Abstract: A hypervisor environment configured for accelerated access to device emulators comprises a hypervisor that intercepts a device access instruction to a child partition processor and routes said device access instruction to a root partition. A processor instruction emulator emulates said device access instruction along with any number of next instructions of the processor in said child partition, thereby dispatching accesses to a device emulator on behalf of the processor in said child partition. By emulating these instructions in the root partition, accesses to the device emulator are greatly accelerated.

Abstract: In exemplary embodiments, device capabilities, i.e., functions performed in a hardware device, can be selectively enabled/disabled in a virtual machine by modifying configuration information for a hardware device emulator. For example, the configuration information can be changed in order to cause a guest operating system to load a specific device driver that enables/disables select hardware capabilities in a virtual machine. Other techniques are described in the claims, detailed description, and drawings.

Abstract: Techniques for migrating a virtual machine from a source computer system to a target computer system are disclosed. In an exemplary embodiment, a group of pages can be mapped writable in response to determining that the guest operating system attempted to change a specific page. In the same, or other embodiments, pages can be compressed prior to sending such that throughput of a communication channel is maximized. In the same, or other embodiments, storage IO jobs can be canceled on a source computer system and reissued by a target computer system.

Abstract: Media data is distributed across multiple devices and is locatable using a hashing function and a hash table. The media data is partially replicated based on popularity thereof. In a described implementation, a media data block is locatable by hashing a media data indicator to produce a media data hash value that maps to a bin of the hash table. The bin is associated with at least one device that stores and/or with a sender that is capable of sending to clients the media data blocks mapping thereto. Each bin may have primary and secondary roles. Devices holding primary roles store all of the media data blocks mapping to a bin. Devices holding secondary roles replicate the media data blocks mapping to the bin that are also within a top predetermined popularity percentage. Popularity is determined based on numbers of clients currently requesting a particular media data portion.

Abstract: Described is a technology by which a virtual hard disk is maintained between a far (e.g., remote) backing store and a near (e.g., local) backing store, which among other advantages facilitates fast booting of a machine coupled to the virtual hard disk. Read requests are serviced from the near backing store (e.g., a differencing layer) when the data is available thereon, or from the far backing store (e.g., a base layer) when not. The near backing store may be configured with a cache layer that corresponds to the base layer and a write differencing layer that stores writes, or a single differencing layer may be used for both caching read data and for storing write data. A background copy operation may be used to fill the cache until the far backing store data is no longer needed.

Abstract: Described is a technology by which a virtual hard disk is able to continue servicing virtual disk I/O (reads and writes) while a meta-operation (e.g., copying, moving, deleting, merging, compressing, defragmenting, cryptographic signing, lifting, dropping, converting, or compacting virtual disk data) is performed on the virtual disk. The servicing of virtual disk I/Os may be coordinated with meta-operation performance, such as by throttling and/or prioritizing the virtual disk I/Os. Also described is performing a meta-operation by manipulating one or more de-duplication data structures.

Abstract: Described is a technology by which a virtual hard disk is migrated from a source storage location to a target storage location without needing any shared physical storage, in which a machine may continue to use the virtual hard disk during migration. This facilitates use the virtual hard disk in conjunction with live-migrating a virtual machine. Virtual hard disk migration may occur fully before or after the virtual machine is migrated to the target host, or partially before and partially after virtual machine migration. Background copying, sending of write-through data, and/or servicing read requests may be used in the migration. Also described is throttling data writes and/or data communication to manage the migration of the virtual hard disk.

Abstract: A virtual machine storage service can be use a unique network identifier and a SR-IOV compliant device can be used to transport I/O between a virtual machine and the virtual machine storage service. The virtual machine storage service can be offloaded to a child partition or migrated to another physical machine along with the unique network identifier.

Abstract: Techniques for migrating lightweight services in a datacenter are described. In an example embodiment the services can be attached to virtual ports of embedded switches and assigned unique network identifiers. The services can be migrated from one physical host to another by migrating the unique identifiers and associating them with instantiated instances of at least equivalent services.

Abstract: Various aspects are disclosed herein for replacing the hardware backing the memory locations associated with a virtual machine with a backing mechanism. The backing mechanism may have the memory locations appear to contain data convenient to the driver in the virtual machine, typically containing what the hardware would have returned if the hardware had been read from. The data image being returned from the memory locations may travel with the virtual machine even if the virtual machine moves to a different physical machine that does not contain hardware equivalent to the hardware that was recently removed from the virtual machine.

Abstract: Accelerated channel change (ACC) strategies are described for supplying a client module with media information by transitioning between a first delivery of media information provided by first delivery functionality and a second delivery of media information provided by second delivery functionality without exceeding prescribed data rate limitations. The first delivery functionality can represent server-based functionality for delivering a unicast stream of media information at a data rate (or maximum data rate) of some excess amount over the nominal rate of delivery, starting at a selected location within the media information. The second delivery functionality can represent any functionality for delivering the media information at the data rate (or maximum data rate) of the nominal rate of delivery. A join interval separates the first delivery at the excess rate and the second delivery at the nominal rate.

Abstract: Various aspects are disclosed herein for replacing the hardware backing the memory locations associated with a virtual machine with a backing mechanism. The backing mechanism may have the memory locations appear to contain data convenient to the driver in the virtual machine, typically containing what the hardware would have returned if the hardware had been read from. The data image being returned from the memory locations may travel with the virtual machine even if the virtual machine moves to a different physical machine that does not contain hardware equivalent to the hardware that was recently removed from the virtual machine.

Abstract: Strategies are described for performing retry analysis in an environment which involves the transmission of media information from a source module to a target module. In the context of the source module, the retry analysis determines whether the source module should satisfy the retry requests issued by the target module. In the context of the target module, the retry analysis determines whether the target module should generate the retry requests in the first place. Novel request reporting formats are also described. The target module performs analysis to determine what reporting format it should use to convey the retry requests to the source module.

Abstract: Saving state of Random Access Memory (RAM) in use by guest operating system software is accomplished using state saving software that starts a plurality of compression threads for compressing RAM data blocks used by the guest. Each compression thread determines a compression level for a RAM data block based on a size of a queue of data to be written to disk, then compresses the RAM data block, and places the compressed block in the queue.

Abstract: Various aspects are disclosed herein for replacing the hardware backing the memory locations associated with a virtual machine with a backing mechanism. The backing mechanism may have the memory locations appear to contain data convenient to the driver in the virtual machine, typically containing what the hardware would have returned if the hardware had been read from. The data image being returned from the memory locations may travel with the virtual machine even if the virtual machine moves to a different physical machine that does not contain hardware equivalent to the hardware that was recently removed from the virtual machine.

Abstract: Improved hardware throughput can be achieved when a hardware device is saturated with IO jobs. Throughput can be estimated based on the quantifiable characteristics of incoming IO jobs. When IO jobs are received a time cost for each job can be estimated and stored in memory. The estimates can be used to calculate the total time cost of in-flight IO jobs and a determination can be made as to whether the hardware device is saturated based on completion times for IO jobs. Over time the time cost estimates for IO jobs can be revised based on a comparison between the estimated time cost for an IO job and the actual time cost for the IO job using aggregate IO job completion sequences.

Abstract: Batching techniques are provided to maximize the throughput of a hardware device based on the saturation point of the hardware device. A balancer can determine the saturation point of the hardware device and determine the estimated time cost for IO jobs pending in the hardware device. A comparison can be made and if the estimated time cost total is lower than the saturation point one or more IO jobs can be sent to the hardware device.

Abstract: Techniques are disclosed for managing the flow of IO jobs from a client to a hardware device such that resource starvation is reduced without significantly impacting throughput. Each flow can be assigned an amount of time that a hardware device can deplete completing IO jobs from the client. When the allocated amount of time is used IO jobs associated with the client can be stored in a queue until the client obtains more time.

Abstract: Mechanisms are provided for the sharing of graphics adapter resources among multiple partitions in a virtual machine environment. A first mechanism allows for the sharing of graphics adapter resources so that one partition, a video service partition, containing a graphics proxy process, can use this graphics proxy process to offer graphics adapter resources to another partition, a video client partition. The graphics proxy process controls access time by any given partition to the graphics adapter resources. In one aspect, it uses a time bank to control access time, and the time bank controls how long a virtual graphics adapter offered to the video client partition can access the graphics adapter resources. A second mechanism synchronizes virtual memory in the video client partition to virtual memory in the video service partition. A third mechanism allows for multiple video client partition overlays using a pixel-shader-based virtual overlay mechanism.

Abstract: Described herein is a technology facilitating the presentation of digital video streams. An implementation, described herein, reduces the effective start-up delay in the presentation of the first frames of the video content that occurs when a system tunes into a video stream. This abstract itself is not intended to limit the scope of this patent. The scope of the present invention is pointed out in the appending claims.