A technique for representing programs abstractly and independently of the eventual target architecture is presented that yields a file representation twice as compact as machine code for a CISC processor. It forms the basis of an implementation, in which the process of code generation is deferred until the time of loading. At that point, native code is created on_the_fly by a code_generating loader. The process of loading with dynamic code_generation is so fast that it requires little more time than the input of equivalent native code from a disk storage medium. This is predominantly due to the compactness of the abstract program representation, which allows to counterbalance the ad...

. A machine_independent abstract program representation is presented that is twice as compact as machine code for a CISC processor. It forms the basis of an implementation, in which the process of code generation is deferred until the time of loading. Separate compilation of program modules with type_safe interfaces, and dynamic loading (with code generation) on a per_module basis are both supported. To users of the implemented system, working with modules in the abstract representation is as convenient as working with native object_files, although it leads to several new capabilities. The combination of portability with practicality denotes a step toward a software component industry. 1. Introduction The rapid evolution of hardware technology is constantly influencing software development, for better as well as for worse. On the downside, faster hardware can conceal the complexity and cost of badly_designed programs; Reiser [Rei89] is not far off the mark in observing that s...

: We are building an infrastructure for the platform-independent distribution and execution of high-performance mobile code as a future Internet technology to complement and perhaps eventually succeed Java. Key to our architecture is a representation for mobile code that is based on adaptive compression of syntax trees. Not only is this representation more than twice as dense as Java byte-codes, but it also encodes semantic information on a much higher level. Unlike linear abstract-machine representations such as p-code and Java byte-codes, our format preserves structural information that is directly beneficial for advanced code optimizations. Our architecture provides fast on-the-fly native-code generation at load time. To increase performance further, a low-priority compilation thread continually re-optimizes the already executing software base in the background. Since this is strictly a re-compilation of already existing code, and since it occurs completely in the backgro...

At first sight, Java's position as the de-facto standard for portable software distributed across the Internet seems virtually unassailable. Interestingly enough, however, it is surprisingly simple to provide alternatives to the Java platform, using the plug-in mechanism supported by the major commercial World Wide Web browsers. We are currently developing a comprehensive infrastructure for mobile software components. This is a long-term research activity and not directly related to Java and the World Wide Web. However, purely as a technology demonstration, we have recently started a small spin-off project called "Juice" with the intent of extending our experimental mobile-code platform into the realm of the commercial Internet. Juice is implemented in the form of a browser plug-in that generates native code on-the-fly. Although our software distribution format and run-time architecture are fundamentally different from Java's, once that the appropriate Juice plug-in has been installed ...

At first sight, Java's position as the de-facto standard for portable software distributed across the Internet seems virtually unassailable. Interestingly enough, however, it is surprisingly simple to provide alternatives to the Java platform, using the plug-in mechanism supported by the major commercial World Wide Web browsers. We are currently developing a comprehensive infrastructure for mobile software components. This is a long-term research activity and not directly related to Java and the World Wide Web. However, purely as a technology demonstration, we have recently started a small spin-off project called "Juice" with the intent of extending our experimental mobile-code platform into the realm of the commercial Internet. Juice is implemented in the form of a browser plug-in that generates native code on-the-fly. Although our software distribution format and run-time architecture are fundamentally different from Java's, once that the appropriate Juice plug-in has been installe...

Over the past decade, since Java was first introduced and integrated into the Netscape web browser, several intermediate representations have been developed that might be potentially used for mobile code applications. This paper examines the requirements for a mobile code representation, presents several examples of stack-based, tree-oriented, and proof-annotating mobile code representations, and evaluates each of these representations according to the requirements. Povzetek: Članek podaja pregled mobilnih kod. 1