i386 vs SCO vs ESIX vs foo-ix?

[John Ioannidis]

Hello!

I have been using InterActive's 386/ix for some time, and I'm about
to upgrade to the new release. I wonder if I should go for it, or
I should consider the SCO or the ESIX offering. Here are my 
requirements:

- support of the Toshiba 5200/100
- *robust* TCP/IP and NFS
- good system documentation, so that I can 
  . add my own devices (mostly network interfaces) and 
  . build a new filesystem type

What level of technical support do those companies provide? I'm not
talking at the "how do I log on" level, but rather at the
"how do I change the MTU in the STREAMS driver for my home-brewed
network interface"? (BTW, the latter is a legit question, and 
I can't just ifconfig it with a different MTU!)

Finally, is there any chance that we can licence source code?
(we are a university and we have full AT&T SVR3.2 sources)

Thanks,

/ji

PS: InterActive/ESIX/SCO tekkies, are you listening?