Solaris Open Boot

The primary function of the OpenBoot firmware is to start up the system. Starting up is the process of loading and executing a standalone program (for example, the operating system or the diagnostic monitor). In case of Solaris the standalone program that is being started is the two-part operating system kernel. After the kernel is loaded, the kernel starts the Solaris OS, mounts the necessary file systems, and runs /sbin/init  to bring the system to the initdefault  state that is specified in /etc/inittab. Stages of this process is known as "System Run States".

The OpenBoot architecture consists of the following components:

• Plug-in device drivers—A device driver can be loaded from a plug-in device such as an SBus card. The plug-in device driver can be used to boot the operating system from that device or to display text on the device before the operating system has activated its own software device drivers. This feature lets the input and output devices evolve without changing the system PROM.
   
• The FCode interpreter—Plug-in drivers are written in a machine-independent interpreted language called FCode. Each OpenBoot system PROM contains an FCode interpreter. This enables the same device and driver to be used on machines with different CPU instruction sets.

  The OpenBoot user interface is based on the programming language Forth, which provides an interactive programming environment. Forth is used for direct communication between humans and machines. It can be quickly expanded and adapted to special needs and different hardware systems. Forth is used not only by Sun but also by other hardware vendors such as Hewlett-Packard.
   

• The device tree—Devices called nodes are attached to a host computer through a hierarchy of interconnected buses on the device tree.
  • A node representing the host computer's main physical address bus forms the tree's root node. Both the user and the operating system can determine the system's hardware configuration by viewing the device tree.
  • Nodes with children usually represent buses and their associated controllers, if any. Each such node defines a physical address space that distinguishes the devices connected to the node from one another. Each child of that node is assigned a physical address in the parent's address space. The physical address generally represents a physical characteristic that is unique to the device (such as the bus address or the slot number where the device is installed). The use of physical addresses to identify devices prevents device addresses from changing when other devices are installed or removed.

The normal Solaris boot process has five main phases:

1. Basic hardware detection (memory, disk, keyboard, mouse, and the like) and executing the firmware system initialization program .  In Solaris this is called Boot PROM phase—After you turn on power to the system, the PROM displays system identification information and runs self-test diagnostics to verify the system's hardware and memory. PROM chip contains Forth OpenBoot firmware, and it is executed immediately after you turn on the system. The primary task of the OpenBoot firmware is to boot the operating system either from a mass storage device or from the network. OpenBoot contains a program called the monitor that controls the operation of the system before the kernel is available. When a system is turned on, the monitor runs a power-on self-test (POST) that checks such things as the hardware and memory on the system.  If no errors are found, the automatic boot process begins. OpenBoot contains a set of instructions that locate and start up the system's boot program and eventually start up the Unix operating system.
    

2. Locating and running the initial boot program (IPL or bootloader) from a predetermined location on the disk (MBR in PC). In Solaris the primary boot program, called bootblk, is loaded from its location on the boot device (usually disk) into memory.
    

3. Locating and starting the Unix kernel. The kernel image file to execute may be determined automatically or via input to the bootloader. In Solaris the bootblk  program finds and executes the secondary boot program (called ufsboot) from the Unix file system (UFS) and loads it into memory. After the ufsboot  program is loaded, the ufsboot  program loads the two-part kernel.
    

4. The kernel initializes itself and then performs final, high-level hardware checks, loading device drivers and/or kernel modules as required.  In Solaris the kernel initializes itself and begins loading modules, using ufsboot  to read the files. When the kernel has loaded enough modules to mount the root file system, it unmaps the ufsboot  program and continues, using its own resources.
    

5. The kernel starts the init process, which in turn starts system processes (daemons) and initializes all active subsystems. When everything is ready, the system begins accepting user logins. In Solaris kernel starts the Unix operating system, mounts the necessary file systems, and runs /sbin/init  to bring the system to the initdefault  state specified in /etc/inittab. The kernel creates a user process and starts the /sbin/init  process, which starts other processes by reading the /etc/inittab  file. The /sbin/init  process starts the run control (rc) scripts, which execute a series of other scripts. These scripts (/sbin/rc*) check and mount file systems, start various processes, and perform system maintenance tasks.

