| release='', vendor='', vminfo=('','',''), osinfo=('','','')) | 
Returns a tuple (release, vendor, vminfo,
  osinfo) with vminfo being a tuple (vm_name,
  vm_release, vm_vendor) and osinfo being a tuple
  (os_name, os_version, os_arch).
  Values which cannot be determined are set to the defaults
  given as parameters (which all default to '').
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