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Free Software from the desk of David Harris.


Welcome to my free software home page. Currently this consists of my work on free software projects done mainly in conjunction with my job as Principal Engineer of drh.net. Feel free to look around and see if anything is useful to you.

~ David Harris <dharris@ >


  • Selective SMTP relaying based on POP authentication for qmail
    Smtp-poplock is a simple system to only allow hosts who have authenticated via the POP3 server to relay mail using qmail. This does not require patching the POP or SMTP servers, but is implemented by a few programs which cleanly interface into the system, and can work with most any POP or IMAP server.

  • Production quality UW-imap server Maildir support
    The University of Washington IMAP server by Mark Crispin, one of the most popular IMAP servers, does not have built-in Maildir support. There is a patch which adds in a Maildir driver, but it falls short of a workable solution in a few ways. This page details a few patches which clean up a few issues and make the UW-IMAP server fully workable with Maildirs and qmail.

  • Virtual user interface for UW-imap server
    Patch to the University of Washington IMAP server to allow authentication of virtual users by a backend C function, which may read user data from a database. This securely allows single-uid POP3 and IMAP mail setups with the UW-IMAP server.

  • Fastforward-idx for qmail
    Fastforward-idx is a patch to the qmail accessory program fastforward, which adds in qmail-local functionality and allows each user to have their own alias file, with the goal of replacing .qmail files for per-user mail configuration.

  • UNIX/DOS newline translation for Samba
    This patch to Samba version 1.9.16 adds newline translation between the UNIX and Dos/Win95 worlds. As files are transfered their newline format is automatically detected and changed so that the dos world is happy with the CRLF and UNIX has LF.

  • My CPAN directory
    This is my directory on CPAN, the Comprehensive Perl Archive Network. Right now I've only published one Perl module, DB_File::Lock, but more will probably come.

  • Simple RBL (spam filtering) false-positive test
    This document describes a simple test that was done to determine if the RBL spam-prevention utilities returned too many false positives or not to be deployed into production on my server. I present the data. You may make your own choices.

  • DiffEq Matrix Exponentiation Explorer
    A web software tool to explore the accuracy of numerically solving linear homogeneous differential equations using matrix exponentiation. Possibly useful for hands on demonstration of the cool tool that matrix exponentiation is.

  • Linux Software RAID readonly-mode patch
    This patch enhances the Linux Software RAID drivers so that a root mounted raid virtual device can be properly shut down. A mathematically pure solution to the root mounted raid mdstop problem. (Currently not posted.) (This will not be posted.. the latest kernel raid driver obsoletes this patch.)

Other stuff
Why the name davideous.com?

Mr. Lindauere, one of my teachers in seventh grade, gave me the nickname "Davideous". I don't know why it stuck with me, because I changed schools after that year and no one ever calls me davideous. My thanks to Mr. Lindauere -- he was a cool guy and a great teacher.

Shameless panhandeling

If you are able to use any of the stuff here, and you happen to be moved to the point of thinking "hey, i wanna do something nice for this guy", then you might be interested in looking at my amazon.com wish list. Or perhaps send me a note saying "thank you", which are always good to get. Nuff said. :-)