Separating functionality from implementation.

Separating functionality from implementation.

Posted Nov 6, 2003 13:52 UTC (Thu) by brugolsky (subscriber, #28)
Parent article: The future of the Linux filesystem

Discussing semi-structured data, indexing, etc., seems to degenerate rapidly into "we're falling behind!" v. "not in my kernel!" I'm happy to see projects like Storage and Dashboard going at this in GNOME / Mono. Perhaps after *extensive* experience with a working implementation, the hard task of separating out the core functionality, figuring out what sort of assistance userland needs from the kernel (e.g., we already have DNOTIFY), and whittling down the userland side to flatten the web of shared object dependencies.

Unix has evolved other mechanisms for naming above the filesystem, e.g., the whole nsswitch subsystem, with pieces in libc, config files, nscd, Solaris doors, etc. It generally sucks (IMHO), but more-or-less works. In principle, gnome-vfs or Storage is not all that different from libresolv.

Linux POSIX threading used to be done entirely userland, and did about 90% of the job, slowly. After many years of experience with LinuxThreads, and spurred on by NGPT and Rusty Russell's FUTEX work, Ulrich Drepper and Ingo Molnar figured out what functionality needed to go into the kernel to get it right, and made it happen, within the limits of good taste.

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