DDE Linux26 in the Hurd

Henning Schild hschild at os.inf.tu-dresden.de
Thu Jan 28 11:01:20 CET 2010


On Wed, 27 Jan 2010 22:54:49 +0800
Da Zheng <zhengda1936 at gmail.com> wrote:

> > Yes, there is a physical limitation with the current approach. Our
> > more recent ideas however go more into a direction where a physical
> > IO manager provides applications with pre-configured virtual PCI
> > buses, so that we did not really hit this limitation yet, because
> > we provide for instance the NIC driver with a virtual PCI bus that
> > only contains the NIC.
> Why do you not just put all PCI devices in the logical bus (so the
> number can be larger than 32)? There should be no physical limitation
> for the logical bus and the current limitation is set by DDEKit
> itself. Of course, then you have to change the code in DDE Linux26,
> so it can scan more than 32 devices on the logical bus until it finds
> the right one or there is no such device at all.

The main idea is to let each driver run as a separate application.
Therefore applications using DDE usually do not need to access multiple
devices and the virtual bus contains only one device in that case.
Following this approach you would start multiple driver-servers (using
DDE) if you need drivers for multiple devices.
So instead of having one instance having 33 devices at its bus we would
suggest to run 33 instances each having one device at the virtual bus.


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