Abstract: A method for replicating a program and data storage according to one embodiment comprises sending program replication data from a first program to a second program, the second program having an application program that is a replica of an application program of the first program; sending data storage requests from the first program to a first storage system; and replicating data stored in the first storage system in a second storage system. Additional methods, systems, and computer program products are disclosed.

Abstract: A method, computer program and system for controlling accesses to memory by threads created by a process executing on a multiprocessor computer. A page table structure is allocated for each new thread and copied from the existing threads. The page access is controlled by a present bit and a writable bit. Upon a page fault the access is provided to one thread. The kernel handles the new page entry creation process and set the page present bits to zero which creates page faults. In a second embodiment, two page table structures are created, one for one thread having access to the address space and the other page table structure shared by all the other threads not having access to the address space.

Abstract: Provided are a method, system, and program for gathering pages allocated to an application to include in checkpoint information. A call from an application is intercepted to allocate memory pages to cause indication of pages allocated to the application that have modified data. An operation is initiated to create checkpoint information for the application. Pages allocated to the application that have modified data are determined in response to the operation to create the checkpoint information. The determined pages are saved in the checkpoint information.

Abstract: A method, system and program product for recording a program execution comprising recording processor context for each thread of the program, results of system calls by the program, and memory pages accessed by the program during an execution interval in a checkpoint file. Processor context includes register contents and descriptor entries in a segment descriptor table of the operating system. System calls are recorded for each program thread, tracked by an extension to the operating system kernel and include returned call parameter data. Accessed memory pages are recorded for each program process and include data, libraries and code pages. The program address space, processor context, and program threads are reconstructed from checkpoint data for replaying the program execution in a different operating system environment.

Abstract: A method for replicating a program and data storage according to one embodiment comprises sending program replication data from a first program to a second program, the second program having an application program that is a replica of an application program of the first program; sending data storage requests from the first program to a first storage system; and replicating data stored in the first storage system in a second storage system. Additional methods, systems, and computer program products are disclosed.

Abstract: A method for replicating a program and data storage according to one embodiment comprises sending program replication data from a first program to a second program, the second program having an application program that is a replica of an application program of the first program; sending data storage requests from the first program to a first storage system; and replicating data stored in the first storage system in a second storage system. Additional methods, systems, and computer program products are disclosed.

Abstract: Provided are a method, system, and article of manufacture for gathering state information for an application and kernel components called by the application. An implementation of a component to execute in a kernel space is instantiated in a user space. An application invokes a call to the component in the kernel space. The call to the component in the kernel space is invoked and an implementation of the component in the user space is invoked to execute the call in the user space. State information related to the execution of the call to the component in the user space to include in checkpoint information for the application is gathered.

Abstract: Provided are a method, system, and article of manufacture for varying access parameters for processes to access memory addresses in response to detecting a condition related to a pattern of processes access to memory addresses. A monitored condition is detected during application execution. An instrumentation program is invoked to monitor processes accessing data at addresses in a memory device in response to detecting the monitored condition. Information is logged on processes and the addresses they access in the memory device in response to invoking the instrumentation program. The logged information on the processes and the addresses they access is forwarded to an application analysis system in response to detecting a monitored condition during application execution.

Abstract: A method, system and program product for recording a program execution comprising recording processor context for each thread of the program, results of system calls by the program, and memory pages accessed by the program during an execution interval in a checkpoint file. Processor context includes register contents and descriptor entries in a segment descriptor table of the operating system. System calls are recorded for each program thread, tracked by an extension to the operating system kernel and include returned call parameter data. Accessed memory pages are recorded for each program process and include data, libraries and code pages. The program address space, processor context, and program threads are reconstructed from checkpoint data for replaying the program execution in a different operating system environment.

Abstract: Provided are a method, system, and article of manufacture for monitoring patterns of processes accessing addresses in a storage device to determine access parameters to apply. Processes accessing addresses of data in a storage device are monitored. The processes are granted access to the addresses according to first access parameters that indicate how to arbitrate access by processes to the addresses. A condition occurring in response to a pattern of processes accessing addresses is detected. A determination is made of one of the processes in the pattern and the address accessed by the determined process. Indication is made that second access parameters apply for the determined address. The second access parameters are used to grant access to the determined address for subsequent accesses of the indicated address.

