Nasta,

thank you for taking the time to write this - wonderful information!

On Mon, Sep 27, 2010 at 3:09 AM, Z N <[email protected]> wrote:
> Maximum data throughput on 10Base ethernet approaches about 800-900k
> bytes/second.

Well, the good thing is that it takes around 0.1s to fill up the main
memory of the original hardware at this speed :) Anyway, seriously
speaking - what I really had in mind is a replacement for the PPP over
serial connection setup which I currently run. Main use for me would
be non-throughput intensive applications like a small web server, web
clients and interactive applications like telnet.

> less than half if it's done by an ordinary 68008 CPU. Unless a very simple
> communication protocol was adopted, the ethernet would run quite slow and
> while doing that, bog down the CPU considerably.

I agree, that's why I thought a microcontroller based board would be
optimal, essentially hooking up a more powerful cpu to do the heavy
lifting and leave a very thin driver layer on the ql side. This guy
has a nice writeup which might serve as one possible starting point:
http://www.tuxgraphics.org/electronics/200606/article06061.shtml


> that a packet has been sent or received. Here we get back to the
> inadequacies of the ROM port - no interrupt line. There is one on the
> expansion port

Based on all the information from you and Miguel the expansion port
definitely looks like the way to go.

> DSMCL can over-ride any decoding internal to the QL, on ANY address.

This was really interesting stuff that defnitely was not in the
documents I found so far.

> which are actually used by the software to access these registers - if I
> recall correctly, it's 64 bytes at the very beginning, starting from address
> 18000.
"The Sinclair QDOS companion" seems to agree with you :)

> However, the choice of address is not straight-forward. Hardware like the
> TC, GC, SGC use some addresses in this area to decode their own on-board
> hardware. Unfortunately I do not recall off the top of my head exactly which
> ones but something about the top 256 bytes rings a bell.

Hopefully someone has the details on the addresses in use by those.

> 3) Mimic the OS initialization scheme using the initialization data normally
> found at the beginning of a (presumed) ROM in the ROM slot. It may be
> possible to do this by manipulating register values passed in the
> initialization of the external interface, but I would not recommend it as
> the init code is different in various OS versions - besides, what the OS
> does on init is quite well documented and not too difficult to emulate, so
> better keep things clean and compatible.

There seems to be a writeup on this in "The Sinclair QDOS Companion".
Don't know if the procedure outlined there still applies with the
newer ROMs, etc.

> Done!

With your instructions, easy as pie :)


Cheers,
Petri
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