Morrison, R. & Atkinson, M.P. "Persistent Languages and Architectures" (1990) Security and Persistence, Rosenberg, J. & Keedy, J.L. (ed), Springer-Verlag pp928  Home/Search   Document Not in Database   Summary   Related Articles   Check

....it can have an effect on the functionality provided by persistence, and the ease with which this functionality may be exploited. It is generally accepted that there are a number of properties a good persistence mechanism will exhibit [Atkinson et al. 83b, Atkinson et al. 87, Agrawal et al. 89b, Morrison et al. 90] The property that is considered the most important is orthogonality of persistence to type. When a persistence mechanism has this property, values of any type may persist. The first language to incorporate fully orthogonal persistence was PS Algol [Atkinson et al. 83a] This is an imperative ....

Morrison, R. & Atkinson, M.P. "Persistent Languages and Architectures" (1990) Security and Persistence, Rosenberg, J. & Keedy, J.L. (ed), Springer-Verlag pp928

....closure of that root. Other systems have taken the approach of associating persistence with type [40, 50] in violation of the third principle (and the second as a consequence) This can result in dangling references, or at best invalidated fields of structures, as shown in Figures 1 and 2 from [43]. Database Type Database Type Value Figure 1: Persistent objects before being sent to the store. Database Type Database Type Nil Nil Figure 2: The same objects as in Figure 1 in the persistent store. Figure 1 shows a structured object containing pointers to two persistent objects and one ....

....operation results in the object shown in Figure 2. Such inconsistencies make it more difficult to build systems and result in latent errors. Systems which support persistence by reachability never have this problem and are therefore preferable. There are several advantages of persistent systems [43]. First they reduce complexity for application builders. In conventional systems the system designer must map the real world onto a combination of a programming language and a database file system. These two mappings often have complex interactions and may be somewhat incompatible. A second ....

Morrison, R. and Atkinson, M. P. "Persistent Languages and Architectures", Proceedings of the International Workshop on Computer Architectures to Support Security and Persistence of Information, Bremen, West Germany, (ed J. Rosenberg and J. L. Keedy), Springer-Verlag and the British Computer Society, pp. 9-28, 1990.

....some identifier is the same as the type of the value when it was initially bound through a bind. Our design maintains the principle of orthogonality between persistence and type [4] persistence is not a property associated with a type. We also maintain the principle of referential transparency [19]: the persistent value retrieved is the same, not a copy, of the value saved and its internal topology is preserved. In short, our design, which may change as we gain experience with our implementation, provides a singlelevel of indirection to persistent memory through a symbol table of ....

R. Morrison and M.P. Atkinson. Persistent Languages and Architectures, pages 9--28. Springer-Verlag, 1990.

....rather than shared. Others such as E [Rich89a] may result in dangling pointers if a persistent data structure is created which contains non database types. In this thesis, the term persistence will be used to mean orthogonal persistence. 1.2. 3 Advantages of Persistence Morrison and Atkinson [Morr90] describe four main advantages which are derived from persistence as follows: First, there is reduced complexity for the programmer. In non persistent systems, the programmer must manage the mapping between database management system and the programming language and the different ways in which ....

Morrison, R. and Atkinson, M.P., Persistent Languages and Architectures, in Security and Persistence, Bremen Workshop, pp928, Springer-Verlag, 1990

....may persist and that the mechanism for identifying persistent objects is independent of the type system. The advantages of persistent systems include: a reduction in complexity because of the simplified model of the world involving only programming language constructs and no database file system [16] . potential reduction in code size and execution time because there is no need to write code to flatten and rebuild data structures for storage in files [4] since all data resides in the same store a single model of protection may be used. This is in contrast to the multi level protection ....

Morrison, R. and Atkinson, M. P. "Persistent Languages and Architectures", Proceedings of the International Workshop on Computer Architectures to Support Security and Persistence of Information, (ed J. Rosenberg and J. L. Keedy), Springer-Verlag and the British Computer Society, pp. 9-28, 1990.

....type dependent or type independent. Persitence is type dependent if only objects of certain types can be made persistent. var p: Persistent Integer; Persistence is type independent if all types of objects may be made persistent; this kind of persistence is said to possess datatype orthogonality [MA90] Note that persistent objects may be scoped using this facility. User or Compiler inserted Annotations: The user or application programmer may declare persistence by using annotations indicating whether an object is persistent or otherwise. For example, declare human(body:transient, ....

R. Morrison and M.P. Atkinson. Persistent languages and architectures. In Persistence and Security, Bremen. Springer-Verlag, 1990.

....This may not always be known statically. The application of the above three principles yields orthogonal persistence. Orthogonal persistence ensures that no code need be written to deal with the transfer of data between short and long term storage explicitly. Moreover, referential integrity[Morr90] is preserved over persistent store operations sharing and topology are unaltered. This 4 is particularly important in a functional language setting from an efficiency viewpoint (semantically it should not matter) Languages such as Amber[Card83] and a proposal for persistence in ML do not ....

Morrison, R. and Atkinson, M.P., Persistent Languages and Architectures, in Security and Persistence, Bremen Workshop, pp9-28, Springer-Verlag, 1990

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