A determination can be made of how changes to underlying data affect the value of objects. Examples of applications include: caching dynamic Web pages; client-server applications whereby a server sending objects (which are changing all the time) to multiple clients can track which versions are sent to which clients and how obsolete the versions are; and any situation where it is necessary to maintain and uniquely identify several versions of objects, update obsolete objects, quantitatively assess how different two versions of the same object are, and/or maintain consistency among a set of objects. A directed graph, called an object dependence graph, may be used to represent the data dependencies between objects. Another aspect is constructing and maintaining objects to associate changes in remote data with cached objects. If data in a remote data source changes, database change notifications are used to "trigger" a dynamic rebuild of associated objects. Thus, obsolete objects can be dynamically replaced with fresh objects. The objects can be complex objects, such as dynamic Web pages or compound-complex objects, and the data can be underlying data in a database. The update can include either: storing a new version of the object in the cache; or deleting an object from the cache. Caches on multiple servers can also be synchronized with the data in a single common database. Updated information, whether new pages or delete orders, can be broadcast to a set of server nodes, permitting many systems to simultaneously benefit from the advantages of prefetching and providing a high degree of scaleability.

Determining how changes to underlying data affect cached objects

The present invention provides a system for creating an application software environment without changing an operating system of a client computer, the system comprising an operating system abstraction and protection layer, wherein said abstraction and protection layer is interposed between a running software application and said operating system, whereby a virtual environment in which an application may run is provided and application level interactions are substantially removed. Preferably, any changes directly to the operating system are selectively made within the context of the running application and the abstraction and protection layer dynamically changes the virtual environment according to administrative settings. Additionally, in certain embodiments, the system continually monitors the use of shared system resources and acts as a service to apply and remove changes to system components. The present thus invention defines an “Operating System Guard.” These components cover the protection semantics required by .DLLs and other shared library code as well as system device drivers, fonts, registries and other configuration items, files, and environment variables.

Operating system abstraction and protection layer

A determination can be made of bow changes to underlying data affect the value of objects. Examples of applications are: caching dynamic Web pages; client-server applications whereby a server sending objects (which are changing all the time) to multiple clients can track which versions are sent to which clients and how obsolete the versions are; and any situation where it is necessary to maintain and uniquely identify several versions of objects, update obsolete objects, quantitatively assess how different two versions of the same object are, and/or maintain consistency among a set of objects. A directed graph called an object dependence graph, may be used to represent the data dependencies between objects. Another aspect is constructing and maintaining objects to associate changes in remote data with cached objects. If data in a remote data source changes, database change notifications are used to “trigger” a dynamic rebuild of associated objects. Thus, obsolete objects can be dynamically replaced with fresh objects. The objects can be complex objects, such as dynamic Web pages or compound-complex objects, and the data can be underlying data in a database. The update can include either storing a new version of the object in the cache; or deleting an object from the cache. Caches on multiple servers can also be synchronized with the data in a single common database. Updated information, whether new pages or delete orders, can be broadcast to a set of server nodes, permitting many systems to simultaneously benefit from the advantages of prefetching and providing a high degree of scaleability.

Scaleable method for maintaining and making consistent updates to caches

An interprise computing manager in which an application is composed of a client
(front end) program which communicates utilizing a network with a server (back
end) program. The client and server programs are loosely coupled and exchange
information using the network. The client program is composed of a User
Interface (UI) and an object-oriented framework (Presentation Engine (PE)
framework). The UI exchanges data messages with the framework. The
framework is designed to handle two types of messages: (1) from the UI, and (2)
from the server (back end) program via the network. The framework includes a
component, the mediator which manages messages coming into and going out of
the framework. The system includes software for a client computer, a server
computer and a network for connecting the client computer to the server
computer which utilize an execution framework code segment configured to
couple the server computer and the client computer via the network, by a
plurality of client computer code segments resident on the server, each for
transmission over the network to a client computer to initiate coupling; and a
plurality of server computer code segments resident on the server which execute
on the server in response to initiation of coupling via the network with a
particular client utilizing the transmitted client computer code segment for
communicating via a particular communication protocol. Communication is
initiated utilizing the network to acquire characteristics of the client from the
network.

Object-oriented system, method and article of manufacture for a client-server session WEB access in an interprise computing framework system

Transitions among schedulable entities executing in a computer system are tracked in computer hardware or in a virtual machine monitor. In one aspect, the schedulable entities are operating system processes and threads, virtual machines, and instruction streams executing on the hardware. In another aspect, the schedulable entities are processes or threads executing within the virtual machines under the control of the virtual machine monitor. The virtual machine monitor derives scheduling information from the transitions to enable a virtual machine system to guarantee adequate scheduling quality of service to real-time applications executing in virtual machines that contain both real-time and non-real-time applications. In still another aspect, a parent virtual machine monitor in a recursive virtualization system can use the scheduling information to schedule a child virtual machine monitor that controls multiple virtual machines.

