Abstract: An indicator is provided in a Page Frame Table Entry to identify a page frame as “Permanently Non-Preferred” (PNP). The indicator is set for page frames in storage subincrements which have locations corresponding to page frames determined to be “bad” (permanent errors) during system IPL, when reconfiguring storage on-line, or when a storage-related error occurs for such a frame during system execution. Mechanisms are provided to convert even PNP page frames to preferred status when shortages of preferred pages exist; but the mechanism used for choosing PNP frames, and for determining which PNP frames to convert to preferred status when conversion is needed, increase the likelihood of locating a target subincrement to use in copying pages from a preferred storage subincrement when the preferred storage is taken off-line.

Abstract: In an object-oriented run-time environment, inheritance and disinheritance of methods and data to and from an object is facilitated. When an object is invoked, a method within the object is called. Execution of this method may, however, not be possible because, e.g., a data type passed to the method may not be supported thereby. In response to this condition, the object invokes a process that inherits a required method and/or datum into the object. For example, a method that does support the previously unsupported data type may be inherited. After inheritance is completed, the object is reinvoked with the previously unsupported data type. Processing may then continue using the inherited method. After the inherited method is no longer needed, it may be disinherited from the object.

Abstract: A recovery mechanism enabling recovery to be performed along logical execution paths of tasks processing within a computer system. Tasks executing within the computer system invoke one another in a logical invocation sequence. The recovery mechanism allows a task to initiate recovery for another task, such that recovery follows the logical sequence of events. The recovery mechanism is applicable to procedural, as well as object-oriented systems, and is usable with homogeneous and heterogeneous systems.

Abstract: Apparatus for protecting memory storage blocks (page frames) against unwanted I/O accesses, including I/O data transferred in an unwanted direction. I/O storage keys are provided in an I/O protection array. Each I/O key is comprised of one or two bits and is associated with a respective storage block in computer memory. If the array contains two bit I/O keys, each key has 4 settings for controlling I/O accesses to an associated storage block; which: 1) inhibit an I/O access in the input direction of I/O data flow, 2) inhibit an I/O access in the output direction of I/O data flow, 3) allow I/O accesses in both directions, or 4) prevent all I/O accesses. If the array contains single bit I/O storage keys, each key has two settings, which: 1) prevent all I/O accesses in the associated storage block, or 2) allow all I/O accesses in the associated block. No I/O program keys are needed for controlling this type of I/O protection, which avoids key comparison operations by the I/O access protection apparatus.

Abstract: A method and system are provided for executing a service processor request within a data processing system having one or more processors within a central processing complex, each of the processors within the central processing complex including allocatable processor resources. Each of the processors within the central processing complex is provided with the capability of processing selected service processor requests by reserving a portion of the allocatable processor resources within each of the processors for such purpose. A service processor request within the central processing complex is initially processed utilizing at least one of the processors in response to receiving a service processor request, if sufficient processor resources are available to process the service processor request within the reserved portion of the allocatable resources.

Abstract: I/O protection key processes for protecting storage blocks (page frames) in a shared main storage against unwanted I/O accesses. Independent CP (central processor) key protection may optionally be provided to protect the same storage against unwanted CP accesses. Processes are included for initializing, and addressing I/O buffers used by the I/O programs; each I/O buffer is comprised of a contiguous set of the blocks (page frames). The I/O keys may be used independently of any CP keys provided for protecting the same blocks against unwanted accesses by any CP in the system. The I/O keys must be supported by a hardware I/O storage array when only real (or absolute) addressing is used by I/O programs. However, the CP keys may be supported by either real CP keys in a second hardware key array; or alternatively the CP keys may be provided as virtual CP keys in a field in each page table entry (which is used for translating CP virtual addresses to CP real addresses).

Abstract: Protection against unwanted I/O accesses in main storage blocks/page frames independent of any storage protection provided against unwanted CPU accesses. An I/O protection array is used containing one-bit I/O keys used only for protecting which respectively protect associated blocks/page frames from unwanted accesses by I/O programs. Each one-bit I/O key is used to allow or disallow I/O accesses into an associated storage block. Any CPU access is not affected by the I/O storage key. No I/O program key is used and therefore no key compare operation is required. However, the embodiment is compatible with use of CPU storage protection using CPU storage keys in either real form in a CPU storage key array, or in virtual form in page table entries without using any CPU storage key array.

Abstract: Main storage access protection against unwanted I/O accesses in storage blocks/page frames independent of any protection provided against unwanted CPU accesses. I/O programs are each assigned an I/O program key which is matched against an I/O storage key selected from an I/O storage protection array used only for protecting blocks from accesses by I/O programs, but not from any accesses by CPU programs. The address of each storage access request by an I/O program selects a key entry in the array containing the I/O storage key used in the comparison with the I/O program key. Each entry in the I/O storage array may also contain a second I/O storage key which may be either a one-bit type as described and claimed in application Ser. No. 08/652,197 or a two-bit type as described and claimed in application Ser. No. 08/652,079, both applications of which were filed on the same day as this application and assigned to the same assignee.

