3.6. Setting Options

ABLE has the ability to store settings which remain after reset or power cycle and are hence referred to as non-volatile. This feature is available on all systems, however the amount of storage may vary which will limit the maximum lengths of some parameters such as the default boot command.

The settings are presented as non-volatile variables which can be simply assigned. However these settings will not be made permanent until a nvsave command is issued.

The variables are numbers, strings or boolean values. The nvshow command can be used without arguments in order to list the current values of all variables.

Example 3.3. Using the nvshow command to list the default variables

shell.hist (is unset)
boot.fs (is unset)
boot.auto  = off
boot.cmd (is unset)
boot.timeout (is unset)
ide.multi-limit (is unset)
usb.hubdepth (is unset)
usb.enable (is unset)
console.level  = 9
console.write (is unset)
console.read (is unset)
fb.enable (is unset)
fb.output (is unset)
fb.refresh (is unset)
fb.y (is unset)
fb.x (is unset)
sys.autoshadow (is unset)
sys.speed (is unset)

Section 4.2.2, “Non volatile variables” fully explains the use of these variables and the alternative commands for manipulating them. Appendix A, Non-Volatile Variables Reference is a list of variables, their meanings and default values.

Values altered by assignment or the nvset command are not permanent until the nvsave command has been issued. The nvsave command commits the current changes to the non volatile storage, without this the changes will be lost upon a system reset.

The nvclear command can be used to restore the values back to the defaults. The nvsave should not be used to attempt to save these values, this would result in the current settings state being saved not the default values.