CLI Basics part 4

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CMOS RAM

Many configuration settings are held in CMOS RAM. On some systems this is a reserved area of nonvolatile memory; on the Raspberry Pi it is a file that is loaded from the SD card during system boot.

Not all of the settings held in CMOS RAM can be changed from the RISC OS Desktop, and there are occasions (e.g. failure of an SD card) where the desktop cannot be reached.

Many of the potential problems can be avoided by keeping a backup copy of CMOS RAM contents somewhere else. Two star commands will assist in this endeavour:

*SaveCMOS

Saves the current contents of CMOS RAM to a named file. It is a good idea to keep this copy somewhere safe (e.g. on an external disc drive) so that it will be available for use in an emergency. For example:
*SaveCMOS SCSI::5.$.Backup.CMOS-copy

*LoadCMOS

Loads a previously-saved CMOS file into CMOS RAM. The file will be rejected if it is the wrong size, if the checksum is incorrect, or if it was saved using a different version of RISC OS.
*LoadCMOS SCSI::5.$.Backup.CMOS-copy

*Status

The *Status command displays the current settings of all configuration options that can be adjusted by *Configure. The list is quite long, so if you’re not using a task window you may need to press SHIFT to page through to the end.

Individual settings can be queried by specifying the desired item. For example:
*Status filesystem
may produce the result
FileSystem SDFS

*Configure

There are occasions (e.g. when setting up a new machine for the first time) when adjusting individual CMOS settings from the command line is unavoidable. The *Configure command allows you to do this.

Useful *Configure commands

There are many other *Configure commands available – see *Configure for a full list. In most cases it is easier to set the remaining options from the desktop rather than from the command line. They could still be useful if, for example, you wanted to automate the setup of a machine by placing all of the *Configure commands into an Obey file.

Further reading

• *Configure – contains a full list of all *Configure commands

The “StarComms” file – which can be found in $.Documents.UserGuide in the standard RISC OS HardDisc4 image – also contains a list of *Configure commands.

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