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68000 Coprocessor on Apple Macintosh NUBUS Ethernet ?!


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Was busy cleaning some NuBus cards and noticed something weird on this card. I'm amazed it's there, as usually you will find something more a 68HC05 or 68HC11 performance wise, so it has to do some "heavy" processing.

 

Pictures attached for reference

 

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Close view:

 

IMG_5219.thumb.jpg.165434ec653bf842b9f46a93e259ffc8.jpg

 

What it is for ? Something like LRO / TCP Checksum Offload ? Does MacOS even support this ? I guess one can dump the ROM and have a look though...

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There was a thread about this pretty recently; TL;DR, the 68000 is for running A/ROSE, an experiment with trying to make Nubus cards easier to build by making them fiendishly complicated and overbuilt. (Yes, seriously, not joking.)

While in theory at least this ridiculously powerful blob of hardware would have allowed tricks like offloading whole parts of the protocol stack in practice it was never used anywhere close to its full potential.

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There is a measurable difference when using A/ROSE and the Apple NuBUS ethernet card.  My 040 accelerated IIci has noticeably faster transfer speeds when using the Apple NB card versus a Farallon.  I suspect the advantages are more pronounced on slower machines like the original Macintosh II.

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Other than speed, you'll find an 030 machine like the IIfx relatively unhindered when acting as a fileserver using one of these. With normal ethernet cards, a large appleshare transfer will slow other processes significantly, but with A/ROSE it's rather seamless.

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11 hours ago, Gorgonops said:

There was a thread about this pretty recently; TL;DR, the 68000 is for running A/ROSE, an experiment with trying to make Nubus cards easier to build by making them fiendishly complicated and overbuilt. (Yes, seriously, not joking.)

While in theory at least this ridiculously powerful blob of hardware would have allowed tricks like offloading whole parts of the protocol stack in practice it was never used anywhere close to its full potential.

Oh i didn't know A/ROSE actually ended up in production. Thats interesting, so A/ROSE is the "offloading" part. The hardware part doesn't seems overcomplicated (Looking at the PCB traces, the 68000 talks to the SONIC chip and NuBus circuitry). The software on another hand...

 

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5 hours ago, olePigeon said:

There is a measurable difference when using A/ROSE and the Apple NuBUS ethernet card.  My 040 accelerated IIci has noticeably faster transfer speeds when using the Apple NB card versus a Farallon.  I suspect the advantages are more pronounced on slower machines like the original Macintosh II.

I need to benchmark this on my IIcx !

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From reading what few docs there are about to what extent A/ROSE was actually leveraged by that card it sounds like the 68000 mostly acts as a sort of caching substitute for a DMA controller, there isn't really any protocol offloading per se, but considering how some of the structural defects in the classic MacOS can really make it suffer when trying to respond in real time to a peripheral every little bit probably helped.

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10 hours ago, Gorgonops said:

From reading what few docs there are about to what extent A/ROSE was actually leveraged by that card it sounds like the 68000 mostly acts as a sort of caching substitute for a DMA controller, there isn't really any protocol offloading per se, but considering how some of the structural defects in the classic MacOS can really make it suffer when trying to respond in real time to a peripheral every little bit probably helped.

If by chance you have thoses docs around, I would gladly take a look at them

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19 hours ago, Nathan_A said:

Does anyone know what the SIP sockets on these cards are for?

 

Well, they're labelled TC514400, and that's a DRAM chip.  ZIP wasn't an uncommon shape for DRAM in general, and the Toshiba datasheet for at least one of the TC514400 variants says it comes in 20-pin ZIP.

 

What, if anything, the card does with that memory, your guess is as good as mine.

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Hmmm. Well. I'll see if I can source some to stick in there. First test will be to see if it does anything deleterious. Second test, if I can get at some flavor of the developer toolkit & "NuBug", will be to see if it seems to actually do anything with the RAM.

 

I'm trying to put together a system that's a bunch of computing "platforms" in one box. Current slate is: PM8100/100 for PPC Mac, Radius Rocket for 68k Mac, Ethernet NB for 68k A/ROSE, and trying to get either a Nubus or 601 PDS PC compatibility card for x86 Win.

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@Nathan_A  Yes!  They're for ZIP RAM.  There's another thread somewhere on here somewhere where someone installed the RAM.  Unfortunately the forum is giving me problems and won't complete a search without a 504 time-out error. :(

 

If I remember correctly, it turns out the ethernet card will access system memory for use with A/ROSE.  It'll speed the card up little bit more by giving A/ROSE its own dedicated memory.

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19 hours ago, olePigeon said:

It'll speed the card up little bit more by giving A/ROSE its own dedicated memory.


Oh now I definitely, absolutely, need to find some ZIP RAM for my card! :) but seriously this is the kind of thing that would be kinda fun to benchmark. 

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On 3/24/2021 at 12:14 AM, Nathan_A said:

I'm trying to put together a system that's a bunch of computing "platforms" in one box. Current slate is: PM8100/100 for PPC Mac, Radius Rocket for 68k Mac, Ethernet NB for 68k A/ROSE, and trying to get either a Nubus or 601 PDS PC compatibility card for x86 Win.


 Neat idea!

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20 hours ago, olePigeon said:

Was there ever an LC PDS to NuBus adapter?  If you could stick a //e card in there somehow.


Not that I know of. In theory (albeit far out theory!) maybe something could be done through the 8100 PDS slot?

Apple made a converter for the 6100 Dos card that went from PPC601 PDS to 68040 PDS.


I don’t think there was ever a card that plugged into the 68040 PDS that gave you a 68030 PDS slot in either IIsi/SE30, LC I/II or LC III & above format.

 

I think the LC PDS //e card was compatible with the 68030 PDS up until the LC 575.  But it required 24-bit addressing.... so this thought exercise is probably all for naught since I’m fairly certain PPC Macs don’t have a 24-bit addressing option.

 

 

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There was a Nubus adaptor for one of the later Quadras, wasn't there? The one that shared a case with the 6100? (Which also has a Nubus adapter.) I think it's just an Apple ASIC on a board with two sockets, though.

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