Abstract: Provided are a method, system, and article of manufacture for providing a process exclusive access to a page including a memory address to which a lock is granted to the process. A request is received for a memory address in a memory device from a requesting process. A lock is granted to the requested memory address to the requesting process. The requesting process is provided exclusive access to a page including the requested memory address for a page access time period. The exclusive access to the page provided to the requesting process is released in response to an expiration of the page access time period.

Abstract: Provided are a method, system, and article of manufacture for checkpointing and restoring user space data structures used by an application accessing a data structure maintained by an operating system for an executing application. Information in the accessed data structure is saved with checkpoint information for the application. An operation to restore the application from the checkpoint information is initialized. A restored data structure is generated to include the saved information in the accessed data structure saved in the checkpoint information in response to restoring the application. An initialization routine of the application is modified to bypass initializing the data structure as part of the application initialization routine to restore the application.

Abstract: Provided are a method, system, and article of manufacture for recovery of application faults in a mirrored application environment. Application events are recorded at a primary system executing an instruction for an application. The recorded events are transferred to a buffer. The recorded events are transferred from the buffer to a secondary system, wherein the secondary system implements processes indicated in the recorded events to execute the instructions indicated in the events. An error is detected at the primary system. A determination is made of a primary order in which the events are executed by processes in the primary system. A determination is made of a modified order of the execution of the events comprising a different order of executing the events than the primary order in response to detecting the error. The secondary system processes execute the instructions indicated in the recorded events according to the modified order.

Abstract: An embodiment of a method of restoring a communication state of a process includes creating a new socket for a socket saved as part of a checkpoint of the communication state. The new socket is initialized with an adjusted transmission control protocol state saved as part of the checkpoint. The adjusted transmission control protocol state indicates that a send buffer and a receive buffer are empty. Send data saved as part of the checkpoint is written into the new socket. Receive data saved as part of the checkpoint is written into a restart buffer. While at least a portion of the receive data remains in the restart buffer, a socket read system call for the new socket is redirected to read the receive data that remains in the restart buffer.

Abstract: A method, computer program and system for controlling accesses to memory by threads created by a process executing on a multiprocessor computer. A page table structure is allocated for each new thread and copied from the existing threads. The page access is controlled by a present bit and a writable bit. Upon a page fault the access is provided to one thread. The kernel handles the new page entry creation process and set the page present bits to zero which creates page faults. In a second embodiment, two page table structures are created, one for one thread having access to the address space and the other page table structure shared by all the other threads not having access to the address space.

Abstract: A method for replicating a program and data storage according to one embodiment comprises sending program replication data from a first program to a second program, the second program having an application program that is a replica of an application program of the first program; sending data storage requests from the first program to a first storage system; and replicating data stored in the first storage system in a second storage system. Additional methods, systems, and computer program products are disclosed.

Abstract: Provided are a method, system, and program for gathering pages allocated to an application to include in checkpoint information. A call from an application is intercepted to allocate memory pages to cause indication of pages allocated to the application that have modified data. An operation is initiated to create checkpoint information for the application. Pages allocated to the application that have modified data are determined in response to the operation to create the checkpoint information. The determined pages are saved in the checkpoint information.

Abstract: Provided are a method, system, and article of manufacture for checkpointing and restoring user space data structures used by an application accessing a data structure maintained by an operating system for an executing application. Information in the accessed data structure is saved with checkpoint information for the application. An operation to restore the application from the checkpoint information is initialized. A restored data structure is generated to include the saved information in the accessed data structure saved in the checkpoint information in response to restoring the application. An initialization routine of the application is modified to bypass initializing the data structure as part of the application initialization routine to restore the application.

Abstract: Provided are a method, system, and article of manufacture for gathering state information for an application and kernel components called by the application. An implementation of a component to execute in a kernel space is instantiated in a user space. An application invokes a call to the component in the kernel space. The call to the component in the kernel space is invoked and an implementation of the component in the user space is invoked to execute the call in the user space. State information related to the execution of the call to the component in the user space to include in checkpoint information for the application is gathered.

Abstract: An embodiment of a method of performing a kernel level task upon initial execution of a child process at a user level begins with setting an instruction pointer for an initial child process instruction to an instruction to enter a kernel level. The method continues with beginning the child process which places a return value in a register for the child process and which causes the child process to enter the kernel level. The method concludes with executing a system call having a system call number of the return value. The system call comprises the kernel level task.