This website is an archived copy of "Chris's Acorns", now hosted by The Centre for Computing History as part of The Chris Whytehead collection.
To view the page in it's original forms without this header, append "?cfch-archive=orig" to the URL.

Econet

[Networking]

Econet

Introduction

Acorn's 1980 specification for Econet was:

The Econet network is totally democratic in that all stations have equal status and, unless specifically prohibited, any station may communicate with any other with recourse to an intermediary. The only unique station is the one that generates the network clock, but this may be an Atom or a larger system. On larger networks, the stations at the extreme ends are terminated, the termination circuitry is on the Econet board.

Here is a 1982 Econet network:

 Econet Network 1980

A shared disk facility is provided by a station dedicated to running a program known as the 'file server' which organises disc files for the network. The file station may be an Acorn system 3, 4 or 5 or an Atom with a disc. In the simplest possible configuration the printer station can be a printer connected to an Atom running the 'print server' program. In larger configurations the printer server will include a disc unit to spool files before printing.

Here is a 1984 Econet network:

Econet network diaram 2

The Econet architecture evolved and in 1981, Econet had seperated the terminators and clock from the Interface cards and made them dedicated devices. Meanwhile the stations had become BBC micros with Econet interfaces, although the File server was still a System 3,4 or 5.

Here is a 1988 Econet network:

Simple Econet 1988

A simple, "single-room" Econet network from 1988, where station 7 is a Filestore.

A complex Econet network

A complex Econet network from 1988, it links multiple buildings and uses bridges between them.

Documents

Here are some Acorn Econet brochures:

 Here is the 1986 Acorn brochure APP81 Local Area Networking Econet .

Here is the Econet System user guide which documents the 1982 Econet system.

Here is the Econet Installation Guide which documents the 1984 Econet System.

Here is the Econet Installation Guide from 1988. The last 2 network diagrams, above, are in this manual.

Here are some additional Acorn Econet Manuals:

Econet Infrastructure

The Econet infrastructure is made up of:

Acorn produced starter packs which contained all you needed to set up a small network. It the late 1980's it was the AEH19 Econet Starter Kit and in the early 1990's it was replaced with the AEH51 Econet Starter Pack . I have an example from the early 1990s, when the supply of Econet components has been outsourced to SJ Research.

Acorn produced Econet Test Boxes  to test Econet interfaces.

Bridges

I know of 2 different Econet Bridges:

Clock boxes

I know of 4 different Econet Clock Boxes, 3 from Acorn and 1 from SJ Research. A number of Acorn Econet products can also include Econet Clocks e.g. System 3, 4, or 5 Econet interfaces, Atom Econet Interface, Econet bridge, Econet Filestore E01 & E01S. Also the SJ Research MDFS and BEN contain clocks. See the individual products for details.

Terminators

Socket boxes

Socket boxes connect a station to the network via a flylead. There are both Acorn and SJ Research socket boxes.

Cables & T-Pieces

Stations

Stations are computers with Econet interfaces connected to the network. With the BBC Master, Acorn designed an Econet module which was easy to install because it plugged into sockets on the motherboard. Acorn kept this design for all their subsequent computers up to the RiscPC, except for the A4 laptop. The RiscPC (and A7000) Econet interface plugged into the RiscPC network slot. Probably the only common Acorn computers which do not have an Econet interface are the Electron and the A3010, which were designed for home use.

All Acorn Econet interfaces use the Motorola MC68B54 advanced data link controller which controls the data transmissions.

Third Party Interfaces
In addition to the Acorn Econet modules, at least 3 other companies produced Econet modules for Acorn computers:

Econet servers

There are 2 types of Econet servers, file servers and print servers. File servers serve files to the stations on a Econet network and, except in very early Econets, a file server has one or more hard discs. An Econet network can have one or more file servers.
 
Print servers support shared printers, normally a print server is a BBC Model B with the AES22 Print Server EPROM and is dedicated to printing but can double as a Econet station.

Gateways

A Gateway connects an Econet network to another network.

Transient suppressors

Transient suppressors block transient signals caused by external electrical events and protect the network. They are typically used where an Econet spans two different buildings to protect the network from external events (e.g. lightning strikes).

Test Equipment

Acorn also produced test equipment to help diagnose Econet faults.

Econet Software

While most Econet software was provided in ROM (on the client) or on the server by Acorn (or SJResearch), there were a number of thrird party Econet products. These include:

Angelsoft AppFS

AppFS is a software Application Accelerator which speeds the loading of software by client stations.
 
Here is Angelsoft AppFS Release 3 .

Digital Services Ltd NetGain

NetGain is a 'High Speed Application Loader'. NetGain was available for Econet or Ethernet and consisted of a Licence Card podule, end user licence packs and the software on a 3.5" disc. In use it marked reduced loading times. There is a review in Archive Vol.7 Isuue 1 (October 1993) page 77.
 
Here is the Digital Services NetGain Licence Card  and more details of NetGain.