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The CommunITel Viewdata System was introduced as a package in 1985 by CommunITel Limited although development of the package had begun in 1983. The market was mostly educational and between 3000 - 5000 copies were sold.

There were two main versions of the package,

  1. a Level 1 - Local system designed to work on a stand alone BBC microcomputer system with DFS or ADFS fitted or on a networked BBC microcomputer fitted with an Econet interface.
     
  2. a Level 2 - Host system designed to work as both a local system and as a host system providing access to viewdata pages over the telephone lines using the CommunITel MODEM (other MODEMs could also be used).

Both packages were substantial and came with detailed documentation which would allow the more technical users to customise the system for their own use.

Many viewdatabases were produced in schools using this system, covering topics as diverse as Computer Science, Modern Foreign Languages, English, Health Care and Administration. Sadly almost all these databases have not survived.

The growth of the internet in the 1990s and the development of ever faster data links sounded the death-knell for viewdata-like systems and saw the demise of systems like PRESTEL and Teletext.

At the start of 2020 the Archive was fortunate to be gifted a large collection of development material for the CommunITel Viewdata System by its chief developer, Bill Olivier. Included in this collection were;

  • hundreds of floppy disks of different versions,
  • floppy disks of the source code for the various component programs used by the system,
  • annotated listings,
  • provisional documentation,
  • copies of the software used to compress the BASIC program listings for the released versions so that they would work on BBC microcomputers with DFS and NFS fitted,
  • technical documentation, including the file structure of the DFS random access database yclept "VWDB".

Please use the links below to access the archive of CommunITel material.

 

DOCUMENTATION

 

 
This is the Level 1 Reference Manual covering the stand alone and local host system.
This is the Level 1 Tutorial Guide covering the stand alone and local host system.
Bill Olivier's Business card as Technical Director
An internal document outlining the structure and function of the CommunITel Vewdata System
The CommunITel Viewdata System uses a proprietary direct access filing system to store pages on a floppy disk. BBC micro floppy discs are limited to 31 entries. The direct access filing system allows up to 195 pages on a single 80 track floppy disk, although the theoretical limit is 255.

This document has been retyped by the Archive from the original, faded computer printout.

Viewdata frames are stored in a single file, VWDB. A machine code hashing algorithm is used to place the files into the database for speed of access.

The notes for the ADFS version of the Viewdata System. These are the prototype notes produced before including in the Level 2 manual.

The print quality of the original was poor.

 

   
   
   
SOFTWARE

 

 
Source Files This is the set of CommunITel Viewdata System source files dated September 1985. There are seven discs in the set, numbered 0 to 6.

Disc 0, Disc 1, Disc 2, Disc 3, Disc 4, Disc 5, Disc 6

   
Prototype Random
Access Procedures
The DFS version of the Viewdata System uses a single large file, VWDB, to create a random access filing system to get around the 31 file limit in the disc catalogue. In this way up to 195 viewdata frames can be stored in the single file.

A hashing algorithm is used to allow direct access to each frame using its frame ID as the key.

Prototype source files, Annotated listing

   
   
   
   
   
   
   
   
   
   
   
 

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