nvram(7)                                                 nvram(7)



NAME
     nvram - provides an interface to nonvolatile memory

DESCRIPTION
     nvram is a device driver that provides access to  256  bytes
     of  nonvolatile  memory,  also  known  as PRAM.  This memory
     retains values stored in it even when the system's power  is
     turned off.

     Any user can  read  the  special  device  /dev/nvram,  which
     returns  up to 256 bytes.  The bytes are the contents of the
     nonvolatile RAM.  To write to /dev/nvram, however, you  must
     be logged in as root.

     If the device is already open, an attempt to open it  causes
     the system to return the error EBUSY.  This behavior ensures
     that a process can perform read-modify-write  operations  on
     the device.  If an attempt to open the device results in the
     error EBUSY, the process should wait a while  and  then  try
     again.   After the device is opened successfully, the device
     should be kept open only as long as necessary.

WARNINGS
     Take care when writing to this device.  The contents of  the
     nonvolatile  RAM  are defined by Apple Computer and are used
     by many parts of  both  A/UX  and  the  Macintosh  Operating
     System.  For this reason, indiscriminate writing could cause
     your system to malfunction.   Usually  you  should  use  the
     utilities provided to manipulate the contents of nvram.

FILES
     /dev/nvram
          Device file
     /usr/include/sys/nvram.h
          Header file

SEE ALSO
     stime(2), time(2)

     date(1) in A/UX Command Reference















January 1992                                                    1