Digital Equipment Corporation

Frank L Perazzoli, Sr

David N Cutler

James W Kelly

An object based operating system for a multitasking computer system provides objects which represent the architecture or interrelationships of the system's resources. Access to certain objects is required in order to use corresponding resources in the system. All objects have a consistent data structure, and a consistent method of defining the operations which apply to each type of object. As a result, it is relatively easy to add new types of system objects to the operating system. Waitable objects are used to synchronize the operation of one or more processes with one another or with specified events. The system provides routines for generating new types of waitable objects, and thereby generating a modified operating system, without modifying other aspects of the operating system's kernel.

System and method for adding new waitable object types to object

An object based operating system for a multitasking computer system provides objects which represent the architecture or interrelationships of the system's resources. Access to certain objects is required in order to use corresponding resources in the system. All objects have a consistent data structure, and a consistent method of defining the operations which apply to each type of object. As a result, it is relatively easy to add new types of system objects to the operating system. The object based operating system supports multiple levels of visibility, allowing objects to be operated on only by processes with the object's range of visibility. This allows objects to be made private to a process, shared by all processes within a job, or visible to all processes within the system. An object or an entire set of objects can be moved to a higher visibility level when objects need to be shared. In addition, access to each object is controlled through an access control list which specifies the processes authorized to access the object, and the types of access that are allowed. An object with a restricted access control list can be associated with a 'privileged operation', thereby restricting use of the privileged operation to those user processes authorized to access the corresponding object. Waitable objects are used to synchronize the operation of one or more processes with one another or with specified events. The system provides routines for generating new types of waitable objects without modifying the operating system's kernel.

Object transferring system and method in an object based computer

Temporary object handling system and method in an object based computer

An object based operating system for a multitasking computer system provides objects which represent the architecture or interrelationships of the systems's resources. Access to certain objects is required in order to use corresponding resources in the system. All objects have a consistent data structure, and a consistent method of defining the operations which apply to each type of object. As a result it is relatively easy to add new types of system objects to the operating system. The object based operating system supports multiple levels of visibility, allowing objects to be operated on only by processes with the object's range of visibility. This allows objects to be made private to a process, shared by all processes within a job, or visible to all processes within the system. An object or an enitre set of objects can be moved to a higher visibility level when objects need to be shared. In addition, access to each object is controlled through an access control list which specifies the processes authorized to access the object, and the types of access that are allowed. An object with a restricted access control list can be associated with a 'privileged operation', thereby restricting use of the privileged operation to those user processes authorized to access the corresponding object. Waitable objects are used to synchronize the operation of one or more processes with one another or with specified events. The system provides routines for generating new types of waitable objects without modifying the operating system's kernel.

Conditional object creating system having different object pointers for

An object based operating system for a multitasking computer system provides objects which represent the architecture or interrelationships of the systems's resources. Access to certain objects is required in order to use corresponding resources in the system. All objects have a consistent data structure, and a consistent method of defining the operations which apply to each type of object. As a result, it is relatively easy to add new types of system objects to the operating system. The object based operating system supports multiple levels of visibility, allowing objects to be operated on only by processes with the object's range of visibility. This allows objects to be made private to a process, shared by all processes within a job, or visible to all processes within the system. An object or an entire set of objects can be moved to a higher visibility level when objects need to be shared. In addition, access to each object is controlled through an access control list which specifies the processes authorized to access the object, and the types of access that are allowed. An object with a restricted access control list can be associated with a 'privileged operation', thereby restricting use of the privileged operation to those user processes authorized to access the corresponding object. Waitable objects are used to synchronize the operation of one or more processes with one another or with specified events. The system provides routines for generating new types of waitable objects without modifying the operating system's kernel.

Object container transfer system and method in an object based computer

A virtual memory management system and method in which the mechanism for swapping in pages of memory in secondary storage replaces the overhead of retrieving pages from secondary storage by swapping logically contiguous clusters of pages each time that a page from secondary memory is needed. To improve the efficiency of in-page clustering, the size of the clusters which are read in are heuristically adjusted. Clustered pages are not entered into the working set until they are accessed by the process. Instead, the cluster of pages read in from secondary memory are initially entered a 'standby list' of pages which are more eligible for reallocation than pages in the working set of the process. If the process does not access a particular cluster page within a relatively short period of time of its entry onto the standby list it is reallocated by the system's memory manager. In this way, in-page cluster pages do not replace potentially more valuable pages in the working set until those pages are actually requested by the process. Depending on whether the cluster pages are used before being reallocated, cluster sizes in corresponding portions of the virtual memory space are increased or decreased.

Virtual memory paging apparatus with variable size in-page clusters

A virtual memory nmanagement system and method in which the mechanism for selecting the pages to be swapped out of a process's working set takes into account special criteria for swapping out page table pages. When all the virtual memory pages referenced by a page table page are invalid, but some remain stored in primary memory, the page table page becomes eligible for removal from the process's working set. A page table page is made eligible for being swapped out to secondary memory only when every virtual memory page referenced by that page table page is invalid and no longer stored in primary memory.

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Redmond, WA, United States of America

Frank L Perazzoli, Sr