Abstract: A dynamic reconfiguration request for a change in a system's physical configuration is transmitted from a configuration controller to a hypervisor controlling operating systems executing in one or more partitions of the system. The hypervisor translates the physical reconfiguration request into a request for reconfiguration of logical resources known to the operating systems, first verifying it against an installation policy, and passes the requests to the operating systems in the partitions. The operating systems perform logical reconfiguration, then request physical reconfiguration of the hypervisor. The hypervisor initiates the physical reconfiguration through the configuration controller.

Abstract: In a data processing system, a hardware system area ("HSA") storage is associated with the hardware configuration of the system. A change in the system hardware configuration typically corresponds to a change in HSA size. Upon determination of the requirement for, for example, increasing the size of HSA, a region of storage is freed from use as central storage or expanded storage. The freed region is incorporated into the data processing system as HSA storage. The process may be reversed to reduce the size of HSA by converting a region of HSA into either central storage or expanded storage.

Abstract: A method and system are provided for executing a service processor request within a data processing system having one or more processors within a central processing complex, each of the processors within the central processing complex including allocatable processor resources. Each of the processors within the central processing complex is provided with the capability of processing selected service processor requests by reserving a portion of the allocatable processor resources within each of the processors for such purpose. A service processor request within the central processing complex is initially processed utilizing at least one of the processors in response to receiving a service processor request, if sufficient processor resources are available to process the service processor request within the reserved portion of the allocatable resources.

Abstract: In a computer system, a computer program is provided having multiple sections. First and second sections of the computer program correspond to different execution environments. Each of the first section and second section is automatically compiled for its corresponding execution environment. Further, the multiple sections of the computer program may call each other via intra-program type procedure calls. These intra-program type procedure calls are automatically translated into inter-execution environment type procedure calls, between the sections, for their respective execution environments.

Abstract: The amount of real memory space used by descriptor tables of a computer system is reduced. On system initialization, sufficient contiguous virtual memory space for each table is allotted for descriptors in the tables to define all memory space in both central storage and expanded storage. However, only descriptors for on-line storage locations, relative to a particular partition, are placed in these tables. As the system operates, the tables are continuously updated, removing descriptors for storage locations taken off-line and adding descriptors for blocks of memory brought on-line so that the tables reflect only the storage locations then on-line in the particular partition.

Abstract: Techniques are presented for efficiently transferring computer code from a source computer to a target computer for execution on the target computer. A virtual memory space for the computer code is created on the target computer. The computer code is linked on the source computer such that addressing of the resulting executable version of the computer code corresponds to the allocated virtual memory space on the target computer. The executable computer code is then stored in the memory of the source computer. As the target computer executes the computer code, page faults result because its allocated virtual memory space is empty. The memory pages required to remediate the page faults are obtained from the source computer on an on-demand basis. Execution accordingly proceeds.

Abstract: In an object-oriented computer system having multiple execution environments, a source code of a computer program is provided having multiple classes therein. The classes have affinities for execution environment type characteristics defined therewith. For each class, an execution environments is determined that satisfies the affinities of the class, and the class is compiled for the determined execution environment. As examples, affinities may include those directed toward processors, operating systems, user interfaces and software resources.

Abstract: A method and system are provided for executing a service processor request within a data processing system having one or more processors within a central processing complex, each of the processors within the central processing complex including allocatable processor resources. Each of the processors within the central processing complex is provided with the capability of processing selected service processor requests by reserving a portion of the allocatable processor resources within each of the processors for such purpose. A service processor request within the central processing complex is initially processed utilizing at least one of the processors in response to receiving a service processor request, if sufficient processor resources are available to process the service processor request within the reserved portion of the allocatable resources.

Abstract: In an object-oriented run-time environment, inheritance and disinheritance of methods and data to and from an object is facilitated. When an object is invoked, a method within the object is called. Execution of this method may, however, not be possible because, e.g., a data type passed to the method may not be supported thereby. In response to this condition, the object invokes a process that inherits a required method and/or datum into the object. For example, a method that does support the previously unsupported data type may be inherited. After inheritance is completed, the object is reinvoked with the previously unsupported data type. Processing may then continue using the inherited method. After the inherited method is no longer needed, it may be disinherited from the object.

Abstract: A program stored on a portable storage medium for transferring the program from/to a data processing system, including to or from a disk medium in the system. The program manages I/O buffers that use I/O storage protection key for protecting storage blocks (page frames) in a shared main storage against unwanted I/O accesses, but the I/O storage keys do not protect the storage blocks from an CP (central processor) accesses. CP key protection may optionally be provided to independently protect the same storage block against unwanted CP accesses. Processes initialize, and address I/O buffers used by I/O programs; each I/O buffer is comprised of a contiguous set of the blocks (page frames). The I/O keys are used independently of any CP keys, and both I/O and CP keys are required for protecting any block against unwanted accesses by both I/O and CP accesses. The I/O keys are supported by a hardware I/O storage key array when real (or absolute) addressing is used by I/O the programs.

Abstract: A dynamic reconfiguration request for a change in a system's physical configuration is transmitted from a configuration controller to a hypervisor controlling operating systems executing in one or more partitions of the system. The hypervisor translates the physical reconfiguration request into a request for reconfiguration of logical resources known to the operating systems, first verifying it against an installation policy, and passes the requests to the operating systems in the partitions. The operating systems perform logical reconfiguration, then request physical reconfiguration of the hypervisor. The hypervisor initiates the physical reconfiguration through the configuration controller.