Introduction to the Boot Process - System Startup and Shutdown Chapter Syllabus

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Chapter 14. System Startup and Shutdown Chapter Syllabus

14.1 Introduction to the Boot Process

14.2 Processor Dependent Code 14.3 Boot Area on the System Disk 14.4 Initial System Loader

14.5 Loading the HP-UX Kernel 14.6 The init Process

14.7 Runlevels

14.8 Adding a Program to Run at Boot Time 14.9 System Shutdown

Understanding of the system startup and shutdown processes is very important both for routine system administration and troubleshooting. Every HP-9000 server or workstation is supplied with boot code that resides on ROM. As soon as you power on the system, this code executes and performs self-tests and some initialization tasks. It then loads the HP-UX kernel and hands control over to it. The kernel does a number of system initialization tasks before you get a login prompt on your console or terminal. This chapter covers in detail all of the processes that take place from system power on to the display of the login prompt.

In the beginning, you will see an overview of the boot process. The boot process starts from processor dependent code (PDC) that resides on ROM in your system. You will learn how to work with PDC and use its commands by interrupting the boot process. During the boot process, the PDC checks for boot area on the primary boot disk. You will learn the structure of the boot area to build an understanding of this part of the boot disk. The initial system loader (ISL) is used to load the kernel into memory. Its knowledge is important if you need to boot your machine in single-user mode. You have to rebuild the HP-UX kernel many times, and ISL helps you boot from an old kernel if your new kernel is misconfigured and fails to boot. You will also see how the autoboot works and how to enable or disable it.

Once the HP-UX kernel is loaded into memory, it initializes other processes. The init process is the most important of all of these. It is responsible for most of the system initialization. When you study the section containing information about the init process, you will see the structure of its configuration file and how it performs automatic initialization of other processes at different stages of the boot process. Runlevels show the system state at a particular instant, and these are also controlled by the init process. You will see which runlevels are supported on HP-UX and what the function is of each. Changing system states by changing runlevels is also explained at this stage.

Many times you need to perform a task right after the system boots up. You may also need to run a program at the boot time. You will find a complete example of how programs are started and stopped during the system startup and shutdown processes. In the last part of this chapter, the shutdown process will be presented. You will see the difference between the shutdown and reboot commands. After going through this chapter, you will understand the startup and shutdown processes and the different stages that involve these processes. In addition, you will have knowledge of commands and utilities that are used for this purpose. Having a good understanding of this process, you will be able to troubleshoot any HP-UX startup or shutdown problem.

14.1 Introduction to the Boot Process

The boot process of an HP-9000 server or workstation starts when you power it on or when you reboot a running system. It can be divided into two main parts.

• boot ROM startup • HP-UX startup

In the first stage, the boot ROM startup process is carried out. At its completion, it initiates the HP-UX startup process, which is completed in a number of steps. On an abstract level, the boot sequence can be divided into the following steps.

Power on or reboot.

The processor dependent code (PDC) executes and performs self-tests. These tests include memory and CPU tests. The PDC also detects any peripherals attached to the system. PDC initializes the console to display messages. It looks for the primary boot path for booting the system. The boot path

is the hardware path to the disk used as the boot device.PDC loads and executes the initial system loader (ISL) from the boot path and executes it. At this stage in the startup process, the role of the boot ROM ends. ISL loads the secondary system loader known as hpux, which resides on the boot area of the disk. The hpux loads the HP-UX kernel /stand/vmunix into memory and hands control over to the kernel.

The kernel starts the swapper process and then the init process.

The init process reads its initialization file, /etc/inittab, and initializes most of the operating system daemons and processes. It brings the system into an appropriate state and makes it usable for users.

As soon as the init process has completed its tasks, you see a login prompt at the console or at any terminal attached to the system. Part of a sample boot process is shown here.

Primary boot path = 0/2/0.6.0 Alternate boot path = 7/2/0.6.0 Console path = 15/1 Keyboard path = 15/1

[*** Manufacturing (or Debug) Permissions ON ***] System is HP9000/800/V2500 series

Processor is starting the autoboot process. To discontinue, press any key within 10 seconds. Device : 0/2/0.6.0

File : hpux Arguments : hpux

Loading : hpux ... 163808 bytes loaded. 102368 + 61440 + 864504 start 0xd01cc0 Boot : disc(0/2/0.6.0;0)/stand/vmunix 6848512 + 1181408 + 6521760 start 0x3a168 5/2/0.8.0.255.1.2.0 sctl Probing epic6

Probe of epic6 complete 6 saga

6/0/0 btlan6 6/1/0 fcT1 6/1/0.5 fcT1_cntl 6/1/0.8 fcp

System Console is on SPP DUART0 Interface WARNING: max message size > 65535, adjusting. WARNING: max bytes on msg q > 65535, adjusting. Logical volume 64, 0x3 configured as ROOT Logical volume 64, 0x2 configured as SWAP Logical volume 64, 0x2 configured as DUMP

Swap device table: (start & size given in 512-byte blocks) entry 0 - major is 64, minor is 0x2; start = 0, size = 2097152 Starting the STREAMS daemons-phase 1

Checking root file system.

file system is clean - log replay is not required Root check done.

