Quantitative System Performance  
   Introductory text on analytic computer performance models. Complete text is available as searchable PDF. Published in 1984.
   http://www.cs.washington.edu/homes/lazowska/qsp/

The Art of Computer Systems Performance Analysis  
   Raj Jain's 1992 text provides a comprehensive introduction. His site includes lecture notes for many chapters (but not all) and errata.
   http://www.cis.ohio-state.edu/~jain/books/perfbook.htm

University Classes on Computer Performance  
   Web sites for academic classes on computer performance. Typical contents include syllabi, readings, homework, and lecture notes. Useful to students, instructors and practitioners who want to review the basics.
   http://www.frontrunnercpc.com/info/classes.htm

Internet Speed Boost Solutions  
   Modem tweaks and browser tips to speed up Internet access. Reports web accelerator software options which claim full optimization.
   http://www.inboost.com/

ATL-CSIM: System Simulation and Modeling Tools.  
   Lockheed Advanced Technology Labs' CSIM is a general purpose discrete-event simulator for block diagram oriented systems. Graphical/interactive or text/batch simulations. Not to be confused with Mesquite Software's CSIM18, another simulation tool.
   http://www.atl.lmco.com/proj/csim

Stratton & English Software - Performance Specialists  
   Provider of Internet Software Services, specialising in Performance Investigations - including performance prediction, optimisation and testing.
   http://www.strattonenglish.co.uk

Future Star Services  
   Brief overview of some tools for performance measurement on UNIX systems.
   http://www.unixperformance.co.uk/tools.htm