class SysInfo

def find_uptime

On Windows, see also: net statistics server
Based on Ruby Quiz solutions by: Matthias Reitinger
'sysctl -b kern.boottime' os osx, and 'who -b' on unix.
Returns the local uptime in hours. Use Win32API in Windows, 
def find_uptime
  hours = 0
  begin
    seconds = execute_platform_specific("find_uptime") || 0
    hours = seconds / 3600 # seconds to hours
  rescue => ex
    #puts ex.message  # TODO: implement debug?
  end
  hours
end