[vcf-midatlantic] Idea for an Exhibit - Novell

David Riley fraveydank at gmail.com
Sat May 26 07:40:50 EDT 2018


I've actually been working on some options for routing LocalTalk to Ethernet (including a MacIP gateway). The bottom line is that most modern WiFi/Ethernet devices can usually handle the protocols that go over Ethernet just fine (with some exceptions; there are features of some protocols that work much better over Ethernet than WiFi, particularly if they do funny things with MAC addresses).

Serial protocols are another matter. Ones that run over standard UARTs, like DECNet, are totally doable with a lot of new things. LocalTalk, on the other hand, made use of the SDLC mode in the 8530 serial chip used on the Macintosh, which is not something generally present on a lot of embedded devices. At that point, you're left with the options of interfacing an external 8530 (messy), bit-banging the serial (tough at the 230 Kbps used for LocalTalk, but sometimes doable), or making your own translator chip from a CPLD or FPGA (expensive).

One such project I've been working on is with the BeagleBone Black, which has two high-speed real-time coprocessors on the chip; those are quite suited to bit-banging the LocalTalk serial and passing it to the main CPU.

All of that, of course, comes before the software stack. The benefit of something like the BBB is that it runs Linux, so it can run netatalk, which already routes quite well between LocalTalk and EtherTalk (and can do the MacIP gateway as well). For something like an ESP32, you'd need to write your own embedded AppleTalk stack, which is not trivial.

FWIW, if you're looking to connect "AppleTalk to cloud", check out the forums at mac68k.info; Rob Braun has written what is essentially an AppleTalk VPN module for doing essentially that.


- Dave


> On May 25, 2018, at 18:39, Herb Johnson via vcf-midatlantic <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> 
> Itg's unlikely that a modern Ethernet or WiFi device, could perform the hardware and software protocols corresponding to even older networking standards, including Appletalk. I think such emulators would have to be built from the ground up. They are likely painful to build reliably and flexibly. Remember my concept - sufficient to "echo", handshake some packets - not a full emulation.
> 
> That said, I happen to know, AppleTalk did run "over Ethernet", through simple devices that physically routed AppleTalk traffic on the Ethernet wires. But the Ethernet devices themselves, ignored that "traffic" - probably saw it as bad packets, noise, etc. This was done to put Apple printers on Ethernet networks - except of course any Ethernet-owning device had zero access to Apple printers, and Apple computers had zero access to Ethernet devices.
> 
> People who buy Appletalk printer to Ethernet devices, thinking they are their magic road to "internet their Macs", find out eventually that won't happen.
> 
> So it may be possible, for a few network protocols to share the same cable. But they would not be "interoperative" - that calls for hard work. Companies and careers were made, doing such things in the era. We poor hobbyists live in the shadows of such giants. The amazing thing, would be to get some ancient networking protocol to work AT ALL. I suggest humility, and avoid the simple notion "I can plug it in - so it will work, or could".



More information about the vcf-midatlantic mailing list