The Command Monitor Environment

The Command Monitor Environment

The Command Monitor maintains an environment, which is a list of variable names and corresponding values (the values are actually text strings). These environment variables contain information that the Command Monitor either uses itself or passes to booted programs. The system stores some environment variables--those that are important and unlikely to change frequently--in non-volatile RAM (nvram). If you turn off power to the machine or press the Reset button, the system remembers these variables. When you change the setting of these variables using the setenv command, the PROM code automatically stores the new values in non-volatile RAM.

You can also use the /etc/nvram command to set or print the values of non-volatile RAM variables on your system. For complete information on the nvram command, see the nvram(1) reference page.

Table 10-5, " Variables Stored in Non-volatile RAM," shows a list of the environment variables that the system stores in non-volatile RAM.

The ARCS Prom defines some variables not found in older PROMS, and so an additional list is provided in Table 10-7.

Several environment variables also exist that affect IRIX's operation. These are not stored in non-volatile RAM, but they do affect the operation of the PROM and of IRIX. See Table 10-6.

Table 10-5 lists non-volatile RAM variables:

Variables Stored in Non-volatile RAM
Variable Description
netaddr Specifies the local network address for booting across the Ethernet. See the bootp protocol.
dbaud Specifies the diagnostics console baud rate. You can change it by setting this variable (acceptable rates include 75, 110, 134, 150, 300, 600, 1200, 2400, 4800, 9600, and 19200), or by pressing the <Break> key. IRIS uses the dbaud rate for the diagnostics console during the entire system start-up. Pressing the <Break> key changes the baud rate only temporarily; the baud rate reverts to the value specified in dbaud or rbaud when you press the reset switch or issue an init command.
rbaud Specifies the remote console baud rate. The list of acceptable baud rates is the same as for dbaud, above.
bootfile Specifies the name of the file to use for autobooting, normally a stand-alone shell (sash). This variable is valid for pre-ARCS PROMs only. ARCS proms store this information in the OSLoader variable.
bootmode Specifies the type of boot in pre-ARCS PROMs. ARCS PROMs store this information in the AutoLoad variable.
The options have these meanings:
c - performs a complete cold autoboot, using the file pointed to by the bootfile variable to boot the kernel; boots sash, then boots kernel; runs power-on diagnostics.
m - (default) goes straight to the Command Monitor; clears memory; runs power-on diagnostics.
d - go straight to the Command Monitor; do not clear memory; do not run power-on diagnostics (on IRIS-4D 100, 200 and 300 series systems, this has the same effect as bootmode m).
boottune Selects the boot music string. A value of 0 randomizes the selection each time. 1 is the default value. (Supported only on Power Indigo2)
autopower Allows systems with software power control to automatically reset after a power failure if set to y.
console Specifies which console to use. The options have these meanings:
G - graphics console with the Silicon Graphics, Inc., logo in the upper left corner
g - (default) graphics console without the Silicon Graphics logo
keybd Specifies the type of keyboard used. The default is ''df.'' Available settings depend on the exact PROM revision, but may include some or all of:
USA, DEU, FRA, ITA, DNK, ESP, CHE-D, SWE, FIN, GBR, BEL, NOR, PRT, CHE-F.
or
US, DE, FR, IT, DK, ES, deCH, SE, FI, GB, BE, NO, PT, frCH on systems with the keyboard layout selector.
On some systems, JP is also acceptable to specify a Japanese keyboard.
diskless Specifies that the system is diskless and must be booted over the network. On ARCS systems, diskless system environment parameters should be set as follows:
diskless=1
SystemPartition=bootp()host:/path
OSLoader=kernelname
monitor Specifies the monitor resolution on Indy systems when an unrecognized brand of monitor is used. Set this variable to h or H to specify a high resolution monitor, the default is a low resolution monitor.
nogfxkeybd Specifies that the keyboard is not required to be connected if set to 1.
notape Specifies that no tape drive is attached to the system. If a tape drive is attached to the system, this variable must be set to 1 (true) in order to access a tape drive on another system on the network.
volume Specifies the system speaker volume numerically.
pagecolor Specifies the background color of the textport using a set of 6 hexadecimal RGB values.
prompoweroff On Indy systems only, this variable specifies that the system should return to the PROM monitor before powering down on shutdown if set to y.
rebound Specifies that the system should automatically reboot after a kernel panic if set to y.
sgilogo Specifies that the Silicon Graphics logo and related information will be displayed on the PROM monitor graphical screen if set to y.
diagmode Specifies the mode of power-on diagnostics. If set to v, then diagnostics are verbose and extensive. .

