🚀 go-pugleaf

dac@ukc.ac.uk (David Clear) writes:
|> I am having problems getting the Inmos B008 TRAM motherboard to work. On
|> running the iserver program, I receive the message:
|> 	Error - iserver - unable to write byte <n> to the boot link.
|> The manual says that this error message could be caused by the object module
|> being in the incorrect format. This does not help me. 

The message means that the transputer has stopped accepting
and acknowledging the bytes that the server is trying to send it.
There are several reasons why this might happen.

1.  The server is not actually talking to a tranputer.
     There are several possibilities here, including the server having
     the wrong idea of the B008's address in  the PC.  The address
     is set by switches on the board and by an environment variable
     or command line switch in the server, unless you have a DOS
     device driver for the B008 in which case there are configuration
     options in CONFIG.SYS
2.  The boot file you are trying to send is not a transputer boot
     file at all, or is corrupt in some way. This is unlikely to be the case 
     if it just came out of a compiler/configuration tool :-)
3.  The "bootstrap" (the initial few bytes of code at the front of the
     bootfile which is executed first to load in and jump to the rest of 
     the code) has failed to work properly.  For example, some
     bootstraps look for an environment variable (IBOARDSIZE) to find 
     out how big the root transputer's memory is.  If the variable is set 
     to the wrong size the bootstrap may crash.
4.  You are loading a network and the network topology does not
     match the "wiring" that you described to a static configurer.
5.  You have bad hardware.

If the number <n> in the message is small then you are likely to
be having troubles with the first bytes of code on the root transputer.
Suspect 1 or 3.  If the number is quite large (a reasonable proportion 
of your boot file size) and you only have one processor then suspect
RAM size problems.  If you have a network and <n> is quite large then 
suspect 4.

There are several tools that can help debug your problem.
A "worm" program will map out your network, including C004 connections,
and allow you to check your network topology.  A memory test program 
can help you find bad hardware.  INMOS (in the US at least) has a set of 
programs that do this called the "Checkout Programs".

Even when using a static configurer, it should be possible to
improve the server to give a better message when the bootstrap fails
to load a network.  Given knowledge about how the configurer works, the
server should be able to pinpoint the processor or connection that is missing.
I guess everyone has the source of the server.  If someone at INMOS was
willing to release the gory details of the configuration magic...