On Sun, 2008-08-31 at 11:55 +0200, Neal H. Walfield wrote: > At Sat, 30 Aug 2008 14:02:40 -0400, > Jonathan S. Shapiro wrote: > > It strikes me that rebuilding a very large number of drivers as a > > precondition to success is probably not a good recipe. > > > > Is there any reason why the linux driver framework cannot be adopted > > directly by l4-ng? I do understand that user-supplied drivers are > > desirable, and I think that remains possible in all of the practical > > use-cases that have come up here. > > Although custom drivers offer the best potenial quality, writing new > drivers for all hardware is impractical. So there must be some reuse. > However, some reuse does not imply that all drivers must be reused. > That is, very common hardware or essential hardware can be provided by > native drivers and the rest by way of reuse.
I agree with all of these points. But this does imply that certain *interfaces* from Linux become mandatory: those that in SVR4 would have been called the "Driver Kernel Interface". This is ad hoc in Linux, but it exists. > This hair can be avoided by reusing Linux in its entirety. In this > case, Linux is run on a VMM and the new operating system makes calls > to the Linux driver instance. Two examples of this are Afterburner or > Xen. Both use a paravirtualized Linux instance. But if this is done, what is the advantage of having a microkernel at all? shap
