Free configuring virtual memory software for linux

The Linux Virtual Server is a highly scalable and highly available server built on a cluster of real servers, with the load balancer running on the Linux operating system.

The architecture of the server cluster is fully transparent to end users, and the users interact as if it were a single high-performance virtual server.

The basic goal of the Linux Virtual Server Project is to:
- Build a high-performance and highly available server for Linux using clustering technology, which provides good scalability, reliability and serviceability.

High Level Virtual Machine is a toolkit for developing virtual machines for dynamic languages.
The High Level Virtual Machine is:
- Based on LLVM (Low Level Virtual Machine). LLVM is HLVMs sister project. HLVM gains tremendous capability from LLVM in the areas of code generation, bytecode storage, runtime execution, etc.
- Aimed at supporting dynamic languages such as Ruby, Python, Perl, Jython, Haskell, Prolog, etc.
- A complete compiler developers toolkit for creating new languages easily. To write a new compiler, language designers simply write a plugin that describes the language to HLVM and how to translate the grammar productions into HLVMs comprehensive Abstract Syntax Tree (AST). After that, HLVM handles all aspects of code generation, bytecode storage, XML translation, JIT execution or interpretation, and native compilation.
- A language interoperability framework. Because all front end compilers generate code in the same AST, they can interoperate. Use of the runtime library for common constructs (e.g. "string") allow even complex data types to be shared between languages. Users of HLVM can write complex programs in multiple languages and be assured the result can be executed efficiently.
- A code management system including code revisioning, interface versioning, automated recompilation, separation of workspaces, etc.
- Currently under development. Project started April 20th, 2006. Stay tuned to this web site for future developments.

RPM Delta Compression Virtual Update Repository is an experiment to explore the possibility of significantly reducing the bandwidth required to apply updates to a Fedora installation.
This software includes a server which provides a virtual update repository to clients such as yum, up2date, or other update tools. RPM Delta Compression Virtual Update Repository also includes a utility to create and maintain a RPM delta repository.
The server will attempt to generate the update RPM from a small delta file applied to a locally stored RPM from the original distribution.
Enhancements:
- This version utilizes the SuSE deltarpm tool as the underlying delta generator.
- It features both HTTP virtual update of the RPM repository (using Tomcat servlet container) and command line tools for generating update RPMs from a delta repository.