Variables Stored in Non-volatile RAM
Variable	Description
netaddr	Specifies the local network address for booting across the Ethernet. See the bootp protocol.
dbaud	Specifies the diagnostics console baud rate. You can change it by setting this variable (acceptable rates include 75, 110, 134, 150, 300, 600, 1200, 2400, 4800, 9600, and 19200), or by pressing the <Break> key. IRIS uses the dbaud rate for the diagnostics console during the entire system start-up. Pressing the <Break> key changes the baud rate only temporarily; the baud rate reverts to the value specified in dbaud or rbaud when you press the reset switch or issue an init command.
rbaud	Specifies the remote console baud rate. The list of acceptable baud rates is the same as for dbaud, above.
bootfile	Specifies the name of the file to use for autobooting, normally a stand-alone shell (sash). This variable is valid for pre-ARCS PROMs only. ARCS proms store this information in the OSLoader variable.
bootmode	Specifies the type of boot in pre-ARCS PROMs. ARCS PROMs store this information in the AutoLoad variable. The options have these meanings: c - performs a complete cold autoboot, using the file pointed to by the bootfile variable to boot the kernel; boots sash, then boots kernel; runs power-on diagnostics. m - (default) goes straight to the Command Monitor; clears memory; runs power-on diagnostics. d - go straight to the Command Monitor; do not clear memory; do not run power-on diagnostics (on IRIS-4D 100, 200 and 300 series systems, this has the same effect as bootmode m).
boottune	Selects the boot music string. A value of 0 randomizes the selection each time. 1 is the default value. (Supported only on Power Indigo2)
autopower	Allows systems with software power control to automatically reset after a power failure if set to y.
console	Specifies which console to use. The options have these meanings: G - graphics console with the Silicon Graphics, Inc., logo in the upper left corner g - (default) graphics console without the Silicon Graphics logo
keybd	Specifies the type of keyboard used. The default is ''df.'' Available settings depend on the exact PROM revision, but may include some or all of: USA, DEU, FRA, ITA, DNK, ESP, CHE-D, SWE, FIN, GBR, BEL, NOR, PRT, CHE-F. or US, DE, FR, IT, DK, ES, deCH, SE, FI, GB, BE, NO, PT, frCH on systems with the keyboard layout selector. On some systems, JP is also acceptable to specify a Japanese keyboard.
diskless	Specifies that the system is diskless and must be booted over the network. On ARCS systems, diskless system environment parameters should be set as follows: diskless=1 SystemPartition=bootp()host:/path OSLoader=kernelname
monitor	Specifies the monitor resolution on Indy systems when an unrecognized brand of monitor is used. Set this variable to h or H to specify a high resolution monitor, the default is a low resolution monitor.
nogfxkeybd	Specifies that the keyboard is not required to be connected if set to 1.
notape	Specifies that no tape drive is attached to the system. If a tape drive is attached to the system, this variable must be set to 1 (true) in order to access a tape drive on another system on the network.
volume	Specifies the system speaker volume numerically.
pagecolor	Specifies the background color of the textport using a set of 6 hexadecimal RGB values.
prompoweroff	On Indy systems only, this variable specifies that the system should return to the PROM monitor before powering down on shutdown if set to y.
rebound	Specifies that the system should automatically reboot after a kernel panic if set to y.
sgilogo	Specifies that the Silicon Graphics logo and related information will be displayed on the PROM monitor graphical screen if set to y.
diagmode	Specifies the mode of power-on diagnostics. If set to v, then diagnostics are verbose and extensive. .

Table 10-6 lists Command Monitor environment variables that directly affect the operating system. Note that these variables are not stored in non-volatile RAM and are discarded if the machine is powered down.

Environment Variables That Affect the IRIX Operating System
Variable Description
showconfig Prints extra information as IRIX boots. If set through setenv, its value must be istrue.
initstate Passed to IRIX, where it overrides the initdefault line in /etc/inittab. Permitted values are s and the numbers 0-6. See init(1M).
swap Specifies in IRIX notation the swap partition to use. If not set, it defaults to the partition configured into the operating system, which is normally partition 1 on the drive specified by the root environment variable.
path Specifies a list of device prefixes that tell the Command Monitor where to look for a file, if no device is specified.
verbose Tells the system to display detailed error messages.

Environment Variables That Affect the IRIX Operating System
Variable	Description
showconfig	Prints extra information as IRIX boots. If set through setenv, its value must be istrue.
initstate	Passed to IRIX, where it overrides the initdefault line in /etc/inittab. Permitted values are s and the numbers 0-6. See init(1M).
swap	Specifies in IRIX notation the swap partition to use. If not set, it defaults to the partition configured into the operating system, which is normally partition 1 on the drive specified by the root environment variable.
path	Specifies a list of device prefixes that tell the Command Monitor where to look for a file, if no device is specified.
verbose	Tells the system to display detailed error messages.

When you boot a program from the Command Monitor, it passes the current settings of all the environment variables to the booted program.

The environment variables specific to ARCS Proms are described in Table 10-7.

ARCS PROM Environment Variables
Variable Description
ConsoleIn/ConsoleOut These variables are set automatically at system startup.
OSLoadPartition The disk partition where the operating system kernel is located. This is also used as the default root partition and is set automatically at system startup.
OSLoader The operating system loading program. By default, this is SASH (The Stand-Alone Shell). This is set automatically at system startup.
SystemPartition The disk partition where the operating system loading program is found. This is set automatically at system startup.
OSLoadFilename The file name of the operating system kernel. By default, this is /unix. This variable is automatically set at system startup.
OSLoadOptions This variable specifies options to the boot command used to load the Operating System. For more information on boot options, see "Booting a Program from the Command Monitor".
AutoLoad This variable specifies whether the operating system will boot automatically after a reset or power cycle. This variable supercedes bootmode and can be set to yes or no.

ARCS PROM Environment Variables
Variable	Description
ConsoleIn/ConsoleOut	These variables are set automatically at system startup.
OSLoadPartition	The disk partition where the operating system kernel is located. This is also used as the default root partition and is set automatically at system startup.
OSLoader	The operating system loading program. By default, this is SASH (The Stand-Alone Shell). This is set automatically at system startup.
SystemPartition	The disk partition where the operating system loading program is found. This is set automatically at system startup.
OSLoadFilename	The file name of the operating system kernel. By default, this is /unix. This variable is automatically set at system startup.
OSLoadOptions	This variable specifies options to the boot command used to load the Operating System. For more information on boot options, see "Booting a Program from the Command Monitor".
AutoLoad	This variable specifies whether the operating system will boot automatically after a reset or power cycle. This variable supercedes bootmode and can be set to yes or no.

Displaying the Current Environment Variables
Changing Environment Variables
Setting the Keyboard Variable
Removing Environment Variables