In-kernel web server

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An in-kernel web server is a (possibly limited) HTTP server that runs in kernel space or equivalent. Also called "accelerator".

Contents 1 Benefits 2 Drawbacks 3 Implementations 4 See also 5 References

[edit] Benefits

• Performance. The path taken by data from disk to network. Proper asynchronous zero-copy interfaces would make this available from user-space.
• Scalability with respect to number of simultaneous clients. Event notification of comparable scalability seems impossible in user-space¹.

[edit] Drawbacks

• Security
• Portability. Every kernel needs a specific implementation.
• Reliability. Failure in the webserver may crash the OS.

[edit] Implementations

• Solaris/NCAkmod
• HP-UX/NSAhttp
• Linux/khttpd
• Linux/TUX
• Windows NT/http.sys (part of IIS)
• SPIN/http
• OpenVMS/WASD.trap

[edit] See also

• comparison of web servers

[edit] References

• Note 1: CITI_TR_00-4
• High-Performance Memory-Based Web Servers: Kernel and User-Space Performance. Philippe Joubert, Robert B. King, Rich Neves, Mark Russinovich, John M. Tracey. IBM. T. J. Watson Research Center