cpr(7)                                                     Device and Network Interfaces                                                    cpr(7)

NAME

       cpr - Suspend and resume module

SYNOPSIS

       /platform/'uname -m'/kernel/misc/cpr

DESCRIPTION

       The  cpr  module  is  a  loadable module used to suspend and resume the entire system. You may wish to suspend a system to save power or to
       power off temporarily for transport. The cpr module should not be used in place of a normal shutdown when performing any hardware reconfig-
       uration or replacement. In order for the resume operation to succeed, it is important that the hardware configuration remain the same. When
       the system is suspended, the entire system state is preserved in non-volatile storage until a resume operation is conducted.

       dtpower(1M) or power.conf(4) are used to configure the suspend-resume feature.

       The speed of suspend  and resume operations can range from 15 seconds to several minutes, depending on the system speed, memory  size,  and
       load.

       During  resume  operation,  the  SIGTHAW signal is sent to all processes to allow them to do any special processing in response to suspend-
       resume operation. Normally applications are not required to do any special processing because of suspend-resume, but some specialized  pro-
       cesses can use  SIGTHAW to restore the state prior to suspend. For example, X can refresh the screen in response to SIGTHAW.

       In  some  cases the cpr module may be unable to perform the suspend operation. If a system contains additional devices outside the standard
       shipped configuration, it is possible that device drivers for these additional devices might not  support  suspend-resume   operations.  In
       this  case,  the  suspend  fails  and an error message is displayed. These devices must be removed or their device drivers unloaded for the
       suspend operation to succeed.  Contact the device manufacturer to obtain a new version of device driver that supports suspend-resume.

       A  suspend  may also fail when devices or processes are performing critical or time-sensitive operations (such as realtime operations). The
       system will remain in its current running state. Messages reporting the failure will be displayed on the console and status returned to the
       caller. Once the system is successfully suspended the resume operation will succeed, barring external influences such as a hardware  recon-
       figuration.

       Some network-based applications may fail across a suspend and resume
        cycle.  This  largely  depends  on the underlying network protocol and the applications involved.  In general, applications that retry and
       automatically reestablish connections will continue to operate  transparently on a resume  operation; those applications that do  not  will
       likely fail.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWcpr                      |
       +-----------------------------+-----------------------------+
       |Interface stability          |Unstable                     |
       +-----------------------------+-----------------------------+

SEE ALSO

       dtpower(1M) (OpenWindows Reference Manual), pmconfig(1M), uadmin(1M), uadmin(2), power.conf(4), attributes(5)

       Using Power Management

       Writing Device Drivers

NOTES

       Certain device operations such as tape and floppy disk activities are not resumable due to the nature of removable media.  These activities
       are detected at suspend time, and must be stopped before the suspend  operation will complete successfully.

       Suspend-resume is currently  supported only on a limited set of hardware platforms. Please see  the book Using Power Management for a  com-
       plete  list  of  platforms that support system Power Management. See uname(2) to programatically determine if the machine supports suspend-
       resume.

SunOS 5.10                                                          7 May 2001                                                              cpr(7)