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cmos [2010/04/15 21:18] (current)
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 +===Introduction===
  
 +**LinuxBIOS** supports a number of configuration options in CMOS. After booting, LinuxBIOS leaves a table in RAM which details the available option values. The table, and the current cmos settings are accessed by cmos_util.
 +
 +**cmos_util** //[-d | -u] [-s] [--image filename]//
 +
 +-d dumps current settings to stdout
 +
 +-u reads desired settings form stdin
 +
 +Because **cmos_util** must access system memory and can change the operation of the system, it must be run as root.
 +
 +The configuration format is human readable ASCII text consisting of options seperated by #####
 +
 +Within each group will be a series of <​option>​ = <​value>​ statements representing all of the possible values for the option. All but one will be commented out by a '#'​ at the beginning of the line.
 +
 +so:
 +
 +cmos_util -d >​cmos.config
 +
 +Would yield a file containing (amongst other options):
 +
 +#####
 +
 +baud_rate = 115200
 +# baud_rate = 57600
 +# baud_rate = 38400
 +# baud_rate = 19200
 +# baud_rate = 9600
 +# baud_rate = 4800
 +# baud_rate = 2400
 +# baud_rate = 1200
 +
 +
 +#####
 +
 +hyper_threading = Enable
 +# hyper_threading = Disable
 +
 +
 +
 +In the preceeding example, the serial console is to run at 115200 baud, and hyperthreading is to be enabled.
 +
 +To disable hyperthreading,​ edit the file to look like:
 +
 +#####
 +
 +baud_rate = 115200
 +# baud_rate = 57600
 +# baud_rate = 38400
 +# baud_rate = 19200
 +# baud_rate = 9600
 +# baud_rate = 4800
 +# baud_rate = 2400
 +# baud_rate = 1200
 +
 +
 +#####
 +
 +# hyper_threading = Enable
 +hyper_threading = Disable
 +
 +
 +
 +Then:
 +
 +cmos_util -u <​cmos.config ​
cmos.txt ยท Last modified: 2010/04/15 21:18 (external edit)