Welcome to Ram Meenakshisundaram's Transputer Home Page

"…sequential computers are approaching a fundamental physical

limit on their potential power. Such a limit is the speed of light…"


     Helios for Transputer

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General Information

Helios is a micro kernel operating system for embedded and multiprocessor systems. The operating system is modular in design and can scale from an embedded runtime executive up to a fully distributed operating system. It has adopted many internationally recognised standards: POSIX, BSD, X, TCP/IP and Windows. Existing programs can thus be ported to Helios and remain easy to maintain.

A UNIX like csh supports a variety of development and monitoring tools for the target hardware. A host support server (IOServer) provides disk, keyboard, networking, screen and peripheral services to target application programs. This allows services normally found only on the host development computer to be fully accessible by target programs as if they were local services. The services conform to the Helios server specification, which means the services can be transferred transparently from the host to the target without modification to the target application. For example, networking applications can be developed using host ethernet facilities on standard development boards while target hardware is being designed.

Distributed versions of Helios feature a comprehensive suite of utilities and libraries for parallel/distributed computing. Helios provides several models of parallel computation, each suited to different parallel problems.

The smallest Helios module is the kernel. It supports memory management, multi tasking, synchronisation primitive and interrupt handling. Further modules can be added to the kernel to build a Helios nucleus, these can include code loader, task manager, and message passing. Libraries and device drivers may also be built into the nucleus.

Real-time versions of Helios provide fully deterministic response times for all operations. The kernel implements a multi-level priority based real-time scheduler. The multitasking time slicing quantum is user programmable and can be turned off if desired. Embedded support includes utilities for splitting and building custom nuclei and ROM file servers.

Language and Libraries

Tools and Utilities
Server Support
Kernel Features
Multi-User Version
Multi-Processor Version
Helios PC 

The Helios PC IOServer has two windowing systems: PC text overlaid windows and Microsoft Windows support. The Windows IOServer is compatible with the Helios Windows Graphics Library. The IOServer also includes an int60 trap handler which allows PC TSRs to be called directly from target hardware. Connection of target hardware to Helios can be through RS232, Parallel, PC Bus, Link, or ComPort. Contact Perihelion for a list of supported boards.

Helios SUN

Helios SUN is a port to Sun Micro System workstations. Supported workstations include Sun 3 and 4 machines. Helios SUN includes IOServer internet services which merge the socket domain of the host computer to the Helios target. This means that both host and target programs can easily communicate to each other via sockets. A practical example would be a Helios X client program directly calling the host XServer. Helios SUN includes Ethernet I software, enabling remote access to and from networked resources. A network daemon called hydra allows remote access of target hardware from anywhere in the network. Helios SUN supports both SUN View and Open Window interfaces. Helios SUN includes support for a wide range of SBUS and VME boards. Contact Perihelion for a list of supported boards.

Helios Distribution and Support Software

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