Create STCP device files Memory Information:

physical page size = 4096 bytes, logical page size = 4096 bytes Physical: 16773120 Kbytes, lockable: 12203164 Kbytes, available: 14014856 Kbytes

/sbin/ioinitrc:

Starting /sbin/ioscan -f 1> /dev/null Starting /sbin/insf -e -C disk 1> /dev/null Done ioscan & insf

/sbin/bcheckrc:

Checking for LVM volume groups and Activating (if any exist) Volume group "/dev/vg00" has been successfully changed. Resynchronized volume group /dev/vg00

vxfs fsck: sanity check: root file system OK (mounted read/write) (c)Copyright 1983-1997 Hewlett-Packard Co., All Rights Reserved. (c)Copyright 1979, 1980, 1983, 1985-1993 The Regents of the Univ. of California

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/sbin/auto_parms: DHCP access is disabled (see /etc/auto_parms.log) HP-UX Start-up in progress

__________________________

Configure system crash dumps ... OK Mount file systems ... OK

Update kernel and loadable modules ... N/A Initialize loadable modules ... N/A Setting hostname ... OK Set privilege group ... N/A Display date ... N/A

Save system crash dump if needed ... N/A Enable auxiliary swap space ... OK Start syncer daemon ... OK Configure HP Fibre Channel interfaces ... OK ... OK

Configure Loopback interfaces (lo0) ... OK Start Software Distributor agent daemon ... OK Configuring all unconfigured software filesets ... OK Recover editor crash files ... OK Clean UUCP ... OK List and/or clear temporary files ... OK

Clean up old log files ... OK

Start system message logging daemon ... OK Start pty allocator daemon ... OK Start network tracing and logging daemon ... OK Configure HP Ethernet interfaces ... OK Configure HP 100BT interfaces ... OK Configure HP SPP 100BT interfaces ... OK Configure LAN interfaces ... OK Start name server daemon ... N/A Start NFS core subsystem ... OK Start NIS+ server subsystem ... OK Start NIS+ client subsystem ... OK Start NIS server subsystem ... OK Start NIS client subsystem ... OK Start NFS client subsystem ... OK Start the Trusted Mode with Nis+ subsystem ... N/A Configure pseudo devices for MAC/LLA access ... OK Start multicast routing daemon ... N/A Start Internet services daemon ... OK Start dynamic routing daemon ... N/A Start router discover protocol daemon ... N/A Configuring PPP Interface ... OK Start RARP protocol daemon ... N/A Start remote system status daemon ... N/A Configuring man pages for Internet Services ... OK Starting mail daemon ... OK

Starting outbound connection daemons for DDFA software .... N/A Start SNMP Master Network Management daemon ... OK Start OSPF MIB Network Management subAgent ... N/A Start SNMP HP-UNIX Network Management subAgent ... OK Start SNMP MIB-2 Network Management subAgent ... OK Start SNMP Trap Dest Network Management subAgent ... OK Start DCE daemons ... N/A

Start RPC daemon if needed ... OK Start the Isogon License Server daemon ... N/A Start remote boot daemon ... OK Starting X Font Server at TCP port 7000 ... N/A Start vt daemon ... OK

Start time synchronization ... OK Start accounting ... OK

Starting the password/group assist subsystem ... OK Starting disk array monitor daemons. ... OK Start print spooler ... OK

Starting HP Distributed Print Service ... OK Start clock daemon ... OK Support Tools Informational Fileset ... OK Start diagnostic subsystem ... OK Starting hardware predictive ... OK Start environment monitoring daemon ... OK Start auditing subsystem ... N/A Start audio server daemon ... N/A SAM System administration configuration ... OK MeasureWare performance software is being started. ... OK Reinitialize Software Distributor agent daemon ... OK Starting Event Monitoring Service ... OK Start EMS SNMP subagent ... OK Start NFS server subsystem ... OK Start X print server(s) ... N/A Start CDE login server ... OK

The system is ready.

