At Wed, 25 Jan 2006 16:34:14 -0300, Leonardo Pereira wrote: > As I know, those interfaces already exists.
Gianluca's proposal is to expose these interfaces directly at the syscall level. Currently, the mechanisms are available via the appropriate device object. > So, I didn't understoo your "we > shouldn't add such interfaces to Mach". I do not understand why someone > would like to use IPC if we have an alternative that is faster than IPC. > This is not related to a good or bad IPC, but the use of good > mechanisms. The sole motivation should not be performance. One of the advantages of an object-based system is that inter-object dependencies must be made explicit. This makes object relationships clearer and in doing so reduces, in my experience, the number of inter-object dependencies. The net result is, hopefully, a decrease in complexity and an increase in robustness. To achieve this, I think a microkernel should strive to have a single system call, namely, IPC. Everything else should be built as an object on top of that to which users invoke a capability naming the object. That an object happens to be implemented by the kernel is irrelevant. That the IPC implementation is slow is, I agree, a problem. This problem should be fixed at the IPC level or shown that this cannot be done in a general way. Fixing Mach IPC will prove difficult: it works well when memory is near CPU speed. L4 and EROS have shown that this result need not be a categorical rejection of IPC based systems: different IPC models can be fast. Thanks, Neal _______________________________________________ Bug-hurd mailing list Bug-hurd@gnu.org http://lists.gnu.org/mailman/listinfo/bug-hurd
