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Unit 2 – The Boot Unit 2 – The Boot Prom – OpenBootProm – OpenBoot

Randy Marchany

VA Tech Computing Center

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Introduction

OpenBoot is the firmware that controls the boot process of a Sun workstation.

It contains diagnostic commands that can help you determine HW configurations.

It is similar to the PC-BIOS of Intel platforms.

OpenBoot controls the monitor. It has no printscreen capability.

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OpenBoot

OpenBoot commands can be entered directly from the system console or from a serial terminal connected to the TTYA or TTYB port on a Sparc workstation.

Press STOP-A to get in OpenBoot mode if using the monitor.

Press BREAK (CTRL-]) then ‘send break’ if connected through a telnet session.

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OpenBoot

Initial output is a banner that describes the type of SPARC processor, OpenBoot version, memory size, Ethernet address.

Can be set up to boot automatically or wait for additional commands– type b (boot), c (continue) or n (new command mode)

– b, c options go to Restricted Monitor mode– N selects full OpenBoot mode, prompt goes from > to

OK.– Use the help command to get a full list of commands

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OpenBoot Keyboard Commands

Action Effect

STOP-A Abort the system

STOP Bypass POST

STOP-D Enter diagnostic mode

STOP-N Reset NVRAM to defaults

Go Resume operation

Sync Synchronize disk data

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OpenBoot – Device Aliases

Sun hardware names are mysterious at best. You can create aliases for these device names. Common commands

– .attributes – list device attributes– .properties – newer version of .attributes– cd – change directory– printenv – displays environment variables– setenv – set the environment variables– show-disks – list disk devices attached to system

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OpenBoot

The “auto-boot?” environment variable tells OpenBoot to automatically boot the system after any failure if it’s set to TRUE.

Otherwise, the system will remain at the OK prompt until you manually enter the boot command.

OpenBoot builds a map of all devices connects to the system during boot. This is called a device tree.

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OpenBoot Device Trees

The device tree describes all elements of the computer configuration.

Properties: characteristics of the device like its address

Methods: the commands you can issue that involve the device

Self-test: example of a method Children/parent: describes the HW unit above

and below the device

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OpenBoot Device Tree

Top of the tree is the SPARC processor. Next level: HW devices present on the

motherboard – memory, bus (sbus or PCI), serial ports, keyboard, mouse, etc.

Next level: controller card attached to the bus (SCSI or PCI). The bus can have multiple controllers

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OpenBoot Device Tree

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OpenBoot Device Tree

/sbus@1f,0/esp@0,40000/sd@3,0:a /sbus@1f,0 - the Sbus address /esp@0,40000 - the external controller

address /sd@3,0:a - the unit attached to the

controller Labels, sd, sd0, sd1 are usually SCSI disks. Use an alias instead of this long name.

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OpenBoot Device Aliases

nvalias command creates a device alias.– Syntax: nvalias alias-name real-device-name– Example: nvalias bigdisk

/pci@1f,0/pci@1,1/ide@3/cdrom@2,0:f

List all aliases with the .properties command devalias command does the same thing but it’s

temporary. Stays in effect until the next reset. Nvalias is the permanent command.