On 01/26/2011 11:09 PM, Daniel Waddington - SISA wrote:

Hi,

Can someone briefly explain the basic differences between the current Fiasco kernel API and the Pistachio X2 API?

The current version of Fiasco is Fiasco.OC, which is no longer based on the extended V2 API: http://os.inf.tu-dresden.de/fiasco/features.html

The corresponding Pistachio feature list is available here: http://os.ibds.kit.edu/1956.php

Fiasco.OC is a capability based kernel meaning all kernel objects (including IPC "channels") are addressed via mappable capabilities, which reside in a task's address space. Pistachio X.2 works with a global namespace for all kernel objects, which means to avoid existence leaks you have to globally partition the thread namespace. Both Fiasco.OC and Pistachio implement UTCBs as the main mechanism for data exchange between user-level threads and the kernel, which effectively gives you a 32+ word register IPC. OC supports a quota-like kernel memory management mechanism, which as far as I know is still missing in Pistachio X.2. Otherwise, both kernels provide pretty much the same functionality (HW virtualization included).

Does this answer your question?

Best regards

Marcus