Jan Wolter
UnixPapa.com: A Ma & Pa Unix Shop
Visit UnixMama.com      Email Me
Contract Software  

Free Software
Orville Write

Tech Publications
Unix Notes
PBN Solvers
Grex Notes


Other Publications
Great Green Room
Solitaire Solvability

Forty and Eight
Right Side Up

Conference Links
Starting Grid

Et Cetera
Rx Burns
World Tour
Campus Towers
SUV Rant
Zealot Quote

E-Mail Me
Join White-List
Send Mail

Jan Wolter died on January 1, 2015, from complications of influenza.

• His obituary is here and here.
• His online guestbook is here.
• His Facebook page is here.
• There is a bench in memory of Jan, located in Gallup Park in Ann Arbor, in the sandbox next to the canoe livery. Mark Conger organized a people who planned it and put it there. Jan's next of kin are happy that the bench gets a lot of use.

You can reach Valerie Mates, Jan's life-partner, by using this form to send a message.

Contract Programming

I work as a freelance software developer. Mostly I do Unix systems programming, complex integrated web systems, and communications systems. Look me up if you need some high-quality Unix software development done. My partner at UnixMama.com does similar work.


Web Paint by Number is an on-line puzzle community where people create and solve a type of Japanese logic puzzle known as nonograms, griddlers, or paint by number puzzles. It's been very successful both as a sophisticated programming project and as a vibrant on-line community.

Politaire is a a solitaire card game site that allows you to modify game rules extensively. It's written entirely in Javascript and thus runs entirely in the user's browser, with virtually nothing done on the server side.

The Great Green Room is a blog / essay site where I publish non-technical articles on any topic that captures my interest, including global warming, gay marriage, Thomas the Tank Engine, religion, hot water heaters, and physics.

The Pro-Both site promotes an approach to the abortion issue that is both pro-choice and pro-life and epitomizes my tendancy to argue both sides of any issue.

Open Source Software

Mod_auth_external is an Apache module for using external programs to do authentication. I am the current maintainer of this, and the author of the related pwauth program for doing web authentication out of Unix shadow password files, as well as mod_authz_unixgroup, a module for doing access control based on unix group membership.

Pbnsolve is a high performance AI program for solving paint-by-number puzzles. It was originally designed to validate puzzles for my webpbn site.

Backtalk is a sophisticated open-source web-based computer conferencing system developed by Steve Weiss and I. Backtalk is used on several systems. It's spinoffs include Booktalk, a conferencing system for schools and libraries, and Fronttalk, a command-line interface cloning Picospan.

Orville Write is a much enhanced freeware version of the Unix write as used on Grex and M-Net.

Party is the fine old Unix chat program used on Grex and M-Net.

Gate is a text-gatherer, sort of a light-weight text editor typically used with Picospan, Yapp or Fronttalk conferencing systems.

Cursive is a program I wrote in 1987 to generate ASCII text banners in a rough cursive font.

Technical Publications

My Javascript Madness pages discuss various topics relating to the joy and agony of Javascript programming. There is lots of discussion of browser incompatibilities in mouse and key event handling, and a smattering of other topics.

My Survey of Paint-by-Number Puzzle Solvers examines a large number of AI tools designed to automatically solve paint-by-number puzzles and compares their performance.

My Unix Incompatibility Notes document some portability issues in commonly used C-language libraries under Unix.

A Guide to Web Authentication Alternatives is a detailed technical discussion of different schemes for authenticating users at web sites.

The Grex Staff Notes describe several aspects of the Grex public-access computer system, including a tour of the hardware, discussions of security goals and privacy policies, and technical descriptions on the kernel blocks and password database.

About the Author

Valerie and I have a three children, Arlo, Kendra, and Corbin.

Once upon a time I was a professor of Computer Science at Texas A&M University, doing research in Robotics, Artificial Intelligence, Computer-Aided Design and Computational Geometry.

I used to be an active participant in a number of virtual communities, having served on the staff of M-Net and Grex and served on the Grex board.

I also used to volunteer regularly for the Ann Arbor Parks & Recreation Department's Natural Area Preservation group doing mostly prescribed burns and invasive species removal.

Seconds of Fame

I've given testimony against Michigan's Internet censorship law in Federal Court. (A written draft of the testimony is available.)

I have an Erdös number of 3 (Erdös, [Alon | Aronov | Chung | Moran | Odlyzko | Pach | Pollack | Szemeredi | Yao], [Bern | Guibas | Hershberger | Suri], Wolter).

I've been quoted on Car Talk (though I didn't actually say the "yada yada yada" part). I'm also quoted in several on-line collections of "famous" quotations.

The first President Bush once signed a document honoring me for my cleverness.

Silly Stuff

Flixel is a simple "Lights Out" game that was originally written as a simple demonstration of Javascript programming. It acquired some features, but is still pretty simple. Flood-It started life the same way and suffered similar enhancements.

One of my early experiments with web technology back in 1995 was a sequence of pictures from my World Tour, which addressed the age old question ``Does travel really broaden you, or just narrow the world?''

In an (extended) moment of dementia and boredom, I compiled Grover's Guide to Campus Phallic Symbols. I promised never to do anything like that again, and have so far succeeded.

Grover's Guide to Auto Buying laid down the law for SUVs, minivans and pickup trucks.

For those of us who tire of looking at web pages full of moving images, busy backgrounds, and rambling text, I have developed a boldly new and totally innovative web technology: blank web pages. I can now offer blank web pages in black or white for those absolutists amongst us, and in eye-soothing shades of yellow and violet.


Sadly, the quantity of spam that I receive has risen to a level where E-mail had ceased to be an effective communication medium for me. I found I had to tell clients to phone me when they had sent me an important E-mail, so I would know to search through my spam for it. Stock spam filters weren't catching enough for me, and I didn't care to spend my time trying to build better ones. So, regretfully, I've switch to a white-listing approach, where only messages from E-mail addresses on my white-list appear in my primary mailbox.

This does not, however, mean I don't want to read mail from new people. I've provided a web form from which you can add yourself to my white-list. If you'd like to talk to me, please white-list yourself and send me E-mail. I'd be happy to hear from you.

Jan Wolter Mon Nov 1 13:33:30 EDT 2010