Some graphs of the ubuntu boot sequence

ubuntu-classic-boot.dot

# Build with dot -Tpng ubuntu-classic-boot.dot | display png:-

digraph G {
    graph [rankdir=TB];
    node [fontsize=10, fontname="Arial"];
    edge [fontsize=10, fontname="Arial"];

    /* files */
    node [shape=rect, style=filled, fillcolor="#7ec2cc", penwidth=0];
    bootcode_bin [label="/boot/bootcode.bin"];
    device_tree [label="/boot/bcm*.dtb"];
    start_elf [label="/boot/start*.elf;\n/boot/fixup*.dat"];
    initrd_img [label="/boot/initrd.img"];
    kernel_img [label="/boot/vmlinuz"];
    uboot_bin [label="/boot/uboot*.bin"];
    config_txt [label="/boot/config.txt"];
    cmdline_txt [label="/boot/cmdline.txt"];
    boot_scr [label="/boot/uboot.env\nor\n/boot/boot.scr"];
    //uboot_env [label="/boot/uboot.env"];
    flash_kernel [label="/usr/sbin/flash-kernel"];

    /* processes */
    node [shape=parallelogram, fillcolor="#f54e4e", penwidth=0];
    bootcode_bin_exe [label="bootcode.bin"];
    start_elf_exe [label="start*.elf"];
    initrd_img_exe [label="initrd.img"];
    kernel_img_exe [label="vmlinuz"];
    uboot_bin_exe [label="uboot*.bin"];
    device_tree_mem [label="<device-tree>", fillcolor="#e09392"];

    /* packages */
    node [shape=ellipse, fillcolor="#7ec27e", penwidth=0];
    base [label="base image"];
    linux_firmware [label="linux-firmware-raspi2"];
    linux_modules [label="linux-modules-*-raspi2"];
    initramfs_tools [label="initramfs-tools"];
    flash_kernel_pkg [label="flash-kernel"];
    kernel [label="linux-image-*"];
    uboot [label="u-boot-rpi"];

    edge [style=bold, label="runs"];
    bootcode_bin_exe->start_elf_exe;
    start_elf_exe->uboot_bin_exe;
    start_elf_exe->device_tree_mem [label="creates"];
    uboot_bin_exe->kernel_img_exe;
    kernel_img_exe->initrd_img_exe;

    edge [style=solid, label="contained\nin"];
    flash_kernel->flash_kernel_pkg;
    boot_scr->flash_kernel_pkg;
    bootcode_bin->linux_firmware;
    cmdline_txt->base;
    config_txt->base;
    device_tree->linux_modules;
    initrd_img->initramfs_tools;
    kernel_img->kernel;
    start_elf->linux_firmware;
    uboot_bin->uboot;

    edge [style=dashed, label="installed\nby"];
    boot_scr->flash_kernel;
    bootcode_bin->linux_firmware;
    cmdline_txt->uboot [label="modified\nby"];
    config_txt->uboot [label="modified\nby"];
    device_tree->flash_kernel;
    initrd_img->flash_kernel;
    kernel_img->flash_kernel;
    start_elf->linux_firmware;
    uboot_bin->uboot;

    edge [style=solid, label="refs"];
    config_txt->cmdline_txt;
    config_txt->uboot_bin;
    config_txt->kernel_img;
    config_txt->initrd_img;
    boot_scr->kernel_img;
    boot_scr->initrd_img;

    edge [style=solid, label="uses"];
    bootcode_bin_exe->config_txt;
    bootcode_bin_exe->bootcode_bin;
    start_elf_exe->config_txt;
    start_elf_exe->cmdline_txt;
    start_elf_exe->start_elf;
    start_elf_exe->device_tree;
    uboot_bin_exe->uboot_bin;
    kernel_img_exe->kernel_img;
    initrd_img_exe->initrd_img;

    uboot_bin_exe->boot_scr;
    uboot_bin_exe->device_tree_mem;
    kernel_img_exe->device_tree_mem;
    start_elf_exe->device_tree_mem;
}