Open Boot

Open Boot is the boot loader progran for Sparcs


format: name@address,arguements

e.g. /sbus@1,f8000000/esp@0,40000/sd@3,0:a

This means disk partition a on scsi disk at target 3, logical unit 0 on the esp device at slot 0, offset 40000 which is connected to sbus (system bus) at slot 1 offset f8000000

Device Aliases

To save having to type full device paths, aliases can be used. For the most common devices these are already defined, e.g.cdrom. The command devalias is used to define aliases.

Note: Aliases defined by devalias are temporary and are lost after a power cycle or system reset. Use nvalias to create alias permanent (see below).

Device trees can be shown with Unix like commands e.g. ls, pwd, cd .show-devs shows all devices from the current level down.


format: boot device-specifier filename options


Nonvolatile RAM

NVRAM contains the system configuration parameters which control machine start up configuration and communications characteristics

Security Parameters

Access to the open boot commands can be limited using the security parameters. i.e. setting security-mode to none , command or full . command mode requires a password for some functions, full is also known as restricted mode and requires a password for most functions. It also enables restricted monitor format, i.e. a menu.


This is a portion of nvram reserved for user commands.

Changing NVRAMRC contents