GenericSysName [HP Release B.11.00] (see /etc/issue) Console Login:

In the next sections, you will learn more details on how these tasks are performed. 14.2 Processor Dependent Code

The boot procedure for all HP-9000 systems is controlled by program code, PDC, that resides on the ROM installed inside the system. The PDC is different for different computers (that is why its name is processor dependent). PDC is executed after the system is reset or turned on. It performs self-tests and then tests hardware attached to the system. After thoroughly scanning the memory, it initializes the console and copies the console path to the memory. It copies the boot path and autoboot flag into memory. If the autoboot is disabled, it displays a menu of commands. If the autoboot is enabled, it displays a message showing that the system is going to start the autoboot process and gives you the option to interrupt this process by pressing a key within 10 seconds. If you press a key within 10 seconds, you get the PDC menu; otherwise, the system starts booting from the primary boot path. PDC is an important part, where you perform system administration tasks to specify primary and alternate boot devices. You can display hardware paths and search boot devices attached to the system. You can also use PDC to boot the system from a device other than primary or secondary boot devices. On V-Class machines, PDC can also be used to boot into single-user mode.

PDC Menus

You get PDC menus by interrupting the boot process by pressing a key when a message like the following is displayed.

Processor is starting the autoboot process. To discontinue, press any key within 10 seconds.

PDC menus may differ on servers and workstations slightly, but most of the commands are the same on all systems. A typical PDC menu looks likes the following.

--- Main Menu --- Command Description

--- ---

BOot [PRI|ALT|<path>] Boot from specified path PAth [PRI|ALT|<path>] Display or modify a path SEArch [Display|IPL] [<path>] Search for boot device COnfiguration menu Displays or sets boot values INformation menu Displays hardware information SERvice menu Displays service commands

Help [<menu>|<command>] Displays help for menu or cmd RESET Restart the system

---

Main Menu: Enter command or menu >

You can use any of these commands; most of the arguments are optional. For example, using the boot command without any arguments will start the autoboot process. If you want to boot from the alternate boot device, you can use the boot alt command. In case you need to boot the system from a device that is neither a primary nor an alternate boot device (such as booting from CD-ROM when installing HP-UX), you can specify the device name as an argument to the boot command.

All of these commands can be abbreviated. The capital letters in the start of each command show the command abbreviation. For example, you can use "bo" instead of boot and "sea" instead of the search command. Help on commands is also available with the Help command.

Searching Boot Devices

You need to search for boot devices if you don't know the exact name of a device for boot purposes. This is often required when installing a new system. The search command shows all disk drives, CD- ROM devices, and tape drives attached to the system. Output of the search command is like the one given here.

Main Menu: Enter command or menu > search Searching for potential boot device(s)

This may take several minutes. To discontinue search, press any key

Path Number Device Path (dec) Device Type --- --- ---

P0 10/0/6 Random Access Media P1 10/0/5 Random Access Media P2 10/0/4 Random Access Media P3 10/0/3 Random Access Media P4 10/0/2 Random Access Media P5 10/0/1 Random Access Media P6 10/4/4.2 Toshiba CD-ROM Device P7 10/4/4.1 Sequential Access Media

Random Access Media shows disks attached to the system, and Sequential Access Media is for tape drives. You can also see a line for a CD-ROM drive. Sometimes you will see Random Access Media in place of the CD-ROM drive. In that case, you have to make a guess which device shows the CD-ROM if you are not familiar with your HP system hardware configuration.

To boot from a particular device, you can use its path number or device path. For example, to boot from a CD-ROM, you can use any of the boot P6 or boot 10/4/4.2 commands.

Booting from an Alternate Disk

Many people use mirrored disks in servers for redundancy and reliability. In a mirror disk configuration, two disks have exactly the same data. Boot devices can also be mirrored so that in case one disk fails to boot the system, it may use the alternate one for the boot process.

To configure an alternate boot device, you can use the configure command. To manually boot from the alternate disk device, use the boot alt command.

Stable Storage

Stable storage is nonvolatile memory where your system stores information about the following. • primary boot path

• alternate boot path • console

• autoboot • autosearch

This information is used by PDC. You can change this information using the configure command. Autoboot and autosearch are either on or off.

Booting in Single-User Mode

On V-Class machines, you can use PDC to boot the system in single-user mode for maintenance purposes. The PDC command used for this purpose is:

Main Menu: Enter command or menu > boot pri -is

On other machines, you can stop the boot process and use ISL to boot into single-user mode as shown here.

Main Menu: Enter command or menu > boot pri Interact with ISL (Y or N)?> Y

When you get the ISL prompt, use the following command to boot into single-user mode. ISL> hpux -is

In document Rehman_HP (Page 165-170)