Abstract: Methods and systems described herein facilitate improving universal serial bus (USB) storage performance in remote computing environments. A virtual USB host is associated with a virtual machine running a guest operating system (OS) and is configured to communicate with a USB storage device that is connected to a remote terminal. The virtual USB host is further configured to transmit one of a data-in request to the USB storage device before the guest OS transmits the data-in request or an acknowledgement of a data-out request to the guest OS before the USB storage device transmits the acknowledgement.

Abstract: In a method for limiting access to a digital item, a count for the digital item is stored, wherein the count is a number of accesses permitted for the digital item. A password for accessing the digital item is received. A one-way hash function is performed on the password based on the number of accesses of the count to generate a password hash based on the count. The password hash is stored as the stored password hash.

Abstract: An approach to root cause determination in a complex systems based on monitoring and event data is disclosed. It includes a historical analysis of events with their probabilistic correlations. Applying information measures between the random variables which embody those events one can detect origins of problems and generate real-time recommendations for their locations in a hierarchical system. Estimation of system bottlenecks, as well as the risk of “black swan”-type events are also computed. The processes are based on a statistical processing of a virtual directed graph produced from historical events.

Abstract: Techniques for implicit co scheduling of CPUs to improve corun performance of scheduled contexts are described. One technique minimizes skew by implementing corun migrations, and another technique minimizes skew by implementing a corun bonus mechanism. Skew between schedulable contexts may be calculated based on guest progress, where guest progress represents time spent executing guest operating system and guest application code. A non-linear skew catch-up algorithm is described that adjusts the progress of a context when the progress falls far behind its sibling contexts.

Abstract: In one embodiment, a system for implementing a distributed, transactional key-value store is provided. The system includes a set of nodes, where each node is communicatively coupled with one or more storage devices storing a set of data log files, and where each data log file including key-value pairs for a key namespace. Each node is configured to execute, using a transaction log file specific to the node, transactions for modifying or retrieving key-value pairs in the set of data log files, where the transaction log file includes state information for the transactions. The transactions are executed in a manner that ensures the atomicity and durability of each transaction.

Abstract: In a computer system with a disk array that has physical storage devices arranged as logical storage units and is capable of carrying out hardware storage operations on a per logical storage unit basis, the hardware storage operations can be carried out on a per-file basis using various primitives. These primitives include instructions for zeroing file blocks, cloning file blocks, and deleting file blocks, and these instructions operate on one or more files defined in a blocklist, that identifies the locations in the logical storage units to which the files map.

Abstract: A method and system is provided for initializing files such as, for example and without limitation, pre-allocated files or raw device mapping (RDM) files, by delaying initializing file blocks. In accordance with one or more embodiments of the present invention, file blocks are associated with corresponding indicators to track un-initialized blocks.

Abstract: In a computer system supporting execution of virtualization software and at least one instance of virtual system hardware, an interface is provided into the virtualization software to allow a program to directly define the access characteristics of its program data stored in physical memory. The technique includes providing data identifying memory pages and their access characteristics to the virtualization software which then derives the memory access characteristics from the specified data. Optionally, the program may also specify a pre-defined function to be performed upon the occurrence of a fault associated with access to an identified memory page. In this manner, programs operating both internal and external to the virtualization software can protect his memory pages, without intermediation by the operating system software.

Abstract: A method and tangible medium embodying code for allocating resource units of an allocatable resource among a plurality of clients in a computer is described. In the method, resource units are initially distributed among the clients by assigning to each of the clients a nominal share of the allocatable resource. For each client, a current allocation of resource units is determined. A metric is evaluated for each client, the metric being a function both of the nominal share and a usage-based factor, the usage-based factor being a function of a measure of resource units that the client is actively using and a measure of resource units that the client is not actively using. A resource unit can be reclaimed from a client when the metric for that client meets a predetermined criterion.

Abstract: A virtualization platform provides fault tolerance for a primary virtual machine by continuously transmitting checkpoint information of the primary virtual machine to a collector process, such as a backup virtual machine. When implemented on a hardware platform comprising a multi-processor that supports nested page tables, the virtualization platform leverages the nested page table support to quickly identify memory pages that have been modified between checkpoints. The backup virtual machine provides feedback information to assist the virtualization platform in identifying candidate memory pages for transmitting actual modifications to the memory pages rather than the entire memory page as part of the checkpoint information. The virtualization platform further maintains a modification history data structure to identify memory pages that can be transmitted simultaneous with the execution of the primary virtual machine rather than while the primary virtual machine has been stunned.

