Acorn User 4/AUCD4.iso/acorn/documents/appnotes/216-230/228c.arc/Text

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2nd August 1993
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Support Group Application Note
Number: 228
Issue:  Purchase and installation of a simple AUN Network.
Author: Carl Sellers
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Applicable Hardware:

Related Application Notes:


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Copyright (C) Acorn Computers Limited 1992

Every effort has been made to ensure that the information in this leaflet is
true and correct at the time of printing. However, the products described in
this leaflet are subject to continuous development and improvements and
Acorn Computers Limited reserves the right to change its specifications at
any time. Acorn Computers Limited cannot accept liability for any loss or
damage arising from the use of any information or particulars in this
leaflet. ACORN, ECONET and ARCHIMEDES are trademarks of Acorn Computers
Limited.
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Support Group
Acorn Computers Limited
Acorn House
Vision Park
Histon
Cambridge
CB4 4AE
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Purchase and Installation of a simple AUN Network


This document will provide the reader with sufficient information to allow
them to construct a simple Ethernet based network using RISC OS machines and
the AUN/Level 4 Fileserver software.

It is, however, beyond the scope of this document to cover all aspects of
Ethernet design and installation. Those readers who seek information on more
complex network topologies should refer, in the first instance, to the
documentation supplied with the AUN/Level 4 Fileserver.

Applicable Hardware:  All Archimedes machines.  All Ethernet cards fited
with an AUN Boot ROM.

Related Application Notes:  Optimising AUN Network performance.


1   Introduction
This note is intended to give guidance to anyone wishing to purchase and
install an AUN Network. It is designed for those that have not attempted
such an exercise before, and concentrates on straight forward, simple
networks. It does not attempt to cover issues such as connection with other
network types, for example Econet, Nexus or non-Acorn systems. Likewise it
is beyond the scope of this document to discuss issues surrounding the use
of more complex topologies involving Gateways, Bridges or Repeaters. To
address these the reader should contact a suitably qualified professional
network installer and/or read the manuals supplied with the AUN/Level 4
Fileserver.


2   First steps
A network is a means of connecting two or more computers together in order
to allow them to share resources and communicate.  The current Acorn
networking model is called Client-Server. Clients are  machines that require
services such as file and application access or print services. These
machines are generally distinct from those that provide these services
(servers).

A small network may consist of one machine that acts as a file server and
print spooler that is dedicated to this purpose and a number of machines
that can utilise the services that it provides. There are restrictions of
course regarding numbers of clients that can be sensibly accommodated by a
server, and these are discussed in the following pages.

Installing a network first involves ensuring that:

    • the correct hardware is available in all participating machines

    • the physical network is correct and working

    • all machines are correctly configured

    • the server software is installed

All these steps will be covered in some detail.  Some background information
on Ethernet, which is the technology described in this note, is given in
Appendix A. This document deals with Thin Ethernet, as this is the type that
is supported by all types of Ethernet card for RISC OS machines. Here are
some statistics:

    Maximum length of one cable segment:    185 metres

    Maximum number of stations on a segment:    30

It is important to note that the 185 metres includes all the cabling -
including drop cables, if used.

There are two main ways to install the cabling for a network. The simple way
is to run the cable as a "daisy chain" from machine to machine, using
"T-pieces" to connect the cable to a network card, as shown in the  diagram
overleaf.

(See Diagram No.1)

Illustration of a typical Thin Ethernet (10Base2) network and its component parts.

There is nothing wrong with this sort of network. It is ideal for
non-permanent installations, and the connectors that attach the bits of
cable together (BNC Connectors) are well engineered and do not come apart
accidentally. But it is possible that they can be detached, breaking the
continuous cable run and therefore bringing the whole network down.

For more permanent installations, a socket-box approach is preferred. Here
again, there are two main choices. They can either be simple, just
consisting of two BNC connectors that run down to the machine and back, but
which require a "short linking cable" between the BNC outlets on each unused
box, and the more expensive "make before break" box which allows the station
to be disconnected without bringing the network down. These two types are
also illustrated below:

(See Diagram No.2)

3   Obtaining the components
To use Ethernet you need RISC OS 3.1 or later in every machine. Each machine
must have an Ethernet card fitted. These are available from a variety of
sources, but different cards are required for different machines. Prices may
vary from third party suppliers, and it is possible that quite considerable
discount may be given for quantity. At the time of going to press the
following information is believed to be correct:

Platform                   Supplier (Sales Code)

A5000, A400 Series         Acorn   (AEH54)
                           Atomwide
                           Risc Developments (4600e)
                           Oak Solutions


A3000 (A3020 A4000)        Atomwide
                           Risc Developments (4601e)
                           Oak Solutions

A3020, A4000               ICubed (Isolan)
                           (Network slot)
                           Risc Developments


Check with the supplier that the Ethernet card contains the AUN client
software. (Some cards are available with different software loaded).

