Re: Ethernet card?

[toh@freenet.Victoria.BC.CA (Marc Sira)]

In our last episode, mvgfr@netcom.com (Marc Farnum Rendino) said:

>On Wed, 9 Oct 1996 12:16:12 GMT, Marc Farnum Rendino
>(mvgfr@netcom.com) wrote (<mvgfrDz0Cr0.L49@netcom.com>):
>
>I meant to mention another idea. I'm sure I'm not the first, but maybe
>it's time to think about it again - SCSI Ethernet boxes. The code to
>use one on a IIGS (or maybe even a IIe!) shouldn't be that different
>than on a Mac.
>
>Thoughts?

I think this is the way to go. I have an Asant� Mini EN/SC that I
bought for under $50, and drivers for it on my Powerbook Duo. At some
point I'm going to have a go at writing a device driver for it on my
Linux box at work. I obviously don't need to use such a device under
x86 Linux :) but this would be in preparation for a GS driver (so far I
have neither the tools nor the expertise on the GS; also, the Linux
generic scsi interface is quite nice, which gives me an easy foundation
that I already understand to start from). I haven't yet contacted Asant�
about technical information, but this is my plan. If they turn out to
be recalcitrant about giving this out, there are other several other
companies who make similar adaptors (Dayna, possibly Farallon, and
others). They're sold used on the misc.forsale.mac-specific groups
fairly frequently.

I get a maximum of about 80KB per second with FTPs on a 100MHz PPC Powerbook,
even with the Mac's cooperative multitasking and the EN/SC's drivers running
in (ick) 68K emulation. This is pretty respectable, considering the
circumstances (for comparison, I get way over 500KB per second from a crappy
16-bit ISA ethernet card in a 100MHz Pentium running Linux, but only about 60KB
per second on the same machine in the cooperative multitasking environment
of Windows 3.1 or 95 (your choices are yuck, or yuck). I've no idea what
sort of throughput one might expect from the GS - if a decent DMA driver could
be written, it might actually be respectable. :)

The only issue I can think of with such a driver on the GS is that the
Ramfast appears to have specific device support built into the ROM, and
this might interfere with an unexpected device like a communications
adaptor. The more generic Apple HS SCSI might be better suited, though I'm
sure it has its own issues. The EN/SC on the Mac requires two drivers; one
ethernet driver resource (probably something of a stub to plug into the
existing network support on the Mac) and one SCSI driver that loads as an
extension. I've also noticed that it apparently predates SCSI-II, and
doesn't report itself to the host as a nice SCSI-II COM device (it has
garbage in the device type field).

I can actually think of one other issue - the Appletalk support on the GS
is likely to be totally tied to the Localtalk port, so providing Ethertalk
support with a third-party driver might be tricky. Basically the problem is
that this might require rewriting much of the GSOS networking code from the
ground up, to get a nice layered network model you can work with. Perhaps
someone familiar with how Localtalk is done on the GS could comment?

I imagine the main desire for most people is to have other protocols
supported, though (TCP/IP).

I don't know how much I can offer in the way of writing an actual GS driver
for this thing, but I think I do have a good chance of sussing out the API
for Linux, and I'd be happy to give anything I come up with to a GS
developer. All I need now is time to work on it. :O

-- 
Marc Sira			   |
{ub675,toh}@freenet.victoria.bc.ca | "Your god drinks...p-p-peach nectar!"
{aa,xx}382@freenet.carleton.ca	   '