As well as the Unix multiprocessing model involving heavyweight processes, which is of course part of the standard Linux kernel, there are several implementations of lightweight processes or threads. Recent kernels implement a thread model, kthreads. In addition, there are the following packages available for Linux.

• GNU glibc2 for Linux has optional support for threads. The archive is available from the same place as glibc2, ftp://ftp.gnu.org/pub/gnu/

• In sipb.mit.edu:/pub/pthread/ or ftp.ibp.fr:/pub/unix/threads/pthreads. Documentation isn't in the package, but is available on the World Wide Web at http://www.mit.edu:8001/people/proven/home_page.html. Newer Linux libc's contain the pthreads source. The GNU Ada compiler on ftp://metalab.unc.edu/pub/Linux/devel/lang/ada/gnat-3.01-linux+elf.tar.gz contains binaries made from that source code.

• In ftp://ftp.cs.washington.edu:/pub/qt-001.tar.Z is QuickThreads. More information can be found in the technical report, available on the same site is /tr/1993/05/UW-CSE-93-05-06.PS.Z.

• In gummo.doc.ic.ac.uk/rex/ is lwp, a very minimal implementation.

• In ftp://ftp.cs.fsu.edu:/pub/PART/, an Ada implementation. This is useful mainly because it has a lot of Postscript papers that you'll find useful in learning more about threads. This is not directly usable under Linux.

Please contact the authors of the packages in question for details.