NEWS CONTENTS

• 210210 : PCI System Commands ( PCI System Commands , )
• 210210 : Updating OpenBoot PROM for Sun Workstations and Workgroup Servers ... ( Updating OpenBoot PROM for Sun Workstations and Workgroup Servers ..., )
• 210210 : How to Perform System Boot and Shutdown Procedures for Solaris 10 ... ( How to Perform System Boot and Shutdown Procedures for Solaris 10 ..., )
• 210210 : Debugging Solaris using Open Boot Prom ( Debugging Solaris using Open Boot Prom, )
• 210210 : Solaris 9 System Startup and Shutdown > The OpenBoot Architecture ( Solaris 9 System Startup and Shutdown > The OpenBoot Architecture, )
• 210210 : OpenBoot > OpenBoot Environment ( OpenBoot > OpenBoot Environment, )
• 210210 : Open Boot Parameters Adminschoice.com ( Open Boot Parameters Adminschoice.com, )

Old News ;-)

PCI System Commands

The following user query and control commands (forth words) are available on PCI based systems.

Use the show-pci-devs command to show all devices on a specific PCI bus.

ok show-pci-devs /pci@1f,2000 (show pcia devices)

ok show-pci-devs /pci@1f,4000 (show pcib devices)

Use the show-pci-devs-all command to show all PCI devices.

ok show-pci-devs-all (show all pci devices)

Use the show-pci-config command to show configuration space registers for a given PCI device.

ok show-pci-config /pci@1f,4000/network@1,1

Use the show-pci-configs command to show configuration space registers for all PCI devices on a PCI bus.

ok show-pci-configs /pci@1f,4000

Use the show-pci-configs-all command to show configuration space registers for all PCI devices on all PCI busses.

ok show-pci-configs-all /pci@1f,4000

Use the probe-pci command to probe all devices on a specific PCI bus.

ok probe-pci /pci@1f,4000

probing /pci@1f,4000 at Device 3 scsi disk tape

probing /pci@1f,4000 at Device 3 nothing there

Use the probe-pci-slot command to probe a specific PCI slot on a specific PCI bus.

ok 3 probe-pci-slot /pci@1f,4000

probing /pci@1f,4000 at Device 3 scsi disk tape

Updating OpenBoot PROM for Sun Workstations and Workgroup Servers ...

Having the latest version of OpenBoot PROM (OBP) on a SPARC processor-based workstation or workgroup server can be critical when adding new applications or hardware, or when upgrading the machine's Solaris Operating System (OS). Updating may also save some time and difficulty by resolving any latent bugs that have been detected and fixed since the previous releases. The paragraphs that follow guide you through the steps required to do the update.

Note: This Tech Tip does not cover larger servers; for those systems, see SunSolve document #41723

How to Perform System Boot and Shutdown Procedures for Solaris 10 ...

[PDF] Debugging Solaris using Open Boot Prom

Solaris 9 System Startup and Shutdown > The OpenBoot Architecture

OpenBoot > OpenBoot Environment

Open Boot Parameters Adminschoice.com

The firmware in Sun's boot PROM is called OpenBoot. The main features of openboot are initial program loading, & debugging features to assist kernel debugging .OpenBoot supports plug-in device drivers which are written in language Forth. . This plug in feature allows Sun or any third-party vendors to develop new boot devices but without making any changes to boot PROM.

See also Solaris Booting problems error messages & solutions

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OpenBoot > OpenBoot Environment

Sun's "OpenBoot 3.x Command Reference Manual", Chapter 1. (Used to be at http://docs.sun.com/db/doc/805-4436/6j4719c8a?a=view).

Solaris 9 System Startup and Shutdown

Objectives

The following objectives for the Solaris System Administrator Exam are covered in this chapter:

Explain how to execute boot PROM commands to

• Identify the system's boot PROM version
• Boot the system; access detailed information
• List, change, and restore default NVRAM parameters
• Display devices connected to the bus
• Identify the system's boot device
• Create and remove custom device aliases
• View and change NVRAM parameters from the shell
• Interrupt a hung system
• Given a scenario involving a hung system, troubleshoot problems and deduce resolutions.
• Explain how to perform a system boot, control boot processes, and complete a system shutdown, using associated directories, scripts, and commands.

You need to understand the primary functions of the OpenBoot environment, which includes the programmable read-only memory (PROM. You need to have a complete understanding of how to use many of the OpenBoot commands and how to set and modify all the configuration parameters that control system bootup and hardware behavior.

You must understand the entire boot process, from the proper power-on sequence to the steps you perform to bring the system into multiuser mode.

You must be able to identify the devices connected to a system and recognize the various special files for each device.

Occasionally, conventional shutdown methods might not work on an unresponsive system or on a system that has crashed. This chapter introduces when and how to use these alternative shutdown methods to bring the system down safely.