Joeq is a virtual machine and compiler infrastructure designed to facilitate research in virtual machine technologies such as Just-In-Time and Ahead-Of-Time compilation, advanced garbage collection techniques, distributed computation, sophisticated scheduling algorithms, and advanced run time techniques.
Joeq is entirely implemented in Java, leading to reliability, portability, maintainability, and efficiency. It is also language-independent, so code from any supported language can be seamlessly compiled, linked, and executed -- all dynamically.
Each component of the virtual machine is written to be independent with a general but well-defined interface, making it easy to experiment with new ideas.
Joeq is released as open source software, and is being used as a framework by researchers on five continents on topics ranging from automatic distributed virtual machines to whole-program pointer analysis.
Joeq is a virtual machine and compiler infrastructure designed to be a platform for research in compilation and virtual machine technologies. We had three main goals in designing the system. First and foremost, we wanted the system to be flexible. We are interested in a variety of compiler and virtual machine research topics, and we wanted a system that would not be specific to researching a particular area.
For example, we have interest in both static and dynamic compilation techniques, and in both type-safe and unsafe languages. We wanted a system that would be as open and general as possible, without sacrificing usability or performance.
Second, we wanted the system to be easy to experiment with. As its primary focus is research, it should be straightforward to prototype new ideas in the framework. With this in mind, we tried to make the system as modular as possible, so that each component is easily replaceable. Learning from our experience with Jalapeno, another virtual machine written in Java, we decided to implement the entire system in Java.
This makes it easy to quickly implement and prototype new ideas, and features like garbage collection and exception tracebacks ease debugging and improve productivity. Java, being a dynamic language, is also a good consumer for many of our dynamic compilation techniques; the fact that our dynamic compiler can compile the code of the virtual machine itself means that it can dynamically optimize the virtual machine code with respect to the application that is running on it. Javas object-oriented nature also facilitates modularity of the design and implementation.
Third, we wanted the system to be useful to a wide audience. The fact that the system is written in Java means that much of the system can be used on any platform that has an implementation of a Java virtual machine. The fact that Joeq supports popular input languages like Java, C, C++, Fortran, and even x86 binary code increases the scope of input programs. We released the system on the SourceForge web site as open source under the Library GNU Public License.
It has been picked up by researchers on five continents for various purposes, among them: automatic extraction of component interfaces, static whole-program pointer analysis, context-sensitive call graph construction, automatic distributed computation, versioned type systems for operating systems, sophisticated profiling of applications, advanced dynamic compilation techniques, system checkpointing, anomaly detection, secure execution platforms and autonomous systems. In addition, Joeq is now used as the basis of the Advanced Compilation Techniques class taught at Stanford University.
Joeq supports two modes of operation: native execution and hosted execution. In native execution, the Joeq code runs directly on the hardware. It uses its own run-time routines, thread package, garbage collector, etc. In hosted execution, the Joeq code runs on top of another virtual machine. Operations to access objects are translated into calls into the reflection library of the host virtual machine.
The user code that executes is identical, and only a small amount of functionality involving unsafe operations is not available when running in hosted execution mode. Hosted execution is useful for debugging purposes and when the underlying machine architecture is not yet directly supported by Joeq. We also use hosted execution mode to bootstrap the system and perform checkpointing, a technique for optimizing application startup times.
Joeq system consists of seven major parts:
- Front-end: Handles the loading and parsing of input files, such as Java class files, SUIF files, and binary object files.
- Compiler: A framework for performing analyses and optimizations on code. This includes the intermediate representation (IR) of our compiler.
- Back-end: Converts the compilers intermediate representation into native, executable code. This code can be output to an object file or written into memory to be executed. In addition, it generates metadata about the generated code, such as garbage collection maps and exception handling information.
- Interpreter: Directly interprets the various forms of compiler intermediate representations.
- Memory Manager: Organizes and manages memory. Joeq supports both explicitly-managed and garbage-collected memory.
- Dynamic: Provides profile data to the code analysis and optimization component, makes compilation policy decisions, and drives the dynamic compiler.
- Run-time Support: Provides runtime support for introspection, thread scheduling, synchronization, exception handling, interfacing to external code, and language-specific features such as dynamic type checking.

C# Java Virtual Machine is a tiny implementation of the Java VM, including simple native classes. This project is written using the C# language. The VM is very easily expandable by writing additional native or Java classes.
Enhancements:
- The DbConnection class, which provides a connection to MS SQL or PostgreSQL using ADO.NET, was added.
- The Syst.MachineName method, which returns the machine name, was added.
- String.startsWith and String.endsWith functions were added.
- Some comments for VM.cs were written.

Virtual Collaboratory is a directed discussion forum based on Mailman and Smartarchiver that provides for threaded short and long term discussions.
Virtual Collaboratory includes a calendaring function, integratation with the Elluminate meeting software, document exchange, version control, a research resource center, custom categorizations, FAQs, and the ability to search for users with similar interests.
Enhancements:
- Refactored Plone into three separate products
- Better Elluminate integration
- I18N support via Py-MYCMSs traslate functionality
- Refactored smartarchiver as a py-mycms system
- Easier isntallation through Install Constancts
- Front page Alerts
- BlogPoster blog management system (works with your blog to help groups collaborate on blog content)
- No longer requires specially patched versions of Zope & plone. (Authentications now done through the PyMyCMSUserFolder)
- Virus checking (pyclamav) now supported if pyclamav is installed

Virtual Tomcat project is a set of scripts designed to ease administration tasks involved with hosting multiple JVM instances and domains using Apache Tomcat and HTTPd.

The system (which uses jsvc to spawn instances) allows users to deploy their own applets from within their home directories, as well as allowing full access to /manager and /admin applets.

lx_lib handles memory allocations as structures, keeping important information such as the remaining allocated space and the length of the used string internal to each variable (or descriptor).
Much of it was initially inspired by Dan Bernsteins stralloc library, but the two are not compatible, nor has there ever been any intention to make them compatible.
Main features:
- strings need not be scanned to determine their length
- the amount of allocated string remaining is easily determined
- promotes more secure programming practices
- if used correctly, lx_lib can offer a significant speed increase over traditional methods
- easy-to-use methods for manipulating strings
- generic descriptor support for buffered i/o
- generic descriptors enable fast scanning of input for specific characters (e.g. a newline)
Enhancements:
- Bits of the lx_map() interface have been updated for use with the 20060228-1 release of libnaw.