The Database OS (DBOS) is a Java prototype of a high level computing environment. It currently has its own language, compiler (to JVM), and visual debugger It features relational semantics, query ability, a class hierarchy, a source code reflection system, automatic persistence, garbage collection, and an object browser interface.
The Memory Pool System is a very general, adaptable, flexible, reliable, and efficient memory management system. It permits the flexible combination of memory management techniques, supporting manual and automatic memory management, in-line allocation, finalization, weakness, and multiple concurrent co-operating incremental generational garbage collections. It also includes a library of memory pool classes implementing specialized memory management policies.
HotCache is a transactional distributed caching system that runs on top of most RDBMSes. It provides an object-relational mapping tool that makes the use of embedded SQL unnecessary and saves tedious mapping programming. It enhances RDBMS commit functionality by adding commit-broadcast transactions where data is committed to the database and at the same time pushed to all other client caches, in essence keeping the data at remote clients hot. This improves performance by orders of magnitude (as most data access can be done locally) and reduces the load on the database server. The commit-broadcast transactions are implemented using UDP multicast for maximum network utilization. HotCache provides a sophisticated event framework that allows the client to register interest in business objects and be notified when changes are committed. The event framework is built so that it can be easily integrated with other systems' event-loops, eliminating multi-threading problems, etc. Notification can also be configured to take place in an asynchronous/multi-threaded method.
RC is a dialect of C that adds safe, region-based memory management to C. Region-based memory management allocates objects in a program-specified region. Objects cannot be freed individually; instead regions are deleted with all their contained objects. RC is safe, since for each region, r, it maintains a reference count of the number of external pointers to objects in r (i.e. of pointers not stored within r). Deleting a region with a non-zero reference count causes a runtime error (abort). RC's compiler, rcc, is based on gcc.
RScheme is an object-oriented, extended Scheme implementation with a compiler that targets C or (RScheme's own) bytecodes. It has features expected from a modern language: an object system, reflection, modules, namespaces, safe macros, threads, a system call interface (including sockets), separate compilation, and persistence, as well as the formal basis and power of the Scheme programming language. RScheme also features a powerful, elegant foreign code interface.
YAPP XSLT is a recursive descent parser and lexical scanner generator (aka compiler compiler), implemented entierly in XSLT. The generated compiler stylesheets allow users to parse and process text content. The package also includes a BNF parser parser and left-recursion eliminator, and an example XPath grammar.
Jacob is a stand-alone Oberon-2 compiler. It compiles a single Oberon-2 module together with its imported modules and links everything together to form an executable. It implements the full Oberon-2 language specifications. External modules allow developers to write library modules in other languages. Instead of an explicit dispose function a garbage collector is implemented using the mark-and-sweep algorithm. There are command line options for enabling and disabling NIL, index, range, and assertion checks.