Abstract: Apparatus and processes, including computer implemented processes, for managing exceptions throwable during execution of methods in one or more classes by a machine. Each method includes an exception handler array defining exception handlers associated with the method. The method includes combining the exception handler arrays for all methods into a single exception handler table.

Abstract: A system links architecture neutral code downloaded to a resource constrained computer. The code may be separated into one or more packages having one or more referenceable items. The system maps the one or more referenceable items into corresponding one or more tokens; orders the tokens to correspond to a run-time mode; downloads the packages to the resource constrained computer; and links the packages into an executable code using the ordered tokens.

Abstract: A method for arithmetic expression optimization includes receiving a first instruction defined for a first processor having a first base, the first instruction including an operator and at least one operand, converting the first instruction to a second instruction optimized for a second processor having a second base when all operands do not carry potential overflow or when the operator is insensitive to overflow, the second base being smaller than the first base, and converting to a wider base a third instruction that is the source of the overflow when the at least one operand the potential for overflow and when the operator is sensitive to overflow.

Abstract: A method of operating a computer system includes providing a program in memory, verifying the program prior to an installation of the program and generating a program fault signal when the verification fails. The program includes at least one program unit, and each program unit includes an Application Programming Interface (API) definition file and an implementation. Each API definition file defines items in its associated program unit that are made accessible to one or more other program units and each implementation includes executable code corresponding to the API definition file. The executable code includes type specific instructions and data. Verification includes determining whether a first program unit implementation is internally consistent, determining whether the first program unit implementation is consistent with a first program unit API definition file associated with the first program unit implementation and generating a program fault signal when the verifying fails.

Abstract: A resource-constrained device such as a smart card or the like includes memory for storing an application software program comprising an object-oriented, verifiable, platform-independent, type-safe and pointer-safe sequence of instructions. The device can also include a virtual machine implemented on a microprocessor where the virtual machine is capable of executing the sequence of instructions. Each instruction includes an operation code, and each data manipulation instruction is specific to a particular data type. The application program can be stored on a computer-readable medium prior to being received by the resource-constrained device. Methods of using such an application program, including accessing the program over the Internet and downloading it to a smart card, also are disclosed.

Abstract: A method for representing an application programming interface (API) for an object-oriented library includes creating a list of public elements in the library and storing the list. Each public element in the list includes a sublist of all public related elements for the element. According to one aspect, the public elements include classes and interfaces, the public related elements include public superclasses and public superinterfaces, and the library is a Java™ package. According to one aspect, a method for determining a program hierarchy includes receiving an API definition file for an object-oriented library and indicating a first public element is a direct parent of a second public element when the first public element is represented in the sublist for the second public element and the first public element is not represented in the sublist for any other public element listed in the sublist for the second public element.

Abstract: A method of operating a computer system includes providing a first version of a program in memory and verifying the program prior to program execution. Program verification includes indicating a verification error when a first version of a first program unit implementation is not internally consistent, indicating a verification error when the first version of the first program unit implementation is inconsistent with the version of the program unit API definition file associated with the first version of the first program unit implementation, receiving a second version of the first program unit implementation and a second version of the first program unit implementation is binary compatible with the first version of the first program unit implementation by comparing the first version of the first program unit API definition file and the second version of the first program unit API definition unit.

Abstract: Remote incremental program verification may be achieved by receiving content verified by at least one content provider, installing the content on a resource-constrained device, issuing the resource-constrained device to an end user, and allowing post-issuance installation of verified content on the resource-constrained device by a trusted post-issuance installer. The at least one content provider includes an applet provider, a device manufacturer, a device issuer, and a trusted post-issuance installer. The content includes at least one program unit, where each program unit comprises an Application Programming Interface (API) definition file and an implementation. Each API definition file defines items in its associated program unit that are made accessible to one or more other program units, and each implementation includes executable code corresponding to the API definition file. The executable code includes type-specific instructions and data.

Abstract: Remote incremental program verification may be achieved by receiving content verified by at least one content provider, installing the content on a resource-constrained device, disabling subsequent installation of content on the resource-constrained device, and issuing the resource-constrained device to an end user. The at least one content provider includes an applet provider, a device manufacturer, and a device issuer. The content includes at least one program unit, where each program unit comprises an Application Programming Interface (API) definition file and an implementation. Each API definition file defines items in its associated program unit that are made accessible to one or more other program units, and each implementation includes executable code corresponding to the API definition file. The executable code includes type specific instructions and data.

