Abstract: A method of scheduling tasks subject to timing and succession constraints essentially comprises grouping the tasks in layers according to succession constraints and scheduling the tasks layer by layer in increasing layer order up to the last layer, if possible, and then deciding that the resulting scheduling succeeds. If the scheduling achieved in a layer other than the first layer does not satisfy one or more constraints applying to a task belonging to the current layer, the method reschedules a layer containing a predecessor task corresponding to an unsatisfied constraint, schedules or reschedules all the other layers higher than the layer of the predecessor task, up to the last layer, if possible, and then decides that the resulting scheduling succeeds. Applications include scheduling of transmission of information on an industrial data bus.

Abstract: An apparatus and method for implementation in a computing system (5) which allows the transfer of control from one process (10) to another process (40). The input/output supervisor (20) and a newly provided control mechanism (50) are used to switch control. Transfer of data between the two processes is carried out using a data pool (75). This data pool (75) is accessible to both processes (10, 40) through the control mechanism (50).

Abstract: A method and apparatus for generating patching resources in an information processing system having operating instructions on a Read Only Memory Device. The present invention simplifies the patch generation and installation processes. A patch resource is generated and used by a patch installation process. Patch resources are generated for each ROM version by comparing previous ROM versions to the new ROM version. A patch resource is comprised of a plurality of entries, each of which defines a vector table address, an offset into the vector table and the routine to be inserted. By comparing routines between the ROM versions, routines which are different or new are identified. These routines will become patch resource entries. For patch installation, the ROM version number for the installed ROM is determined; the proper patching resource is retrieved, and the patch resource entries cause the patches to be installed.

Abstract: A computer-implemented method, computer system, and memory for performing a fork operation of a parent process is provided. The parent process includes one or more threads, each having a kernel stack. The method includes the steps of locating the kernel stacks in a first memory location (e.g., segment 1) if the parent process is multi-threaded, in response to an initiation of a fork by a calling thread, switching the kernel stack of the calling thread to a second memory location if the parent process is multi-threaded, and copying the second memory location (e.g., segment 2) to create a child process.

Abstract: A method of individually isolating a circuit board that has been added to an expansion slot of a computer system. If a conflict exists between the circuit board and other resources of the computer system, the present invention isolates the memory resource requirements of the circuit board from the computer system. The memory resources requirements of the circuit board may be isolated from the computer system by disabling access to the memory of the computer system which is generally designated for circuit board use. Access to this memory may be disabled by disabling an address line of the expansion slot in which the circuit board has been added. In a computer system utilizing an industry standard bus system the present invention disables address A19 of the expansion slot.

Abstract: A resource assignment apparatus for use with a software compiler or translator for compiling or translating a high-level source program into a machine language program, wherein the resource assignment apparatus assigns the variables in the high-level source program to system resources consisting of registers, memory, and the like. The resource assignment apparatus generates assignments consisting of the variables and their live ranges and finds the interference cost incurred when assigning these various assignments to each of the various resources, consisting of data registers, address registers, memory, and the like. The apparatus sorts the assignments into groups whereby these interference costs will be the lowest. The resource element minority assignment unit then carries out the assigning of each of these groups of sorted assignment. The various assignments with live ranges which interfere are assigned to different resource elements.

Abstract: U2G is a software tool that runs on the GCOS-8 operating system and enables it recognize and process the commonly used commands of the UNIX operating system. U2G is a UNIX-GCOS-8 translator that enables the GCOS-8 to recognize, accept and execute UNIX commands. Thus, it enables the UNIX users to work with the GCOS-8 system without prior training. U2G can translate the most commonly used UNIX commands along with their respective options into equivalent GCOS-8 Time Sharing System (TSS) commands. U2G can be used with a "Verbose" mode option which serves to provide descriptive information about the commands and the translation process. U2G has on-line help screens and "explain" pages for all of the important concepts and equivalences. U2G enhances the capabilities of GCOS-8 by supporting the important UNIX concept of "aliasing" and the use of shell variables. Another enhancement to GCOS-8 is support for I/O redirection and simple command procedures.

Abstract: U2G is a software tool that runs on the GCOS-8 operating system and enables it recognize and process the commonly used commands of the UNIX operating system. U2G is a UNIX-GCOS-8 translator that enables the GCOS-8 to recognize, accept and execute UNIX commands. Thus, it enables the UNIX users to work with the GCOS-8 system without prior training. U2G can translate the most commonly used UNIX commands along with their respective options into equivalent GCOS-8 Time Sharing System (TSS) commands. U2G can be used with a "verbose" mode option which serves to provide descriptive information about the commands and the translation process. The verbose mode is disabled by a "terse" command.

Abstract: The present invention provides a verifier for use in conjunction with programs utilizing data type specific bytecodes for verifying the proper operation of the executable program prior to actual execution by a host processor. A verifier is provided which includes a virtual stack for temporarily storing stack information which parallels the typical stack operations required during the execution a bytecode program. The verifier also includes a stack snapshot storage structure having a snapshot directory and stack snapshot storage area for storing the state of the virtual stack at various points during program verification so as to assure proper stack manipulations by the source program. A two step source program verification process is provided for in which the source program is initially loaded into the verifier and a first pass source program evaluation is performed.

Abstract: A method and system is described which allows execution overlap in a computer having a plurality of processing elements. The method and system provide an accumulation schedule based on the expected completion times of the processing elements. Outputs from the processing elements are accumulated according to the accumulation schedule. The accumulation schedule includes a plurality of accumulation flags which indicate when the outputs are to be accumulated.

Abstract: Multi-user system includes a server connected to one or more workstations or "clients" through a computer network. System provides concurrent access to shared resources (e.g., common data structures residing on the server), but without the disadvantage attendant with conventional mutual exclusive (mutex) primitives. Specifically, the system provides a "nested mutex" mechanism, so that user program code can acquire and release mutexes without concern for deadlocking and without special processing for testing a particular mutex condition or state. At the same time, the system prevents other threads or processes from accessing the shared resource in a manner which would violate concurrency.

Abstract: U2G is a software tool that runs on the GCOS-8 operating system and enables it recognize and process the commonly used commands of the UNIX operating system. U2G is a UNIX-GCOS-8 translator that enables the GCOS-8 to recognize, accept and execute UNIX commands. Thus, it enables the UNIX users to work with the GCOS-8 system without prior training. U2G can translate the most commonly used UNIX commands along with their respective options into equivalent GCOS-8 Time Sharing System (TSS) commands. U2G can be used with a "Verbose" mode option which serves to provide descriptive information about the commands and the translation process. U2G has on-line help screens and "explain" pages for all of the important concepts and equivalences. U2G enhances the capabilities of GCOS-8 by supporting the important UNIX concept of "aliasing" and the use of shell variables.

Abstract: U2G is a software tool that runs on the GCOS-8 operating system and enables it recognize and process the commonly used commands of the UNIX operating system. U2G is a UNIX-GCOS-8 translator that enables the GCOS-8 to recognize, accept and execute UNIX commands. Thus, it enables the UNIX users to work with the GCOS-8 system without prior training. U2G can translate the most commonly used UNIX commands along with their respective options into equivalent GCOS-8 Time Sharing System (TSS) commands. U2G can be used with a "Verbose" mode option which serves to provide descriptive information about the commands and the translation process. U2G has on-line help screens and "explain" pages for all of the important concepts and equivalences. U2G enhances the capabilities of GCOS-8 by supporting the important UNIX concept of "aliasing" and the use of shell variables. Further, the UNIX "piping" feature is made available to GCOS-8.