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THINK  Cyclades

Technical History of CYCLADES -
A Technical Tour

General Information:


"Nodes" (Routers) are MITRA-15 minicomputers with 16K words. Communication lines are point-to-point PTT leased lines, ranging from 4.8 Kbs to 48 Kbs. Telephone lines and V24 interfaces, typically using 19.2 Kbs. base-band modulation on voice grade circuits connect all host computers. 

[Pouzin 1974]



Specific components within Cigale provide basic services such as echoing, statistics recording, debugging aids, node configuration, artificial traffic and a clock. Other services  are available with regard to a particular packet such as priority, tracing, and routing.

User aids are available to help  retrieve information regarding their own traffic, for example, diagnostics and delays. A particular service is ECHO, which returns packets to their source. In order to provide for traffic measurement, a set of tools gathers statistics on real traffic, generating artificial traffic, and measuring specific parameters. 

Here is a list of applications that were in development in March 1975:

  • Processors available under time-sharing or remote batch include: APL, SOCRATE (a general data base manager), MISTRAL (documentation and information retrieval).

  • Application that allowed access to a chemical data bank (THERMODATA), a circuit simulator, a computer simulator, an economic modelling system.

  • Specific application for social sciences, linguistics, faculty management, CAI, a hemophiliac data bank.

  • Plans for pilot applications in the Customs Department and military laboratories.

[Pouzin 1975]


Basic Implementation Issues

Cigale was developed as a communications tool of a computer network. Its design allows it  to become a component of larger systems and carry any data traffic in a transparent mode. Except for timing parameters, Cigale does not impose any particular protocol. It may include custom-tailored components to implement specific services.

Error and flow control are optional services- they can be either on or off. Therefore, the only services available are basic services that implement fragmentation-reassembly by the transport station. Error control on letters is an additional service; this service can be  either on or off. Error control must be on in order to use flow control, thus if flow control is on, so is error control. The reverse is not true (error control on while flow control is off).

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Written by the THINK Protocols team, CS Dept, UT Austin
Please direct comments to Chris Edmondson-Yurkanan.

This document was last modified on Tuesday, 11-Jun-2002 10:18:00 CDT.