HP doesn't make a lot of noise in the free software world, even if it is an actor and also a user for its own IT infrastructure. For example, all the incoming mail in HP goes through PostFix servers
#dig hp.com -t mx | grep MX ;; hp.com, type = MX, class = IN hp.com. 21m28s IN MX 50 cossmtp.hp.com. hp.com. 21m28s IN MX 50 palsmtp.hp.com. hp.com. 21m28s IN MX 20 postal.agilent.com. hp.com. 21m28s IN MX 10 envelope.hp.com. hp.com. 21m28s IN MX 10 letter.hp.com. hp.com. 21m28s IN MX 20 stamp.agilent.com. hp.com. 21m28s IN MX 30 cossmtpx.hp.com. hp.com. 21m28s IN MX 50 atlsmtp.hp.com. #telnet envelope.hp.com 25 Trying 188.8.131.52... Connected to envelope.hp.com. Escape character is '^]'. 220 envelope.hp.com ESMTP Postfix QUIT 221 Bye Connection closed by foreign host. #telnet letter.hp.com 25 Trying 184.108.40.206... Connected to letter.hp.com. Escape character is '^]'. 220 letter.hp.com ESMTP Postfix QUIT 221 Bye Connection closed by foreign host. #telnet postal.agilent.com 25 Trying 220.127.116.11... Connected to postal.agilent.com. Escape character is '^]'. 220 postal.agilent.com ESMTP Postfix QUIT 221 Bye Connection closed by foreign host.
Identically, for its institutional Web server, HP uses Apache as more than 15 millions of other sites.
#wget -S http://www.hp.com/ --15:09:45-- http://www.hp.com:80/ => `index.html.1' Connecting to www.hp.com:80... connected! HTTP request sent, awaiting response... 200 OK 2 Date: Fri, 05 May 2000 13:12:25 GMT 3 Server: Apache/1.3.9 (Unix) mod_fastcgi/2.2.2 [...]
Agilent (old-HP branch) uses also the free software Perl for CAD as related at http://perl.oreilly.com/news/agilent_0300.html
HP also worked on the improvement of the proxy-cache Squid , as related at http://www.hpl.hp.com/techreports/1999/HPL-1999-142.html
In another domain, HP produces also documents to help convincing to the use of Open Soure Software, as this HP Labs report available on http://lib.hpl.hp.com/techpubs/2001/HPL-2001-233.html
A lot of HP people work on open source projects. They deserve a particular notice because, as in every open source project, their tenacious and constant comportment make these projects alive. Among them:
Port of the Linux kernel on IA-64 http://www.linuxia64.org/.
Major contributor of the Linux kernel port on Pa-Risc http://www.parisc-linux.org/.
Wireless Tools for Linux http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/Tools.html.
Projet HP imprimante jet d'encre http://hpinkjet.sourceforge.net/.
System Imager http://www.systemimager.org.