Update Jun 20th 2019. I found a good link that explains pulsar at the Chess Programming Wiki .
Pulsar version 2009(Mac, Windows, and Linux) can play Chess and the variants Crazyhouse, Atomic, Giveaway, Suicide, Loser's, Three Checks, Chess960, Shatranj, 2King, as well as various setboard wilds. Version 2007(Windows and Linux) will play all but Shatranj and Chess960. The latest version supports analysis mode in Atomic, Loser's, Giveaway/Suicide, Crazyhouse, 3Checks and regular chess.
There is also an iOS version for tablets and phones at Pulsar Chess Engine - US App Store link. Levels of difficulty can be set within the app. It also plays regular chess and difficulty can be set for that too. The variants it plays are Chess960, Crazyhouse, Atomic, Three Checks, Giveaway(similar to FICS Suicide) and Loser's.
Update - now(as of Jan 2019) an Android version of Pulsar if anyone wants to play Crazyhouse, Atomic Chess, Loser's Chess, Three Checks or Giveaway(also known as Suicide) on Android as well as Chess. Pulsar on android We have a support page for the apps which also has piece rights stated.
For Pulsar to play Atomic Chess with fics rules use the word fics as a program argument. This applies to older versions as well. pulsarscoop2 link below for more info.
lanternbugs at gmail Dot com
additional: pulsar2009-9b is expected to work with the books from pulsar2009-9a-release package. the licence also applies to any packaging of pulsar2009-9a.exe or pulsar2009-9b.exe with any combination of books that are wanted to be included from the 9a package ( with teh name changed to 9b for the 9b package). The release is understood to be the executables, 9a or 9b, and any combination of the books or bat files, or none, which are optional.
This release plays normal chess, fischer random, shatranj, 3checks, atomic, crazyhouse, losers, 2kings, suicide/giveaway and shuffle chess all in one program. Also added analysis mode in atomic, losers, giveaway/suicide, crazyhouse, 3checks and regular chess.
I have created some bat files to handicap it at the various variants into 5 levels of difficulty. They are:
Just extract them into the winboard folder and you can click on one of them to run pulsar at that variant at that difficulty.
June 14, 2007 pulsar2007-9a-release.zip   This version plays normal chess, 3checks, atomic, crazyhouse, losers, 2kings, suicide/giveaway and shuffle chess all in one program.
Update March 15, 2009 for windows: engine only. pulsar2007-9a-1.zip.  This is an update of the 9a program for those interested in running it on an ics. It fixes two bugs that only impact ics play. One is problems resuming games in atomic and the other is not always using its book.
Note on handicaping: you can handicap pulsar to only search a certain amount of plys in different variants and normal chess. You need to use a program argument. The program arguments are:
mxA-1 through mxA-5 for atomic searching to ply 1 through 5.
mxT-1 through mxT-5 for 3checks searching to ply 1 through 5.
mxC-1 through mxC-5 for crazyhouse searching to ply 1 through 5.
mxS-1 through mxS-5 for suicide ( like icc giveaway exept you cant castle) searching to ply 1 through 5.
mxL-1 through mxL-5 for losers searching to ply 1 through 5.
mxO-1 through mxO-5 for the chess variants ( includes regular chess, shuffle chess and 2kings) searching to ply 1 to through 5.
to enter a program argument type instead of: -fcp pulsar2007-9a.exe         instead type -fcp "pulsar2007-9a.exe mxA-3" for example to handicap it to play atomic to ply 3. If running on the icc you can use multiple handicaps all listed at once ( whats not handicapped will play at full strenght). For example: -fcp "pulsar2007-9a.exe mxA-3 mxO-3 mxT-4 mxC-2"
I havent had a chance to test these much but the compile seemed to go fine. People who have tried it say it works fine. These linux links are just the executable. You can get the books from the Windows download.
Pulsar 2007-9b for Linux comes "as is", without any guarantees, and using it is entirely at your own risk. It can be freely redistributed in unmodified form, alone or in combination with other software.
to make pulsar use variants you need to use the xboard '-variant' argument when you start it. You can use both -variant and /variant in winboard. examples:
Winboard and Xboard can be downloaded at the Winboard Forum
To run pulsar at home put: winboard.exe -fcp "pulsarV2.01e.exe"
Click on it to run.
Pulsar2007 plays variants so if your running a variant in home play you need the -variant or /variant option and the variant name which is listed above in the linux download section. only -variant works in linux though. Example:
winboard.exe -fcp pulsar2007-9a.exe -variant atomic
For pulsar2007-9a, if you want to use program argmenmts, described onpulsarscoop2.html then put the program name with its arguments in quotes. example: winboard.exe -fcp "pulsar2007-9a.exe mxA-3" -variant atomic
To run pulsar on an ics you need some additional flags than just -fcp which stands for first chess program. You will need -zp to tell it to be in zippy mode or automated mode, -ics to tell it to be in internet mode as well as -icshelper and -icshost to tell it to use timestamp or timeseal and to tell it what host to connect to.
Example chessclub.com is a host.
Winboard.exe -zp -ics -icshost chessclub.com -icshelper timestamp.exe -fcp "pulsarV2.01e.exe"
Information on these and other flags can be found in the winboard help index or help contents.
I am just going to write briefly here some historical comments. My first real experience with computer chess was the chess board program fidelity excellence which i purchased for my birthday December 1987 [ see thoughts on chess board computers. ]. I was 17. I played that program at level 1 and could beat it with clever rook mates. But I never could beat it at level 6 or higher.
In 1996 i returned to chess, got a bit better, and could finally beat it at all times under a minute per move. I had done some programming in the meantime. As of yet, I hold no degree in programming, but at the time I had made a arkanoid clone for dos called powerout which I distributed as shareware and a text editor. powerout 2.5 , a vbdos 1 game, and be sure to read the readme.txt for a few useful hints.
In 1997 I bought fritz 4 and in April of 1998 I joined the icc. Shortly thereafter I began to run a crafty account. I was new to internet chess and computer chess seemed like an exciting avenue to pursue. About 2 months after I started my crafty account I decided to write a chess program. This was october 1998.
With help from people on icc's channel 64 most notably kiwipete and diepeveen I got pulsar running on the icc in December and January of 1998/99. It was written in c. The early version did not have a qsearch. It had capture extensions. It only ordered moves by captures and killer moves at the start. Eventually hashing and null move were added and pulsar broke 2200 in the fall of 2000.
In the fall of 2002 I added wild capactiy to pulsar including atomic and 3checks. Atomic has evolved into its own independent program. Now in June 2003 pulsar has been released for the first time.