The Distributed Real-Time Specification for Java: A Status Report
This paper is a status report as of December 2001 on the Distributed Real-Time Specification for Java (DRTSJ), being developed by the JSR-50 Expert Group in Sun's Java Community Process; the presentation in March 2002 will be current as of that date. The paper first summarizes what "real-time," "distributed," and "distributed real-time" mean in the context of the DRTSJ, since those terms are commonly used in widely different ways. The DRTSJ is focused on supporting predictability of end-to-end timeliness for sequentially trans-node behaviors (e.g., chains of invocations) in dynamic distributed object systems. The DRTSJ introduces the Distributed Real-Time Remote Method Invocation (RMI) model, based on the Alpha distributed real-time OS kernel's distributed threads model. The OMG Real-Time CORBA 2.0 (dynamic scheduling) specification also employs a distributed threads model, so these two distributed real-time computing system programming model standards are relatively congruent. The DRTSJ consists of extensions to the Real-Time Specification for Java (RTSJ), Java's RMI, and the RTSJ Java Virtual Machine. The DRTSJ, including the reference implementation, is expected to be released by the end of 2002.