Subject: Re: SCSI network
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Todd Whitesel <toddpw@best.com>
List: tech-kern
Date: 09/30/1999 23:53:46
> I'm contemplating using SCSI interfaces as a networking medium. Does
This would be very cool ... potentially faster than 100bt, cheaper than
giga-ethernet.
And for machines that will never have 100bt hardware, it would allow you
to get at them quicker by using another machine as a router.
> anyone have any thoughts on where I should look for (a) convincing a
> machine that it should speak on other than ID 7 or (b) convincing a
Some machines have a eeprom/nvram setting for the host's SCSI ID, but
I expect that this is only used by the boot firmware. You'd probably have
to UTSL to find the relevant kernel code.
> Oh, it is also important that both hosts be able to speak to disks on
> the bus. (Yes, I do intend to make sure they use disjoint subsets of
> the drives present. :-)
This is definitely possible; it's been done before. Back in the heyday of
the Apple II in elementary schools, you could buy a SCSI card from CMS
peripherals that would let you share one hard drive among multiple hosts
on the same bus. As you'd expect, read-only partitions were accessible to
all hosts and writable partitions were exclusive to one host.
I'm pretty sure they used an NCR 5380 with smarter host software. All
the Apple-branded SCSI hardware from that era did.
Todd Whitesel
toddpw @ best.com