Cables, T-Pieces and Terminators can be obtained from a variety of sources.
One well known supplier is Pronet   - a list of sutiable components is shown
below:

2 Metre drop cable (BMM58/2)
Twin 2 metre cable (BGM/2) (Includes T-Piece)
T-Piece  (35031)
Terminator  (35098/50R)

There are a number of companies that specialise in Ethernet boxes, trunking,
make-before-break connectors etc, but these lie outside the scope of this
document. Refer to your local dealer for information.


4    Fitting the network cards
When your cards have been purchased, plug them into the machines as per the
manufacturers' instructions.

(See Diagram No.3)

Connect the machines via the BNC connector on the Ethernet card to the
network. Ensure that the network has a terminator at each end of the cable
(as shown in the earlier diagram), and that it forms a continuous run of
wire with the Ethernet card BNCs tapping off the cable.

5    Configuring machines
With the machines powered up, it is necessary to configure the machines to
set their station number and load the Ethernet software from the memory on
the Ethernet card. If the machines have no hard disc of their own, you may
wish to boot them from the fileserver at power up. This is covered later in
"Hints and tips".

To ensure that the correct Ethernet software is loaded, ensure that the
machine is switched on and is displaying the normal desktop. Press F12. At
the * prompt type the following command:

               *Configure BootNet on

When you have done this press Return. Now reboot the machine by pressing the
button marked Reset whilst holding down the key marked Ctrl.

Take a floppy disc with the SetStation utility on it (for example the Level4
Fileserver application disc).  Insert the disc into the machine that is
going to act as the fileserver (ie one that has a hard disc)  and then:

          • Click-select on the floppy disc icon

          • Double click-select on the SetStation program

          • Type 254 at the prompt.

          • Reboot the machine.

This process will set the station number of this station to 254, which is
the customary number for a fileserver. Repeat this exercise at every other
additional machine on the network.  Ensure that you choose a different and
unique number for each one. It is recommended that you start at say 20, and
then go up in units of five or ten.

The machines are now ready to talk over the network.


6    Installing the Fileserver
The Level 4 Fileserver manual contains a great deal of advice on setting up
a fileserver, and there is no substitute for taking the time to read through
it carefully. If you know that your fileserver will be doing a number of the
following :

        • have to handle hundreds of users

        • be accessed by more than six machines at any one time for
          intensive tasks

        • be used for application serving

        • does not have a normal ADFS hard drive (or a standard IDE drive as
          per the A5000 et al)

then you are strongly advised to read the manuals supplied with the
AUN/Level 4 Fileserver software.  However, if you are setting up a
fileserver which will only be accessed by a small number of users for saving
their own data then you may take some short cuts.

Make sure that the root directory ($) of the hard disc is not littered with
applications and resources. Ensure that files are grouped in a reasonably
tidy and logical manner; this will make it easier for other users to find
things on the fileserver. Create a directory structure on the hard disc
which matches the one in the following illustration.

(See Diagram No.4)

Level 4 directory structure.

As you become more experienced with the management and use of the fileserver
you may wish to change this structure, but for the time being it is
important that you copy this structure exactly. You can find copies of these
applications on either the Level 4 Fileserver disc or the applications discs
supplied with the machine.

Create a directory called Syst and copy !Scrap into it, this will be needed
when you logon as a system privileged user to perform day to day management
tasks.

Name the hard disc with a name that you want it to be seen as over the
network. Something inspired like Level4 will do, but not %^&76! Disc names
of 10 characters or more in length are best avoided at this stage, as their
use requires changes to be made to the exports file in Level 4.

Double click on the !Server icon, when the pyramid icon is displayed on the
icon bar your server is running. You should be able to move to another
station and click-menu over the Net icon on the Icon bar, move to the Logon
box and logon to the fileserver. Type the name of the fileserver disc on the
top line, Syst as the user name - no password is required, just hit Return.

(See Diagram No.5)

Performing a Logon from a client station to the fileserver.

A filer window will open, showing the contents of the directory $.Syst. To
access the whole of the disc, move the pointer over the Net icon on the icon
bar click once on the menu button and click-select on Open '$'.   A filer
window will open, showing the root directory of the fileserver, and you can
share this data as if it were your local hard disc. Refer to the Level 4
Fileserver Managers Guide in conjunction with Section 8 of this document if
you wish to restrict user access to the fileserver disc and Section 9 if you
wish to set up !ArmBoot files for users.

