Unit 2 – The Boot
Prom – 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
Go
Reset NVRAM to
defaults
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
–
–
–
–
–
–
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.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.
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