Abstract: An embodiment of a method of virtualizing a counter in a computer system comprises a first step and iterative performance of second through fifth steps. In the first step, a virtual machine monitor programs a hardware event counter with an initial count for a profiling event for a virtual machine. In the second step, the virtual machine monitor saves a suspension count and disables the hardware event counter upon suspending operation of the virtual machine. In the third step, the virtual machine monitor programs the hardware event counter with the suspension count upon resuming the operation of the virtual machine. Upon receiving an interrupt from the hardware event counter that provides notification of reaching the initial count, the virtual machine monitor performs the fourth and fifth steps. In the fourth step, the virtual machine monitor saves a sample that comprises an event identifier and a code-in-execution indicator.

Abstract: A system and method for performing enhanced modeling of multi-tiered architectures is presented. The system and method enable selection of a preferred design for a multi-tiered architecture of components based on a set of established criteria, and may employ certain vectors and functions in component attributes, and such attributes may include scalability and scope of fault attributes.

Abstract: A multi-tenant virtual machine infrastructure (MTVMI) allows multiple tenants to independently access and use a plurality of virtual computing resources via the Internet. Within the MTVMI, different tenants may define unique configurations of virtual computing resources and unique rules to govern the use of the virtual computing resources. The MTVMI may be configured to provide valuable services for tenants and users associated with the tenants.

Abstract: A system and method for selecting a preferred design for a multi-tiered architecture of components based on a set of established criteria is provided. The system and method receive a model describing different design constructions and a set of performance and availability requirements and produces a design or set of designs that best meet these requirements. The system and method include a model for representing the infrastructure design space for multi-tier systems and their properties appropriate for judging performance and availability properties of services as well as associated cost. The method and system further include a method for searching the design space in an efficient manner.

Abstract: A system and method for performing enhanced modeling of multi-tiered architectures is presented. The system and method enable selection of a preferred design for a multi-tiered architecture of components based on a set of established criteria, and may employ certain vectors and functions in component attributes, and such attributes may include scalability and scope of fault attributes.

Abstract: A system and method for selecting a preferred design for a multi-tiered architecture of components based on a set of established criteria is provided. The system and method receive a model describing different design constructions and a set of performance and availability requirements and produces a design or set of designs that best meet these requirements. The system and method include a model for representing the infrastructure design space for multi-tier systems and their properties appropriate for judging performance and availability properties of services as well as associated cost. The method and system further include a method for searching the design space in an efficient manner.

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 multi-tenant virtual machine infrastructure (MTVMI) allows multiple tenants to independently access and use a plurality of virtual computing resources via the Internet. Within the MTVMI, different tenants may define unique configurations of virtual computing resources and unique rules to govern the use of the virtual computing resources. The MTVMI may be configured to provide valuable services for tenants and users associated with the tenants.

Abstract: A multi-tenant virtual machine infrastructure (MTVMI) allows multiple tenants to independently access and use a plurality of virtual computing resources via the Internet. Within the MTVMI, different tenants may define unique configurations of virtual computing resources and unique rules to govern the use of the virtual computing resources. The MTVMI may be configured to provide valuable services for tenants and users associated with the tenants.

Abstract: A method of detecting congestion in a communications network and a network switch are described. The method comprises identifying an output link of a network switch as a congested link on the basis of a packet in a queue of the network switch which is destined for the output link, where the output link has a predetermined state; and identifying a packet in a queue of the network switch as a packet generating congestion if the packet is destined for a congested link.

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.

Abstract: An embodiment of a method of virtualizing a process identifier begins with creation of a child process from a parent process. The parent process creates the child process by making a system call. If the parent process executes before the child process begins to execute, at a kernel level and without interruption the parent process maps a free virtual process identifier to a kernel process identifier for the child process. If the child process executes before the parent process begins to execute, at the kernel level and without interruption the child process determines the kernel process identifier. The child process then maps the free virtual process identifier to the kernel process identifier.

Abstract: A data center is designed by determining a compute description that describes computer resources to be used in the system from design requirements and models of the computer resources. A facility description that describes facilities to be used in the data center is determined from the compute description and models of the facilities. An integrated system describing the design of the data center is determined from the facility and compute descriptions.

Abstract: According to the present invention, there is provided a method for controlling congestion in a communications network, the method including receiving congestion feedback data relating to said network, adjusting at least one of a window limit and a rate limit based on said congestion feedback data and injecting data packets onto said network according to said window limit and said rate limit.

Abstract: An embodiment of a method of checkpointing parallel processes in execution within a plurality of process domains begins with a step of setting communication rules to stop communication between the process domains. Each process domain comprises an execution environment at a user level for at least one of the parallel processes. The method continues with a step of checkpointing each process domain and any in-transit messages. The method concludes with a step of resetting the communication rules to allow the communication between the process domains.

Abstract: A system comprising a first subsystem adapted to provide a service by executing a first code stored on the first subsystem. The system further comprises a second subsystem, communicably coupled to the first subsystem, on which a second code associated with the first code is stored. The second subsystem produces modified code by applying status files associated with the first code to the second code. The second subsystem provides the service in lieu of the first subsystem by executing the modified code.

Abstract: A method of checkpointing and restarting processes that share a file that is open begins with a step of assigning a priority to one of the processes that share the file. This identifies a priority process. The method concludes with a step of reopening the file when restoring the priority process.

Abstract: A method for data connectivity in a room with a robotic device. In the method, at least one condition is detected with a plurality of sensors and the detected at least one condition is communicated from the sensors to associated access points. One or more of the access points are selected and the robotic device is maneuvered to a location in a vicinity of one or more of the selected access points. The detected at least one condition is communicated from one or more of the selected access points to the robotic device. In addition, the robotic device is maneuvered to a location in a vicinity of a base station and the detected at least one condition is communicated from the robotic device to the base station.

Abstract: A cooling system for cooling computer systems detects heat dissipated by the computer systems. If the heat dissipated by the computer systems exceeds a threshold, at least one component of the computer systems is placed in a lower-power state to reduce heat dissipation.

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.