LISA

[Ray Arachelian]

der Mouse wrote:
>> Further, if you're serious about [building an IP stack for the Lisa],
>> you might want to go with PPP as that would be far easier to
>> implement and would run without requiring a SCSI card on a real Lisa,
>> as well as on the emulaor.
>>     
>
> (a) Surely you mean Ethernet, not SCSI?
>   

Actually, we do mean SCSI - there used to be a SCSI card for the Lisa - 
only worked under MacWorks, and there used to be a SCSI->Ethernet 
adapter.   (Much like there used to be parallel port ethernet adapters 
for PC's.)

Both the Lisa SCSI card and the ethernet<->SCSI adapter are quite rare 
these days, so it's not much of a solution.  However, the Lisa does have 
a pair of built in RS-232 ports, one of which can be used for appletalk 
(localtalk) so it can go as high as 230kbps.

Of course, it's very difficult getting the Lisa to sustain much of any 
serial conversation above 19.2, even with hardware handshaking, and 
leaving it enough CPU cycles to do much of anything else.  But then 
again, if you can build a TCP/IP stack for Lunix and Con-Tiki on C64's, 
it can be done on a Lisa too...

As as aside, there were lots of very strange things on SCSI busses back 
in the day.  Scanners were quite common, but there actually existed 
printers, and even video cards on SCSI busses. :-)   The SCSI video card 
and ethernet card were useful for compact Macs that had a scsi port, but 
no expansion slots.

The Lisa does have 3 expansion port slots, so it if you're going to 
build hardware, you could easily build an ethernet controller for it, 
but they would be quite expensive, and not very useful in terms of how 
much bandwidth you'd get out of them.  But serial ports are free as 
they're built in, so only the software half is needed.

> (b) SLIP would be substantially easier than PPP; in my experience, when
> you're using hardwired lines (as opposed to asymmetric dialup
> connections), it's also substantially more reliable.  
Very true.