Tracking operating system process and thread execution and virtual machine execution in hardware or in a virtual machine monitor

Methods and systems for operating automotive computing devices are described. In one embodiment, a small amount of static RAM (SRAM) is incorporated into an automotive computing device. The SRAM is battery-backed to provide a non-volatile memory space in which critical data, e.g. the object store, can be maintained in the event of a power loss. Circuitry is provided to ensure that the SRAM receives back up power from the battery at appropriate times. Software manages the SRAM and the other storage assembly components and makes use of virtual paging or virtual addressing techniques to keep track of where various pages, including object store pages, are stored in the system. The software knows where all of the object store pages are located so that in the event of a power loss, the page locations are known and hence the pages can be used when power is restored. The SRAM is advantageously used to maintain so-called “dirty pages” or pages that have been written to so that these pages are not lost in the event of a power interruption. Additionally, the software can also provide an orderly means by which pages in the SRAM can be written out to flash memory thereby avoiding unnecessary flash write operations which, in turn, increases the lifetime of the flash memory.

Software management systems and methods for automotive computing devices

Methods and systems for operating automotive computing devices are described. In one embodiment, a small amount of static RAM (SRAM) is incorporated into an automotive computing device. The SRAM is battery-backed to provide a non-volatile memory space in which critical data can be maintained in the event of a power loss. Circuitry is provided to ensure that the SRAM receives back up power from the battery at the appropriate time. Software manages the SRAM and the other storage assembly components and makes use of virtual paging or virtual addressing techniques to keep track of where various pages, including object store pages, are stored in the system. The software knows exactly where all of the object store pages are stored so that in the event of a power loss, the page locations are known and hence the pages can be used when power is restored.

Automotive computing devices with emergency power shut down capabilities

A system and method are disclosed for executing, in a multitasking operating system, an application program that accesses a protected resource directly without mediation by the operating system. For example, the application can be a backup application and the resource can be a floppy disk drive, QIC tape drive, or other storage device. The method of the invention can be executed in a computer system having a processor, a storage device, and a device control mechanism for controlling operations of the storage device responsively to commands issued by the processor. The device control mechanism can be, for example, a floppy disk controller chip if the storage device is, for example, a floppy disk drive. According to the invention, the processor executes the application program as a task of the operating system. The operating system includes a software component, such as a device driver, for issuing commands to the device control mechanism. The application program has its own component for issuing commands to the device control mechanism. While the application program is executing, the operating system's command-issuing component is temporarily bypassed, and the application program's command-issuing component is used to issue a command to the device control mechanism, which controls an operation of the storage device responsively to the issued command.

Providing application programs with unmediated access to a contested hardware resource

A method and system for caching data that improve the efficiency of a cache are provided. Generally, three types of data are stored in a cache constructed according to the principles of the present invention. These types of data include: (1) path tables, (2) directories, and (3) files. Path tables include data regarding all of the directories on a storage medium, directories include data regarding all of the subdirectories and files in each directory, and files include the actual file data. The preferred embodiment of the cache logically includes eight regions. These regions include (in order of preferred descending priority): (1) path table, (2) directory, (3) two-access, (4) zero-access or prefetch, (5) sequential-locked, (6) one-access, (7) discarded, and (8) invalid. The path table region includes sectors containing path table data, the directory region includes sectors containing directory data, the two-access region includes sectors containing file data that have been accessed twice, the prefetch region includes sectors containing file data that have been prefetched, the sequential-locked region includes sectors containing file data that were prefetched and have now been locked for access, the one-access region includes sectors containing file data that have been accessed once, the discarded region includes empty sectors that are available for reuse, and the invalid region includes a single dummy sector that is used as a placeholder. During operation, a cache manager manages the cache. The cache manager is responsible for manipulating the cache, such as by adding and removing sectors to and from the cache.

Method and system for caching data

In one aspect, the present disclosure describes a process for maintaining file allocation tables (FATs) for a volume of storage medium. The process includes triggering, by a write operation, modification of data in an existing sector of a data file by writing of data to a new sector of the storage medium. The process also includes writing revised used/unused sector information into one FAT and setting a variable indicative of a number of FATs (NOF) to a first value. The process additionally includes copying the one FAT to another FAT and re-setting the variable to a second value.

Ronald Otto Radko

Papers

Software management systems and methods for automotive computing devices

Automotive computing devices with emergency power shut down capabilities

Providing application programs with unmediated access to a contested hardware resource

Method and system for caching data

Transaction-Safe FAT Files System