.18.37 LTS arm64 head.S, line by line A visual walkthrough of the Image header, primary_entry, ID map, MMU enable, EL transitions, secondary CPUs, and KASLR relocation.Executable examples that use the kernel ABI from userspace: processes, threads, signals, IPC, file descriptors, mmap, epoll, and sockets.
Linux System Programming From executable code to syscalls and kernel objects Thirty-eight topics organized around runnable C programs, annotated snippets, call-flow diagrams, failure conditions, and verification experiments.Hardware
Step-by-step verification from power, reset, clocks, and physical signals through controller registers, firmware descriptions, Linux probing, and runtime paths.
Browse all hardware notesA single bring-up path through PHY/PIPE, DBI, Port Logic, LTSSM, iATU, BAR, DMA, and MSI, using Synopsys DesignWare PCIe as the reference.
From magnetics, PHY straps, MDIO, and auto-negotiation up through MAC descriptors, NAPI, and the Linux network stack.
Architecture-specific verification of the path from a device interrupt source to a CPU exception and Linux IRQ handler on Arm, RISC-V, and x86.
The complete set of 4,891 target documents has been translated and reviewed while preserving Linux 6.18.37 Documentation/ source paths and structure. Code, configuration names, ABI notation, and SPDX licenses remain unchanged.
RTOS
Technical notes on threads, scheduling, interrupts, the device model, devicetree, Kconfig, and west build flow, based on Zephyr 3.7.0 LTS3.
Browse Zephyr RTOS notesZephyr is an open-source RTOS that scales from small MCUs to SMP SoCs. These notes go beyond API summaries to trace where build-time generated objects meet runtime state transitions.
Bootloader
Initialization after ROM, storage, trusted boot, the Secure World, and kernel handoff are examined separately through U-Boot, LK, Barebox, TF-A, and OP-TEE.
v2026.07 · ARM64, x86-64, RISC-V, SPL/TPL, relocation, driver model, storage, bootflow, FIT, fastboot, Linux handoff · 22 topics
LK20 topics separating the upstream LK core from classic AOSP aboot: threads, timers, apps, Android boot images, and fastboot
Bareboxv2026.06.1 · PBL, initcall, device model, devfs, environment/state, bootchooser, bootm, BBU · 19 topics
Trusted Firmware-ALTS 2.14.3 · FIP, BL1/BL2/BL31, Chain of Trust, EL3 runtime service, PSCI, GIC, BL32/BL33 handoff · 12 topics
OP-TEE4.10.0 · S-EL1 entry, MMU/pager, secure thread, SMC message, TA session, secure storage, RPC · 12 topics
File System
VFS, block layer, ext4, f2fs, initramfs, mount, overlay, partition layout, and device-node configuration.
Reading Notes
Reading notes on computer architecture, operating systems, Linux, embedded systems, and electronics, connecting each book's main arguments to real implementations and practical scope.
Board Design
PCB design notes from schematics through stack-up, placement, routing, power and signal integrity, DFM, and board bring-up.
Intelligent Systems
From model architecture and training principles to inference runtimes, accelerators, edge deployment, and Linux-based AI systems.
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