I used to run the computer player named Zippy (see comic strips) on chessclub.com and freechess.org, and I wrote the code that interfaces him to those servers. You can run your own computer player on any ICS-compatible chess server using any chess engine that XBoard and WinBoard support. See the documentation that comes with XBoard and WinBoard; at this writing it is in a separate file named zippy.README, but it may eventually move into the manual. Please read the documentation instead of emailing me questions about Zippy. I probably don't remember the answers anymore.
Zippy does not work on Yahoo Chess, MSN Gaming Zone, WCN, or other non-ICS-compatible chess servers, and I do not have any software or knowledge about how to put a computer player on those servers.
Using a computer to choose your moves on a chess server is considered cheating unless your account is on the computer (C) list. Read "help computer" on your favorite server for details on their policy.
An alternative to Zippy that some people use is icsDrone. I'm told this is a newer version of what used to be called RoboFICS. I've never used either program and can't help with any questions about them.
On April Fools Day 1993, a new chess computer called Norm joined the Internet Chess Server. Norm's chess skills were rather weak, but he had another talent that gained him a lot of attention: Whenever a user shouted one of Norm Peterson's straight lines from the Cheers TV show, Norm would automatically shout back the response.
After about a month of listening to people shouting at Norm and Norm shouting back from his limited repertoire of responses, I started to get quite tired of it. But instead of complaining as any sane person would, late one evening I decided to bring up my own computerized shouting machine to compete with Norm and reduce the whole phenomenon to absurdity. This was the genesis of Zippy.
I grabbed a copy of the Zippy the Pinhead quotes database from MIT, as distributed with GNU Emacs. XBoard already had the necessary ICS interface and message parsing code, so after about an hour's hacking on it, I had a program that would respond to any shout from Norm with a Zippy quote.
Zippy the Pinhead is a satirical, surreal comic strip that appears in the San Francisco Examiner and about 100 other newspapers worldwide. Most of Zippy's remarks are non sequiturs to begin with, and they seem even more bizarre when taken out of context. I thought they would provide a suitable counterpoint to Norm's endless repetition of the same jokes. As an extra throw-in feature, I also made Zippy respond if someone shouted his name or talked to him directly.
The response to Zippy was quite different from what I expected. Lots of ICSers, both those who had read the comic strip before and those who hadn't, thought Zippy's remarks were hilarious and asked me to keep him around. On the other hand, lots of other ICSers learned to use the "censor" command! I ended up spending quite a few more hours refining Zippy and adding new features, including a timer that prevents him from responding to shouts more often than once per minute, and a remote control so that I can make him shout remarks of my own invention.
I got many requests to teach Zippy to play chess. For quite a while I resisted because I didn't want to put any more work into Zippy. But one day in September I got bored and decided to see how long it would take to hack in the necessary code to make Zippy play. Since XBoard already had code to interface to GNU Chess and code to interface to the ICS, it couldn't be too hard. In fact, it turned out to be much easier than I had expected, and within a couple of hours, the computerized Zippy played his first game on ICS. After a few more days of hacking, including some minor bug fixes to clock code in GNU Chess, I had Zippy working well.
Zippy plays chess using the latest released version of GNU Chess, with a minimal number of bug fixes. I don't have time to hack on GNU Chess, neither to improve its play nor to make it more appropriately pinheaded. Actually, I feel it's a nice irony that Zippy plays chess quite well while making the same absurd remarks as always.
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These days Zippy is semi-retired, but his offspring are lively and growing. The Zippy code is included in current distributions of both XBoard and WinBoard. Many chess programs on ICC and FICS use this code. And they are not all GNU Chess clones! The authors of Ferret, Crafty, and other original chess programs have mated their chess programs with Zippy to connect them to the chess servers. Most of Zippy's children are more mild-mannered and don't like to shout. But Zippy lives on in their genes! <:->