1. A control system for controlling a process, the system comprising:
a safety module and an output module, with the safety module providing a secure signal, the output module comprising an output to issue the secure signal (4) for controlling the process, the output module comprising a means for the detection of an actual status of the output,
wherein the detected actual status is compared via the safety module with a target status, and in case of a difference between the actual status and the target status, the process is transferred into a safe mode.
2. A control system according to claim 1, wherein the process can be transferred into a safe mode by shutting off the secure signal.
3. A control system according to claim 1, wherein at least one of a control and a secure control is provided to address at least one of the safety module and the output module and the target status is can be predetermined by at least one of the control and by the secure control.
4. A control system according to claim 3, wherein the detected actual status is transmitted by the output module to at least one of the control and the secure control and the detected actual status transmitted by at least one of the control and the secure control to the safety module.
5. A control system according to claim 3, wherein a field bus is predetermined for the communication between the safety module, the output module, and at least one of the control and the secure control.
6. A control system according to claim 1, with the control system being embodied as a field bus arrangement.
7. The use of a control system according to claim 1 for the automation of an arrangement.
8. A control device for controlling a process, comprising:
a safety module and an output module, with the safety module comprising an energy source for providing a secure signal, the safety module comprising a comparison means for comparing an actual status with a target status and a shut-off means for transferring the process into a safe mode,
wherein the output module comprises an output for issuing the secure signal for controlling the process, and the output module comprising a means for the detection of the actual status of the output.
9. A control device according to claim 8, with the shut-off means being embodied such that the shut-off means transfers the process into a safe mode by shutting off the secure signal.
10. A control device according to claim 8, wherein at least one of a control and a secure control is provided to control at least one of the safety module and the output module and the target state is predetermined by at least one of the control and the secure control.
11. A control device according to claim 10, wherein the detected actual state is transmitted from the output module to at least one of the control and the secure control, and the detected actual status is transmitted from at least one of the control and the secure control to the safety module.
12. A control device according to claim 10, with a field bus being provided for the communication between the safety module, the output module, and at least one of the control and the secure control.
13. A method for controlling a process with a safety module and an output module, comprising the steps:
providing of a secure signal by the safety module;
issuing of the secure signal to control the process by the output module, wherein detection of the actual status of the issued secure signal is performed by the output module; and
determining a difference between the actual status and a target status for the process by the safety module, and transfer of the process into a safe mode when there is a difference.
14. A method according to claim 13, wherein the transfer of the process into the safe mode occurs by shutting off the secure signal.
15. A method according to claim 13, with at least one of a control and a secure control to control at least one of the safety module and the output module being provided, comprising the steps:
predetermining of the actual status by at least one of the control and the secure control;
communicating the actual status via the output module to at least one of the control and the secure control; and
communicating the detected actual status by at least one of the control and the secure control to the safety module.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for generating a checkpoint image of an in-memory database system, comprising:
identifying one or more storage pages which have been modified but not incorporated into a previous checkpoint image;
for each identified storage page, identifying a direct memory reference and its offset which correspond to a secondary storage location;
for each identified storage page, identifying one or more leaf nodes of a primary index and a secondary index and a memory address of each database table row identified in each of the identified leaf nodes;
for each of the identified memory addresses of each database table row, identifying a relation identifier of a database table of each of the database rows; and
writing the identified direct memory references, the offsets, a relation identifier directory, and the identified leaf nodes of the primary and secondary indexes to a checkpoint image.
2. The method as claimed in claim 1, wherein the identified relation identifiers are stored in the relation identifier directory.
3. The method as claimed in claim 1, further comprising a disk address array for storing the offsets of the direct memory references.
4. The method as claimed in claim 1, further comprising a row address translation table for translation of direct memory references to the secondary storage locations, the row address translation table being ordered by before-checkpoint tuple addresses, wherein the row address translation table is also written to the checkpoint image.
5. The method as claimed in claim 1, wherein the leaf nodes are leaf nodes of a B+-tree.
6. The method as claimed in claim 1, wherein the leaf nodes are leaf nodes of a hashed index data structure.
7. The method as claimed in claim 1, wherein each identified direct memory reference and its offset, each identified relation identifier, and each identified leaf node of the primary index and the secondary index is buffered to a checkpoint buffer before writing to the checkpoint image.
8. The method as claimed in claim 1, further comprising initiating a checkpoint operation and preventing updates to the primary index and the secondary index and the storage pages during the checkpoint operation.
9. The method as claimed in claim 1, further comprising restoring a database from the checkpoint image.