Thread Library used in Slack and Linux

As i know, there are 2 implementations of thread library in Linux today.

one is called New Generation POSIX Threads (NGPT) library created by a group at IBM and Intel, led by Bill Abt at IBM in May 2001.

Another is called Native POSIX Thread Library (NPTL) created by Ulrich Drepper (red hat) and Ingo Molnar (also of Red Hat) in September 2002.

So which implementation is used in latest Slackware Linux 9.1??
How about the kernel 2.6.1? Which implementation is adopted in kernel 2.6.1?

And which implementation is prefer by Linus? Which implementation will likely to become the standard of Linux?


Please refer to this link:
http://www.onlamp.com/pub/a/onlamp/2...ds.html?page=2


Thanks for help.

As far as I'm aware Kernel 2.6 supports both, but NGPT is the preferred model.