Abstract: A system links architecture neutral code downloaded to a resource constrained computer. The code may be separated into one or more packages having one or more referenceable items. The system maps the one or more referenceable items into corresponding one or more tokens; orders the tokens to correspond to a run-time mode; downloads the packages to the resource constrained computer; and links the packages into an executable code using the ordered tokens.

Abstract: Apparatus and processes, including computer implemented processes, for managing exceptions throwable during execution of methods in one or more classes by a machine. Each method includes an exception handler array defining exception handlers associated with the method. The method includes combining the exception handler arrays for all methods into a single exception handler table.

Abstract: A method of operating a computer system includes providing a program in memory, verifying the program prior to an installation of the program and generating a program fault signal when the verification fails. The program includes at least one program unit, and each program unit includes an Application Programming Interface (API) definition file and an implementation. Each API definition file defines items in its associated program unit that are made accessible to one or more other program units and each implementation includes executable code corresponding to the API definition file. The executable code includes type specific instructions and data. Verification includes determining whether a first program unit implementation is internally consistent, determining whether the first program unit implementation is consistent with a first program unit API definition file associated with the first program unit implementation and generating a program fault signal when the verifying fails.

Abstract: A method for arithmetic expression optimization includes receiving a first instruction defined for a first processor having a first base, the first instruction including an operator and at least one operand, converting the first instruction to a second instruction optimized for a second processor having a second base when all operands do not carry potential overflow or when the operator is insensitive to overflow, the second base being smaller than the first base, and converting to a wider base a third instruction that is the source of the overflow when the at least one operand the potential for overflow and when the operator is sensitive to overflow.

Abstract: A method for arithmetic expression optimization includes receiving a first instruction defined for a first processor having a first base, the first instruction including an operator and at least one operand, converting the first instruction to a second instruction optimized for a second processor having a second base when all operands do not carry potential overflow or when the operator is insensitive to overflow, the second base being smaller than the first base, and converting to a wider base a third instruction that is the source of the overflow when the at least one operand the potential for overflow and when the operator is sensitive to overflow.

Abstract: A method of operating a computer system includes providing a program in memory, verifying the program prior to an installation of the program and generating a program fault signal when the verification fails. The program includes at least one program unit, and each program unit includes an Application Programming Interface (API) definition file and an implementation. Each API definition file defines items in its associated program unit that are made accessible to one or more other program units and each implementation includes executable code corresponding to the API definition file. The executable code includes type specific instructions and data. Verification includes determining whether a first program unit implementation is internally consistent, determining whether the first program unit implementation is consistent with a first program unit API definition file associated with the first program unit implementation and generating a program fault signal when the verifying fails.

Abstract: A system links architecture neutral code downloaded to a resource constrained computer. The code may be separated into one or more packages having one or more referenceable items. The system maps the one or more referenceable items into corresponding one or more tokens; orders the tokens to correspond to a run-time mode; downloads the packages to the resource constrained computer; and links the packages into an executable code using the ordered tokens.

Abstract: A method for arithmetic expression optimization includes receiving a first instruction defined for a first processor having a first base, the first instruction including an operator and at least one operand, converting the first instruction to a second instruction optimized for a second processor having a second base when all operands do not carry potential overflow or when the operator is insensitive to overflow, the second base being smaller than the first base, and converting to a wider base a third instruction that is the source of the overflow when the at least one operand the potential for overflow and when the operator is sensitive to overflow.

Abstract: A method for arithmetic expression optimization includes receiving a first instruction defined for a first processor having a first base, the first instruction including an operator and at least one operand, converting the first instruction to a second instruction optimized for a second processor having a second base when all operands do not carry potential overflow or when the operator is insensitive to overflow, the second base being smaller than the first base, and converting to a wider base a third instruction that is the source of the overflow when the at least one operand the potential for overflow and when the operator is sensitive to overflow.

Abstract: A method for visually displaying the status of edits utilizes a plurality of visual indicia proximal the portions of edited program segments. Program segments which have not been edited and are currently part of the executable program in the programmable logic controller's processor are represented with solid power rails. Edited rungs which have either been inserted, replaced or deleted are noted as such by I, R and D indicia proximal the power rail of the rung. An asterisk symbol (*) is used to visually identify rungs that have been modified at the workstation but which have not yet been downloaded to the controller. Other visual indicia identify to a workstation operator rungs which have been verified. When the controller is put into test edits mode, the state of the program in the controller prior to downloading the edited program segments is maintained but is not executed and the edits are resolved into the program executing in the processor.