7    Installing the Spooler
You may wish to share a printer between the machines on the network. This
can be done with the !Spooler application.  Firstly, attach the printer to
the machine - it can be any machine on the network but you are strongly
advised to ensure that this machine has its own local hard disc which
contains the copy of !Spooler. Where the number of hard discs on the network
is limited it might be sensible to connect it to the machine that is acting
as a fileserver, and reserve this machine as a dedicated resource.

Double click on the !Spooler application, and then click-select on the
Spooler icon on the Icon bar. This will open up a window with two printers
displayed; Matrix and Laser. In this default configuration, Matrix is
configured to print to the Parallel port, and Laser is configured to print
to the Serial port. You may copy or delete these printers, or alter the
connections by menuing on the printer icon and setting them up as required.

On a client machine, load a copy of !Printers (either from local disc or
from the network fileserver).  This note assumes familiarity with this
application, and that you can set it up with the correct printer definition
file. If you are unsure how to do this then please refer to the section on
Printing in the RISC OS User Guide.  The setup sequence is shown in the
illustration below. Click-menu on the Printers icon and click-select on the
Printer Control... box.  Click-menu again on the appropriate printer and
select Connections... In the Connection box click on the Econet button (yes,
Econet!), and select the printer name from the associated menu window.  Save
the options, and you are now ready to print.

(See Diagram No.6)

Illustration showing how to configure !Printers for Network use.

8    Using the system - Users & !Manager
As described, you can log onto the fileserver as user "Syst". This user has
special privileges, one of which is "ownership" of all the fileserver disc,
and can therefore be rather dangerous. It is wise to add a password to the
system user. This password must be kept a closely guarded secret. It is also
desirable to create other "users" of the system who can have access to just
those areas of the fileserver that they need. For these operations, you need
to use !Manager.

You may use !Manager on the station that is acting as the server, but not
whilst the server is running. It is strongly recommended that you use it on
one of the client machines connected to the network.

Load !Manager, and click-select on its icon on the Icon bar. After a pause,
a window will open with a display of all the Acorn fileservers available on
the network. In this single-server network there will be either one or two
servers - shown by the disc name, or "local server" if you are running
manager from the server machine. Selecting this fileserver will open a
window with all the users in it: Syst, Guest and Boot.

Click-select on Syst, which opens the "profile" for this user. Enter a
suitably secure password (minimum 6 characters, max 21), and click-select on
Update as shown below.

(See Diagram No.7)

Setting the password for the user "Syst".

You may wish to create new users, which can be done intuitively via the
Users window, but do refer to the Level 4 manual for a full description. If
you produce a user called, for example "Class1" or "JSmith" and then click
on Create User Directory, then click on Update, it will produce what is
called a "User Root Directory" or "URD" for that user. This means that if
that user logs onto the fileserver as "Class1" then the directory viewer
seen is the Class1 directory (which will be empty, of course) This is the
starting point for this user on the fileserver, where private data and
applications can be safely kept.

If you have decided to enable the Space Accounting feature of the fileserver
(available from the icon bar set-up menu) then you may use !Manager to
assign appropriate space to each user, simply by dragging the Space slider
on the user profile window. Space accounting is set on by default.

9    Tuning the system - !ArmBoot files et al It is often a very good idea
to ensure that machines, when they are switched on, log onto the fileserver
automatically and load the required system resources. These resources
include !System, which hold copies of additional modules which may be
required by applications, !Fonts which holds fonts that are not in the RISC
OS ROMs and !NetUtils, which ensures correct network operation. To do this,
it is necessary to create a small !ArmBoot file, which is an obey file that
is run by a machine when it logs onto the fileserver.

Start !Edit on the Server machine and create an Obey file. Into this obey file type:

       *Rmreinit BroadcastLoader
       *Unplug BroadcastLoader
       *Desktop -f Deskstart

and save this file as name !Armboot in the root of the fileserver disc,
ensuring that its access has been set to Public Read (WR/r). It is important
to disable Broadcast Loader,  as it adversely affects the performance of
Ethernet networks!

Next create a Text file and type into it:

         *Filer_Boot Net:$.!System
         *Filer_Boot Net:$.!Fonts
         *Filer_Boot Net:$.!NetUtils

and save it under the filename Deskstart in the root of the fileserver.
Ensure that it also has its access rights set to Public Read. (Note. In the
example shown above full pathnames; Net::Level4.$.!System, could have been
used for each file in place of Net:$.)