You must understand how the system run levels define which processes and services are started at various stages of the boot process. You need to understand all the run levels that are available in Solaris.

You need to understand how to add and modify run control scripts to customize the startup of processes and services on Solaris systems. You need to have a detailed understanding of the programs and configuration files involved at the various run levels.

Outline

Introduction

Booting a System

• Powering On the System
• The Boot PROM and Program Phases

The OpenBoot Environment

• Entry-Level to High-End Systems
• Accessing the OpenBoot Environment
• OpenBoot Firmware Tasks

The OpenBoot Architecture

The OpenBoot Interface

• The Restricted Monitor
• The Forth Monitor

Getting Help in OpenBoot

PROM Device Tree (Full Device Pathnames)

• OpenBoot Device Aliases

OpenBoot NVRAM

• The nvedit Line Editor

OpenBoot Security

OpenBoot Diagnostics

• Input and Output Control

OpenBoot PROM Versions

Booting a System

• The boot Command

The Kernel

System Run States

• swapper
• The init Phase
• rc Scripts
• Using the Run Control Scripts to Stop or Start Services
  • Adding Scripts to the Run Control Directories

System Shutdown

• Commands to Shut Down the System
  • The /usr/sbin/shutdown Command
  • The /sbin/init Command
  • The /usr/sbin/halt Command
  • The /usr/sbin/reboot Command
  • The /usr/sbin/poweroff Command

Stopping the System for Recovery Purposes

Turning Off the Power to the Hardware

Summary

Apply Your Knowledge

Study Strategies

The following study strategies will help you prepare for the exam:

• When studying this chapter, you should practice on a Sun system each step-by-step process that is outlined. In addition to practicing the processes, you should practice the various options described for booting the system.
• You should display the hardware configuration of your Sun system by using the various OpenBoot commands presented in this chapter. You need to familiarize yourself with all the devices associated with your system. You should be able to identify each hardware component by its device pathname.
• You should practice creating both temporary and permanent device aliases. In addition, you should practice setting the various OpenBoot system parameters that are described in this chapter.
• You should practice booting the system by using the various methods described. You need to understand how to boot into single-user and multiuser modes and how to specify an alternate kernel or system file during the boot process.
• During the boot process, you should watch the system messages and familiarize yourself with every stage of the boot process. You should watch the system messages that are displayed at bootup. You need to understand each message displayed during the boot process from system power-on to bringing the system into multiuser mode.
• You need to thoroughly understand all the system run states, including when and where to use each of them. In addition, you must understand run control scripts and how they affect the system services. You should practice adding your own run control scripts.
• You should practice shutting down the system. You should make sure you understand the advantages and disadvantages of each method presented.

Introduction

System startup requires an understanding of the hardware and the operating system functions that are required to bring the system to a running state. This chapter discusses the operations that the system must perform from the time you power on the system until you receive a system logon prompt. In addition, it covers the steps required to properly shut down a system. After reading this chapter, you'll understand how to boot the system from the OpenBoot programmable read-only memory (PROM) and what operations must take place to start up the kernel and Unix system processes.

Plagiarism?By David, Feb 3, 2004 05:11 PM

Much of this seems to be copied, with minor modification, from Sun's "OpenBoot 3.x Command Reference Manual", Chapter 1. (Currently at http://docs.sun.com/db/doc/805-4436/6j4719c8a?a=view).

For example, the Sun documentation says: "OpenBoot deals directly with hardware devices in the system. Each device has a unique name representing the type of device and where that device is located in the system addressing structure."

In the this article, it's been changed slightly to read: "OpenBoot deals directly with the hardware devices in the system. Each device has a unique name that represents both the type of device and the location of that device in the device tree."

Sometimes, the minor changes alter the meaning. For example, the Sun doc says: "A full device path name is a series of node names separated by slashes (/). The root of the tree is the machine node, which is not named explicitly but is indicated by a leading slash (/). Each node name has the form:

driver-name@unit-address:device-arguments"

In the copied version posted here, though, it's: "A device tree is a series of node names separated by slashes (/).The top of the device tree is the root device node. Following the root device node, and separated by a leading slash /, is a bus nexus node. Connected to a bus nexus node is a leaf node, which is typically a controller for the attached device. Each device pathname has this form:

driver-name@unit-address:device-arguments"

The first sentence is incorrect, and the last sentence is confusing. It's each nodename that has that form, not the pathname, which is a series of slash delimited nodenames.

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