WTB: Applenet Card

[ried]

I'd love to pick up an AppleNet card someday. I know, rare as hen's teeth, but still. Putting this out there just in case.

[bmwcyclist]

That would be great if we can understand how it works and perhaps replicate it!

[ried]

stepleton has one. As far as I know, they are completely distinct from Ethernet and the software enabling it was never completed. It's a technological dead end, and these are really just historical artifacts at this point. I want one because I love the mystery of experimental, unfinished products like that.

[bmwcyclist]

stepleton has one. As far as I know, they are completely distinct from Ethernet and the software enabling it was never completed. It's a technological dead end, and these are really just historical artifacts at this point. I want one because I love the mystery of experimental, unfinished products like that.

understood. It would be great to get LOS on AppleTalk someday!!

[stepleton]

yes, I have Applenet. I reverse-engineered the adaptor board some years ago, and the schematic wound up on bitsavers:

https://www.bitsavers.org/pdf/apple/lisa/appleNet/Applenet_Schematic.pdf

You can find the KiCad schematic files and additional project notes here:

https://codeberg.org/stepleton/applenet

I got partway through reverse-engineering the card's boot ROM but didn't quite finish the job. Somewhere in the LisaList archives you can also find Ray spotting one of the items that puzzled me as a particular kind of CRC calculation. Regardless, it was getting to the point where you would also have to know what the built-in Z8 microcontroller did and also how to understand what the PAL was doing if you wanted to make more progress.

The card's boot ROM does some weird things, like overwriting the location in the Lisa's RAM where the main Lisa boot ROM puts a pointer to the video memory. That's a useful pointer! (The Selector uses it, among other apps.) It's not clear why it does that. My guess is that the AppleNet card is from earlier in the Lisa's development life when the boot ROM organised things differently.

@ried is correct that AppleNet is 100% a dead end. It may have some operational things in common with Ethernet --- it uses CSMA/CD, for example --- but it also seems to do what it does all in its own way. I'm aware of nothing else compatible ever being made, nor of any sign that this was ever a goal. I guess this is the same spirit that brought us Twiggy and Widget.

These days we have advanced tools that can do reverse-engineering very well, much better than I could (or can today)! Revisiting the code with those tools could be interesting --- but from a practical perspective there is is probably not much more that's important to know, in my opinion. (What remains are quite low-level implementation details, in other words.) You could point Claude at the code, schematics, and PAL equations and dump all the remaining low-level details here if you wanted to.

I guess what I'm saying is, though: would that be spoilers?

[jamesdenton]

https://www.bitsavers.org/pdf/apple/lisa/marketing/Lisa_Sales_Marketing_Binder_Feb84.pdf

Around page 35, or so, Apple mentions "modified their approach to networks". Competing standards had emerged (Ethernet vs TokenRing) and Apple mentions being "neutral" with their AppleBus (AppleTalk) as an interconnect and using gateways to connect to wider networks using whatever standard(s) emerged as the winner(s).

Maybe by the time that sales binder came out they realized leveraging "built-in hardware" across the entire product line was "good enough" to meet customer requirements at the time?