Abstract: A computer readable storage medium containing a program which, when executed by a processor, performs an operation of emulating static thread local storage of an executable software code at runtime, is disclosed. The operation includes executing the executable software code within a process memory space. During the execution of the executable software code, an occurrence of an event that is associated with a thread create operation is monitored. When the monitored event occurs, a thread data block duplicate is established within the process memory space and associated with a thread created by the thread create operation. The thread data block duplicate is configured to be accessed by executing a thread local storage callback function.

Abstract: Methods and systems for n-way cloning and synchronization of a user desktop image are provided. Example embodiments provide a Cloning and Synchronization System (“CSS”) which binds a server stored CVD object representing the user's desktop image to one or more endpoint devices. Each endpoint device receives a clone of the CVD object that comprises one or more layers of the server CVD depending upon the suitability of the endpoint device hardware and operating system to the server stored desktop. The cloned CVDs in the endpoint devices are then kept synchronized by synchronization operations. In one embodiment, the CSS allows only one endpoint device to push up changes to the server CVD. User files are synchronized with the all endpoints using a live sync process. System and managed applications may be intelligently merged into an inactive device rather than overwriting data modified on the inactive device.

Abstract: A computing device employs a cooperative memory management technique to dynamically balance memory resources between host and guest systems running therein. According to this cooperative memory management technique, memory that is allocated to the guest system is dynamically adjusted up and down according to a fairness policy that takes into account various factors including the relative amount of readily freeable memory resources in the host and guest systems and the relative amount of memory allocated to hidden applications in the host and guest systems.

Abstract: One or more embodiments provide methods of creating datacenter capacity and/or load models for a datacenter in a virtualized environment; methods of simulating the capacity and/or load models (“What-if” simulations); and methods of visualizing simulation results for assessing the impact of the capacity and/or load models on the datacenter capacity.

Abstract: Available buffers in the memory space of a guest operating system of a virtual machine are provided to a network interface controller (NIC) for use during direct memory access (DMA) and the guest operating system is notified accordingly when data is written into such available buffers. These capabilities obviate the requirement of using hypervisor memory as a staging area to determine which virtual machine to forward incoming data.

Abstract: A management technique for input/output operations (JO) leverages a hypervisor's position as an intermediary between virtual machines (VMs) and storage devices servicing the VMs to facilitate improvements in overall I/O performance for the VMs. According to this new I/O management technique, the hypervisor sends write requests from VMs destined for storage devices to an I/O staging device that provides higher I/O performance than the storage devices, for caching in the I/O staging device in a write-back mode. Once the I/O staging device has received and acknowledged the write request, the hypervisor immediately provides an acknowledgement to the requesting VM. Later on and asynchronously with respect to the write requests from the VMs, the hypervisor reads the write data from the I/O staging device and sends it over to the storage devices for storage therein.

Abstract: Available buffers in the memory space of a guest operating system of a virtual machine are provided to a network interface controller (NIC) for use during direct memory access (DMA) and the guest operating system is notified accordingly when data is written into such available buffers. These capabilities obviate the requirement of using hypervisor memory as a staging area to determine which virtual machine to forward incoming data.

Abstract: Autonomous selection between multiple virtualization techniques implemented in a virtualization layer of a virtualized computer system. The virtual machine monitor implements multiple virtualization support processors that each provide for the comprehensive handling of potential virtualization exceptions. A virtual machine monitor resident virtualization selection control is operable to select between use of first and second virtualization support processors dependent on identifying a predetermined pattern of temporally local privilege dependent instructions within a portion of an instruction stream as encountered in the execution of a guest operating system.

Abstract: A remote proxy provides remote control to a virtualization system. The virtualization system includes a computer having virtualization software executing on the computer, and one or more virtual machines executing on the computer by way of the virtualization software, each of the virtual machines having a guest operating system. The remote proxy receives over a network connection a plurality of logical channels of a multi-channel remote control protocol at a first domain of a plurality of domains of the virtualization system. Each of the logical channels convey information corresponding to one of the domains. For each logical channel, the remote proxy identifies the corresponding domain. Further, for each of the logical channels corresponding to a domain other than the first domain, the remote proxy forwards the logical channel to the corresponding domain.

Abstract: Methods and apparatus are disclosed for managing access to data in a data storage system. For example, an apparatus comprises at least one processing platform associated with a distributed virtual infrastructure. The processing platform comprises at least one processing device having a processor coupled to a memory. The processing platform is operative to instantiate a meta data management process that is configured to provide at least one client process with information to allow the client process to perform one or more operations in accordance with one or more data storage devices through a storage area network. The information provided to the client process may comprise one or more data block descriptors. Each of the one or more data block descriptors may comprise path information for at least one of the data storage devices and an offset address in the at least one data storage device.