Re: TCP/IP connection

[dempson@actrix.gen.nz (David Empson)]

BabarStCyr <babarstcyr@aol.com> wrote:

> Hi World2
> 
> About TCP/IP, Apple2 8bits and GS.
> 
> For world8:
> I got a odd idea. Since in Apple 2c the AppleTalk entry point
> will be never used, what do you think to modify rom to replace
> this entry point by a udp/ip tiny stack with a mini tftp to boot
> over network (this net can be simply a linux box) ?

The AppleTalk firmware only exists in one version of the IIc firmware
(the "UniDisk 3.5" version).  It is not large - I haven't looked at it
in detail, but I'd be surprised if it is even 512 bytes.  There is
probably a fair amount of unused ROM space that could be pinched, but
most of this would have been used up in the memory expansion version of
the IIc.

You then have the problem of a physical network connection.  Would you
use SLIP or PPP via a serial port at 19200 bps (or less)?  The only
other option is the SmartPort (disk interface), which would require an
external hardware box to convert the hardware to something useful, and
software to drive it in the IIc.

Next problem: assuming you could boot the IIc via some kind of IP
network, where do you put the full TCP/IP stack when you have booted?
There is no area in memory where it could reside without breaking
existing software.  The best you could manage would be to reserve
auxiliary memory, leaving you with a 64K IIc.

(One possibility would be an Applied Engineering Z-RAM, in which you
could steal one or more banks, but compatibility with some applications
would still be compromised, and this would be a rather small target
market.)

I don't see any way in which a general purpose TCP/IP implementation can
be done on an 8-bit Apple II, at least not without doing the vast
majority of the code on a peripheral card (e.g. emulate the API of the
Apple II Workstation Card), and that wouldn't work on the IIc anyway.

A software implementation of TCP/IP is certainly possible, but it would
have to be a limited environment, working with specially written
applications, or perhaps working in conjunction with an existing shell
(e.g. a BASIC.SYSTEM plug-in) and imposing memory restrictions.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand