Certification Objective 3.03Understanding BIOS Settings and Configuration

Certification Objective 3.03—Understanding BIOS Settings and Configuration

Exam Objective 3.2: Given a scenario, explain the BIOS settings for booting, abort sequence, and displaying POST, including BIOS configuration for x64 and x86-based system.

Like SPARC machines, x86 (PC) machines go through a booting process before the Solaris operating system takes control of the machine. The read-only memory that contains the boot instructions is called the Basic Input/Output System (BIOS) in an x86 machine as opposed to Boot PROM in a SPARC machine. The functions of the BIOS include controlling installed peripheral devices such as keyboard and mouse and to providing I/O services via software interrupts.

The phases of the boot process on an x86 machine are described here:

• BIOS. When the system is turned on, the BIOS runs the self-test diagnostics program for the system's hardware and memory. If problems are found, the error messages are displayed with recovery options. If no errors are found, the BIOS boot program is started automatically, and it attempts to find and load what is called the master boot record (MBR), mboot, from the first sector in the boot device. An error is displayed if the mboot file does not exist.

• Boot programs. The mboot program loads the Solaris boot program called pboot, which in turn loads the primary boot program, bootblk, whose purpose is to load the secondary boot program located in the UFS file system. If there are more than one bootable partitions on the system, the bootblk reads the fdisk table to determine the default boot partition. It builds and displays a menu of available partitions and gives you 30 seconds to select an alternative partition to boot from. The primary boot program—bootblk—starts the secondary boot program boot.bin or ufsboot in the root file system, which in turn starts a command interpreter that executes the /etc/bootrc script. This script presents a menu of choices for booting the system, and you have 5 seconds to specify a boot option or to start the boot interpreter. The default choice is to load the kernel.

• Kernel initialization. After the kernel has been loaded, it initializes itself and uses the secondary boot program boot.bin (or ufsboot) to load system modules. When the kernel loads enough modules to mount the root (/) file system, it unmaps the secondary boot program and continues taking over the system. It creates a user process and starts the /sbin/init process, which then starts other processes by reading the /etc/inittab file.

• init. In Solaris 10, the init process starts /lib/svc/bin/svc.startd, which in turn starts system services to perform the following tasks:

  • Check and mount file systems

  • Configure network and devices

  • Start various processes and perform system maintenance tasks

The svc.startd daemon also executes the run control (rc) scripts for backward compatibility. During the booting process, you have some control over the way in which the system is booted. Two menus are displayed for you: the Boot Solaris menu and the Current Boot Parameters menu.

The Boot Solaris menu allows you to select the device from which to boot the Solaris OS. At this point, you can also perform some optional tasks such as viewing and editing autoboot and property settings. Once you select a boot device and choose Continue, the Solaris kernel begins to boot. The menu looks like the following:

 Boot Solaris Select one of the identified devices to boot the Solaris kernel and choose Continue. To perform optional features, such as modifying the autoboot and property settings, choose Boot Tasks. An asterisk (*) indicates the current default boot device. > To make a selection use the arrow keys, and press Enter to mark it [X]. [X] DISK: (*) Target 0:QUANTUM FIREBALL1280A on Bus Mastering IDE controller on Board PCI at Dev 7, Func 1 [ ] DISK: Target 1:ST5660A on Bus Mastering IDE controller on Board PCI at Dev 7, Func 1 [ ] DISK: Target 0:Maxtor 9 0680D4 on Bus Mastering IDE controller on Board PCI at Dev 7, Func 1 [ ] CD : Target 1:TOSHIBA CD-ROM XM-5602B 1546 on Bus Mastering IDE controller on Board PCI at Dev 7, Func 1 F2_Continue F3_Back F4_Boot Tasks F6_Help 

The second menu that you are offered is the current boot parameter menu, which looks like the following:

    <<< Current Boot Parameters >>>    Boot path: /pci@0,0/pci-ide@7,l/ide@0/cmdk@0,0:a    Boot args:    Type b [file-name] [boot-flags] <ENTER> to boot with options    or i <ENTER> to enter boot interpreter    or <ENTER> to boot with defaults    <<< timeout in 5 seconds >>>    Select (b)oot or (i)nterpreter: 

The following file contains the eeprom variables used to set up the boot environment on an x86 machine:

    /boot/solaris/bootenv.rc 

All directories and files needed to boot an x86-based system are contained in the /boot directory.

In addition to BIOS configurations, there may be situations in which you will need to configure (or reconfigure) some devices such as keyboard, display, and mouse.