Poul-Henning Kamp () is a Danish computer software developer known for work on various projects including

FreeBSD FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...

and

Varnish Varnish is a clear Transparency (optics), transparent hard protective coating or film. It is not to be confused with wood stain. It usually has a yellowish shade due to the manufacturing process and materials used, but it may also be pigmente ...

. He currently resides in

Slagelse Slagelse () is a town on Zealand (Denmark), Zealand, Denmark. The town is the seat of Slagelse Municipality, and is the biggest town of the municipality. It is located 15 km east of Korsør, 16 km north-east of Skælskør, 33 km south-east of Ka ...

, Denmark.

Involvement in the FreeBSD project

Poul-Henning Kamp has been committing to the

project for most of its duration. He is responsible for the widely used MD5crypt implementation of the

MD5 The MD5 message-digest algorithm is a widely used hash function producing a 128-bit hash value. MD5 was designed by Ronald Rivest in 1991 to replace an earlier hash function MD4, and was specified in 1992 as Request for Comments, RFC 1321. MD5 ...

password hash algorithm, a vast quantity of systems code including the FreeBSD GEOM storage layer, GBDE cryptographic storage transform, part of the UFS2 file system implementation,

FreeBSD Jail The jail mechanism is an implementation of FreeBSD's OS-level virtualisation that allows system administrators to partition a FreeBSD-derived computer system into several independent mini-systems called ''jails'', all sharing the same kernel, with ...

s, the implementation of the

malloc C dynamic memory allocation refers to performing manual memory management for dynamic memory allocation in the C programming language via a group of functions in the C standard library, namely , , , and . The C++ programming language includ ...

library call, and the FreeBSD and NTP timecounters code, and the interface with David Mills.

Varnish cache

He is the lead architect and developer for the open source Varnish cache project, an HTTP accelerator.

Dispute with D-Link

In 2006, Kamp had a dispute with electronics manufacturer

D-Link D-Link Systems, Inc. (formerly Datex Systems, Inc.) is a Taiwanese multinational manufacturer of networking hardware and telecoms equipments. It was founded in 1986 and headquartered in Taipei, Taiwan. History Datex Systems was founded i ...

in which he claimed they were committing NTP vandalism by embedding the IP address of his NTP servers in their routers. The dispute was resolved in April 2006.

Other

A post by Kamp on the FreeBSD mailing lists is responsible for the popularization of the term ''bike shed discussion'', and the derived term ''bikeshedding'', to describe Parkinson's law of triviality in

open source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

projects - when the amount of discussion that a subject receives is inversely proportional to its importance. Poul-Henning Kamp is known for his preference of a

Beerware Beerware is a tongue-in-cheek software license with permissive terms, which grants the right to do anything with the source code, assuming the license notice is preserved. Description Should the user of the code consider the software usefu ...

license A license (American English) or licence (Commonwealth English) is an official permission or permit to do, use, or own something (as well as the document of that permission or permit). A license is granted by a party (licensor) to another part ...

to the

GNU General Public License The GNU General Public Licenses (GNU GPL or simply GPL) are a series of widely used free software licenses, or ''copyleft'' licenses, that guarantee end users the freedom to run, study, share, or modify the software. The GPL was the first ...

(GPL).

Publications

Poul-Henning Kamp has published a substantial number of articles over the years in publications like

Communications of the ACM ''Communications of the ACM'' (''CACM'') is the monthly journal of the Association for Computing Machinery (ACM). History It was established in 1958, with Saul Rosen as its first managing editor. It is sent to all ACM members. Articles are i ...

and

ACM Queue ACM ''Queue'' (stylized ''acmqueue'') is a bimonthly computer magazine, targeted to software engineer Software engineering is a branch of both computer science and engineering focused on designing, developing, testing, and maintaining softwar ...

mostly on the topics of computing and time keeping. A selection of publications:
USENIX ATC 1998 FREENIX track, "malloc(3) Revisited"

* ttps://web.archive.org/web/20050916085901/http://www.acmqueue.org/modules.php?name=Content&pa=showpage&pid=170 ACM Queue: Building Systems to be Shared Securely
ACM Queue: You're doing it wrong

ACM Queue: A Generation Lost in the Bazaar

Communications of the ACM 2011: The Most Expensive One-Byte Mistake

Communications of the ACM 2011: The One-Second War

References

External links

people.freebsd.org homepage

phk.freebsd.dk homepage

Blog in Danish

Another blog in Danish

Resolution of D-Link Dispute

Varnish cache
{{DEFAULTSORT:Kamp, Poul-Henning 1966 births Living people Danish computer programmers Danish computer scientists Free software programmers FreeBSD people Articles containing video clips People from Slagelse