The Java programming language brings different benefits to different audiences. The article examines common perspectives on what Java offers, or ought to offer to the domain of real time programming. It is concluded that real time programming with Java technologies is a reality today. Emerging technologies will increase the breadth of options available to real time programmers who choose to build on the Java platform. Each real time technology enables slightly different benefits and exposes different risks. Real time developers should familiarize themselves with the alternative approaches before committing to a particular technology.

Operating system and real time researchers have historically worked in areas that are considered by each to be specialized and unrelated to the other's domain. However, embedded real time systems are evolving such that they now require increasing amounts of general purpose operating system support. Meanwhile, general purpose computer systems are evolving such that they are requiring increasing amounts of support for reliable real time components. These trends suggest that the real time and mainstream operating system researchers must join forces in order to effectively solve problems that are common to both. The paper provides examples of the shortcomings of current approaches to these problems, and suggests a number of areas in which these two independent research groups might work together more closely in the future.

Abstract Concurrent language features have been added to an experimental dialect of Icon called Conicon. These new language features allow Icon to deal with new application domains such as intelligent robot control and real‐time natural language processing. Besides widening the scope of Icon's intended application domain, these experimental concurrent processing notations also encourage programmers to revise existing programs to take advantage of the new language capabilities. For example, concurrent evaluation of the alternative arms of compound goal‐directed expressions is now possible. This paper describes these concurrent processing notations and presents several examples of their expressive power.

Abstract Modern high‐level languages frequently need to collect garbage not only from regions of linked structures similar to LISP's dotted pairs, but also from string regions where data is organized as an array of characters. Some characteristics of string regions that make garbage collection particularly difficult are as follows: multiple pointers to the same characters within the array are allowed and encouraged; all possible character values are legitimate as data, so it is not possible to ‘mark’ a string by overwriting with a reserved character; and a character is generally much smaller than a pointer, so it is not possible to overwrite a single character value with a forwarding pointer to a new location for a particular string. This paper describes the addition of certain information to a string descriptor and enhancements to existing copying garbage collection algorithms that permit linked data structures and strings to be allocated and garbage collected from a shared region of memory in real time. This algorithm is real‐time in the sense that the time required for allocation of each basic unit of memory is bounded by a constant. An analysis of performance is reported, and comparisons are made with traditional garbage collection.

SR is a language for programming distributed systems ranging from operating systems to application programs. On the basis of our experience with the initial version, the language has evolved considerably. In this paper we describe the current version of SR and give an overview of its implementation. The main language constructs are still resources and operations. Resources encapsulate processes and variables that they share; operations provide the primary mechanism for process interaction. One way in which SR has changed is that both resources and processes are now created dynamically. Another change is that inheritance is supported. A third change is that the mechanisms for operation invocation—call and send—and operation implementation—proc and in—have been extended and integrated. Consequently, all of local and remote procedure call, rendezvous, dynamic process creation, asynchronous message passing, multicast, and semaphores are supported. We have found this flexibility to be very useful for distributed programming. Moreover, by basing SR on a small number of well-integrated concepts, the language has proved easy to learn and use, and it has a reasonably efficient implementation.