Now using !Manager, open up the profile for the user Boot, and make sure it
has the boot option set to Run.  Next visit each client station that you
wish to boot automatically and press F12. At the * prompt type:

       *Configure boot
       *Configure filesystem net
       *Configure FS 128.254

and then reboot the machine. It will then log onto the fileserver as user
Boot, run !System, !Fonts and !NetUtils.  This will save a lot of time on a
busy network as it will ensure that the machine performs the minimum of
operations when the user logs on by his or her user name.

For printing, or moving data between applications, the RISC OS machine needs
to have access to an application called !Scrap. This application holds
temporary data during these operations. It is advised that a copy of !Scrap
is copied off the Level 4 applications disc into the User Root Directory of
each user, so that they each  have access to this resource.

The appropriate use of !ArmBoot files can greatly enhance the service
provided to the users of the network. It is possible, with boot files, to
arrange for the root directory ($) to be automatically opened and for
certain applications to be already loaded when a client logs onto the
fileserver. This involves the use of another !Armboot file, that this time
exists in the Users Root Directory (URD). An example might be:

            *Filer_OpenDir Net::Level4.$.Apps
            *Run Net::Level4.$.Apps.DTP.!EasiWrite

Again, save this Obey file in the User Root Directory, and ensure that the
user has the boot option set to Run.

10   Hints and tips
You may run the Server in the desktop, but you can also run it in standalone
mode. Running the fileserver in this way usually results in a 25%
improvement in file loading time. However, in this mode you cannot utilise
any other application, for example !Spooler, on the same machine.

In the desktop, in order to ensure the best possible performance, it is
advisable to select the lowest possible resolution screen mode available -
12, 11 or even 0.  Do not have the Status window open unless you really want
to monitor requests to the fileserver.

A sensible number of client machines to support at any one time might be 15,
as this number is known to provide acceptable performance in the vast
majority of circumstances. As circumstances change this figure may need to
be revised. It is worth noting that some applications naturally load more
slowly than others on a network, due to the number of files that are
accessed during the course of loading them.  As a rough guide, Impression
should load to 10 stations in around 2 minutes, and many popular
applications are signficantly faster than this.

You may wish to start the server automatically on power up. To do this, it
is suggested that you use the !Boot file that comes with the product, but if
you are adventurous, it is not difficult to write your own, or to utilise
the desktop boot facilities provided by RISC OS 3.

Appendix A:  Ethernet types

Ethernet is a world-wide industry standard which is supported by most
computer manufacturers.  Because it is an industry standard, it means that
equipment from a variety of different manufacturers can coexist on the same
network, even if the software cannot understand the messages produced by
other machines! Ethernet comes in three flavours: "Standard Ethernet" or
10Base5; "Thin Ethernet" (sometimes known as Cheapernet) or 10Base2; and
"TwistedPair Ethernet" or 10BaseT.

Standard Ethernet is very expensive, requiring thick Coax Cable and
expensive connection outlets to each machine. It is often used for backbone
networks.

Twisted Pair Ethernet is used predominently in offices. In this system, each
machine has its own private wire to a "hub", where signals are amplified and
broadcast to all other machines.

Thin Ethernet is the most popular form of Ethernet, and is especially
suitable for schools. It is a "Bussed" network using cheap coax cable, and
cheap connections to each machine.

A Bussed network means that the network consists of a long cable that starts
at one terminator, snakes its way past every machine on the network, and
ends at another terminator.  All flavours of Ethernet run at the same speed;
10 Million bits per second (10Mbps). The difference between standard
ethernet and thin ethernet is the maximum permitted length of a single piece
of cable, and the maximum number of stations that can be connected to one
piece of cable, or "segment".

Appendix B: Addresses

Atomwide
23 The Greenway
Orpington
Kent
BR5 2AY

Tel. [phone]
Fax [phone]

Pronet Dataparts
Unit 6
The Galloway Centre
Hambridge Lane
Newbury
Berkshire
RG14 5TL

Tel  [phone]
Fax [phone]

Oak Solutions
Suite 25 Robin Enterprise Centre
Leeds Road
Idle
West Riding
West Yorks.
BD10 9TE

Tel [phone]
Fax [phone]

I3 (ICubed)
The Paddocks
Cherry Hinton Road
Cambridge

Tel [phone]

RISC Developments
117 Hatfield Road
St Albans
Hertfordshire
AL1 4JS

Tel [phone]