Heterogeneous Process Migration is a technique whereby an active process is moved from one machine to another. It must then continue normal execution and communication. The source and destination processors can have a different architecture, that is, different instruction sets and data formats. Because of this heterogeneity, the entire process memory image must be translated during the migration. "Tui" is a migration system that is able to translate the memory image of a program (written in ANSI-C) between four common architectures (m68000, SPARC, i486 and PowerPC). This requires detailed knowledge of all data types and variables used with the program. This is not always possible in non-type-safe (but popular) languages such as ANSI-C, Pascal and Fortran. The important features of the Tui algorithm are discussed in great detail. This includes the method by which a program's entire set of data values can be located, and eventually reconstructed on the target processor. Perfo...

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Current RPC mechanisms for persistent languages are either pass by reference --- in which case they do not scale --- or pass by copy --- in which case they duplicate objects and destroy sharing relationships. In this paper we argue that to build very large distributed persistent applications a compromise between these two mechanisms is needed. The ultimate goal of our research is to build a scalable persistent RPC while still maintainingobject sharing, type safety, type completeness and semantics that are readily understood by application programmers. 1 Introduction This research concerns the construction and maintenance of long-lived, large-scale, persistent applications that store and manipulate large quantities of complex inter-related data. An example is a health-care information system managing data for hospitals, patients and doctors, and their relationships with funding and regulatory agencies. These applications can be characterised by two attributes. Persistence. They need t...

Communicating complex data structures, that is those containing pointers, across machines is a common problem in distributed and parallel computing; particularly with the current move towards object-oriented programming. Some techniques utilise dedicated hardware and system software to efficiently achieve this. This paper presents a study of several software techniques for the communication of complex data structures. A selection of packing/unpacking techniques are tried and compared; in addition a mini-heap ADT, requiring no packing or unpacking, is studied. 1 Introduction Parallel computing is currently a hot topic in computing. The basic driving force of parallel computing is the desire and prospect for increased performance over conventional sequential computing. Of particular interest to us is network based parallel computing and the idea of creating a virtual supercomputer from networks of idle workstations [3]. Over the past decade the development of parallel computing has shif...

Two new facilities for Haskell are described: compression of data values in memory, and a new scheme for binary I/O. These facilities, although they can be used individually, can also be combined because they use the same binary representations for values. Heap compression in memory is valuable because it enables programs to run on smaller machines, or conversely allows programs to store more data in the same amount of memory. Binary I/O is valuable because it makes the file storage and retrieval of heap data structures smooth and painless. The combination of heap compression and binary I/O allows data transfer to be both fast and space-efficient. All the facilities described have been implemented in a variant of Rojemo's nhc compiler. Example applications are demonstrated, with performance results for space and speed. 1 Introduction 1.1 Data representation Implementors of lazy functional languages tend to use an internal representation of data which is uniform, based on graphs of ...