Russell King - ARM Linux wrote:
>
> On Tue, Jun 19, 2001 at 05:11:23PM -0400, Jesus Molina wrote:
> > I am using an ebsa285 in add-in mode to access a IDE hard disk. This IDE
> > hard disk is also accessed by the host processor (pentium3 running linux).
> > I am able to acces the PCI, and to access the IDE hard disk if I change
> > the interrupt from the command line, but:
>
> I would strongly advise against this - its a recipe for total disaster.
> There will be no arbitration between the two processors for the IDE
> interface, and two requests going to the drive at the same time could
> cause any number of weird effects, maybe even data corruption.
>
> If you want to do this, then you need a communication path between
> both processors that locks one out while the other is accessing it.
I have seen some sort of a successful project to do this sort of thing
with SCSI devices. SCSI is a lot more straightforward - I mean, a host
adapter is just another device on the bus - but there's still issues to
resolve with regard to arbitration of controll over the actual device.
I don't remember much more than that, just saying that there may be
some work out there already that could be applied to this.
- Eric
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