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finishing.txt

Guest on 6th September 2021 09:38:22 AM

  1. http://www.ibm.com/developerworks/library/l-linuxboot/
  2. https://en.wikipedia.org/wiki/Linux_startup_process
  3. https://en.wikipedia.org/wiki/Initrd
  4.  
  5. Boot process....
  6.  
  7. CPU will execute at reset vector
  8.   https://en.wikipedia.org/wiki/Reset_vector
  9.     (0xFFFFFFF0)
  10. Intel reference manual
  11.   http://download.intel.com/products/processor/manual/325462.pdf
  12.   http://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-manual-325462.html
  13.  
  14. IntelĀ® 64 and IA-32 Architectures Software Developerā€™s Manual
  15.   First Instruction Executed -- Section 9.1.4  (Vol 3A  9-5)
  16.     0xFFFFFFF0 (FFFFFFF0H)   -- in EPROM
  17.  
  18. S/360 -- IPL (Initial Program Load)
  19.   computer operator sets three hex address and presses LOAD
  20.   loads 24 bytes --
  21.     initial PSW and two CCW
  22.  
  23. first stage boot loader (BIOS or UEFI)
  24.   generally can specify boot order
  25. Won't turn on .... count the beeps...
  26.   POST (Power-On Self-Test)
  27.     memory failure
  28.     power supply
  29.  
  30. https://en.wikipedia.org/wiki/Power-on_self-test
  31.   After power turned on, POST is run (generally handled by BIOS)
  32. In later BIOS, POST discovers system buses
  33.  
  34. BIOS (UEFI) ā†’ MBR ā†’ grub ā†’ Kernel ā†’ init  
  35.  
  36. http://askubuntu.com/questions/592740/how-does-the-ubuntu-boot-process-work
  37.   bootchart
  38.  
  39. **************** BIOS
  40. BIOS loads boot sector
  41.   GUID Partition Table replacing MBR (Master Boot Record)
  42. MBR contains "bootstrap code" (~400 bytes)
  43.   loaded into memory at location 0 (could be up to ~32000 bytes)
  44. VBR -- volume boot record (on each partition)
  45.  
  46. second stage boot loader (GNU GRUB)
  47.     network boot ... uses TFTP
  48.  
  49. GRUB and LILO write to MBR sector (grub-install)
  50.  
  51. GUID Partition Table
  52.   https://en.wikipedia.org/wiki/GUID_Partition_Table
  53.  
  54.  
  55. "tuning" kernel for Oracle
  56.  
  57. http://www.howtogeek.com/56958/htg-explains-how-uefi-will-replace-the-bios/
  58.  
  59. Linux bootloaders -- LILO replaced by GRUB
  60.  
  61.  
  62. https://wiki.ubuntu.com/Booting
  63. https://help.ubuntu.com/community/UEFI
  64.  
  65. https://help.ubuntu.com/community/UEFI
  66.  
  67. BIOS to GRUB
  68.   generally /boot/grub/i386-pc (or /boot/grub/x86_64-efi) contains
  69.     boot.img
  70.       written to boot sector -- 512 bytes
  71.       loads first part of core.img and jumps to it
  72. http://git.savannah.gnu.org/cgit/grub.git/tree/grub-core/boot/i386/pc/boot.S
  73.     core.img
  74.       able to access /boot/grub and loads modules
  75.       *.mod stored in /boot/grub
  76.     UEFI uses core.efi and grub.efi
  77.   usually you leave grub alone
  78.     Some modifications in lab to make more secure
  79. Customizing GRUB
  80.   /usr/sbin/update-grub
  81.   /usr/sbin/grub-mkconfig
  82.   looks at /etc/grub.d
  83.  
  84. Where is kernel located....
  85.     cat /proc/cmdline
  86.     which points to eventually gets to /boot
  87.     But look in
  88.       /lib/modules/*/kernel
  89.       initrd (initial ramdisk)
  90. http://www.ibm.com/developerworks/library/l-linuxboot/
  91.  
  92. cd /var/tmp
  93. mkdir initrd
  94. cd initrd
  95. gunzip < /boot/initrd.img-3.13.0-100-generic | cpio -id
  96. du -s *
  97.  
  98. Take a look at
  99.    bin directory
  100.      what is busybox????
  101.    init shellscript
  102.      it will call /bin/run-init to run /sbin/init
  103.    It is process #1
  104.  
  105. http://upstart.ubuntu.com
  106.  
  107. https://en.wikipedia.org/wiki/Init
  108. https://en.wikipedia.org/wiki/Systemd
  109.  
  110. systemd is the future -- (dragged screaming)
  111.   Fedora , Red Hat , Debian/Ubuntu/Raspbian
  112.   many do use System V compatiability modes
  113.  
  114.  
  115.  
  116.  
  117.  
  118.  
  119.  
  120. Types of "internal hard drives"  --- Amazon
  121.   SATA
  122.  
  123. Fibre Channel (which doesn't require fiber)
  124.  
  125. https://www.usenix.org/conference/lisa16/conference-p

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