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All three versions come with the systems (Athlon XP 1600+; Intel Cen- Chess Engines and GUIs Shredder Classic GUI and are available trino 1.5 Mhz, both with 512MByte by download from the Shredder website RAM) the GUI reacted very slowly. An The chess engine is the core element of only. The site does not offer boxes with update promised by Stefan Meyer- any chess program; this is where the media and manuals. Kahlen last November removed most of game playing intelligence resides. A Stefan Meyer-Kahlen wrote the engine the original GUI version’s worst bugs, GUI that gives you a graphical represen- in C and compiled it directly for Linux. such as disappearing pieces, but this tation of the board, and visualizes the The engine runs natively, but it is update failed to bring the GUI up to game, is needed to help you control the engine. The most popular engines for slightly slower than its Windows coun- speed. Linux include Crafty, Phalanx, terpart, according to the vendor. This is Missing Features Gnuchess, and older versions of Sjeng due to less than perfect GCC optimiza- and . Linux GUIs include Knights, tions, says the developer. Java was used Many features offered by the Windows Xboard, José Chess, or Scid. for the GUI, probably to support versions version of Shredder are still missing from Two different protocols are available for of Shredder 9 for Mac and Shredder 9 for the Linux version. Although large online integrating an engine with a GUI: the Linux without having to reinvent the endgame databases exist, the Linux ver- WinBoard compatible protocol, and the wheel. sion can’t connect to them. And the Universal Chess Interface UCI – the lat- Linux version also lacks many of the ter is by Shredder developer, Stefan Setting Up Shredder 9 clever analysis options available to the Meyer-Kahlen. Most engines and GUIs After purchasing Shredder 9, a mail mes- Windows version. from the open source scene simply sup- sage with a registration number and link The program’s game database does port the WinBoard compatible protocol. to the Shredder 9 download is sent to not let you search for games by position More recent GUIs, such as José Chess, support both WinBoard and the UCI. you. The download is a 4 MB tarball. and stops at 2000 records, which pre- The Polyglot [5] interface helps you inte- After untarring, you can launch the pro- vents serious use, considering that grate UCI engines with WinBoard com- gram by running the accompanying start hundreds of thousands of games are patible GUIs. script, Shredder9 – assuming you have a quite normal. Although Shredder for working Java installation, version 1.4 or Linux allows you to integrate various newer. UCI engines, the program lacks a mode tion key. The engine window gives you On launching the program, you are where two engines can play each other, an overview of possible moves. prompted to select a language and then in contrast to the Windows version. The Linux version comes without a restart. The program comes up with a The program even lacks a print function manual, but well-organized menus make tidy GUI, which is divided into four pan- for printing completed games including the program functions easily accessible els. These panels are the windows for diagrams. to users, assuming you are familiar with the chess board, a clock, the game sta- This said, Shredder 9 for Linux does the game of chess. Right clicking the no- tus, and the engine area (Figure 1). have a 100MByte collection of openings, tation window takes you to a palette for After a few moves, you might notice which you can download as a 27MByte quick game commentaries. The Mode that the GUI is a bit sticky. On our lab compressed file after buying a registra- window takes you to the possible play- ing modes. The Analysis entry will continue to analyze a game for the best possible move for as long as you let it. Shredder Linux supports multiple variant analysis. If you are eager to learn more about the game, you can enter complete variant paths and play the options against vari- ous engines. You can promote useful variants to main variants, and drop poor variants. If so desired, Shredder will point out possible dangers by showing you a red arrow, or point out promising moves by displaying a green arrow ([Ctrl]+[T]). Game Options If you play at club level, you may be in- terested in a Shredder option that allows you to play chess games with tourna- ment-style rules based on a preset Figure 1: The Shredder interface combines chess board, clock, game protocol, and engine con- schedule. For instance, you can use trols in a single GUI. Shredder to play blitz chess with time

WWW.LINUX - MAGAZINE.COM ISSUE 66 MAY 2006 85 LINUXUSER Shredder 9

Figure 2: Shredder 9 supports several time options and lets you restrict the computer’s strength. penalties, or you can play longer games tions make aggres- with more time checks. Shredder users sive moves with Figure 3: Shredder 9 supports alternative engines, as long as they can even assign themselves a Human the queen. Shred- support the UCI protocol. bonus – this feature is quite a good idea der 9 takes addi- when you consider how long it takes to tional steps to simulate the play of an in- most powerful chess engines in the move chess pieces by dragging the experienced human. world. mouse. The lowest level (1000 ELO) should Shredder 9 is also useful for beginners even give occasional players an opportu- Conclusions and occasional players. The Mode | nity to beat the machine. At this level, Despite the slow GUI, Shredder 9 for Levels menu allows players to limit the Shredder even “overlooks” the common Linux is a powerful chess tool that left strength of your computerized opponent. checkmate fields g7 and h7 after the me with a good impression. It definitely The strength is measured in the normal opening. But I’m fairly confident that gives you more in the line of features unit ELO (Figure 2). Linux Magazine does not have too many than a combination of, say, Xboard/ At the lowest playing levels, the pro- readers who could beat Shredder 9 with- Crafty or Knights/ Crafty, although it can- gram even imitates typical human errors. out any restrictions. not compete with the feature-richness Other chess programs typically devalue of the Scid chess database. On the other their pieces at beginner and fun levels, Functions and Features hand, the Shredder Classic interface is a and additionally, some chess applica- The GUI has all the functions you would lot easier to handle. expect of a chess GUI, including the abil- The most annoying thing about Shre- Table 1: Shredder 9 Linux ity to rotate and scale the board, to re- dder is the fact that Linux chess players view and replay moves, to input games, have to make do with a subset of the Vendor: Stefan Meyer-Kahlen or to store the game in various data- functions the Windows version offers, Features: + Powerful engine bases. although the asking price is the same. + Professional front-end You can modify the table size in File | When I pointed this out to Stefan Meyer- + Good analysis options – no manual Options | Engine options if required. Kahlen, he simply replied that the Linux – slow GUI Simply put, this is the memory space for version has only been on the market for – missing Windows functions storing the calculations performed by a couple of weeks, whereas the Win- Pricing: Shredder Classic Linux the engine. The value should not be dows version was first released over 10 29.95 US$/ Euros more than half of your computer’s total years ago. ■ Shredder 9 Linux physical memory. Permanent Brain spec- 49.95 US$/ Euros ifies whether Shredder will use the CPU INFO Deep Shredder 9 Linux for calculations all the time, or just when 99.95 US$/ Euros [1] Shredder 9: http:// www. it is the program’s move. Source: http:// www.shredderchess. de shredderchess. com/ If you intend to use other programs while waiting for the engine to make a [2] Crafty: http:// www. cis. uab. edu/ hyatt/ TIP move, you can enable the Engine with hyatt. html low priority option. [3] Scid: http:// scid. sourceforge. net The board in Figure 1 shows a well- As previously mentioned, Shredder [4] José Chess: http:// jose-chess. known checkmate problem: black is will work with other engines, as long as sourceforge. net looking to convert his pawn, which has they support the UCI protocol. If you are advanced well up the board, to force [5] Polyglot: http:// theorie. physik. a keen player, you might additionally white to concede. It’s white’s turn. Do uni-wuerzburg. de/ ~arwagner/ chess/ like to try out the commercial Fruit 2.2.1 you see a way out of this tricky situa- shredder. html (29 Euro) [6] engine, which was recently tion? [6] Fruit: http:// www. fruitchess. com released for Linux and is also one of the

86 ISSUE 66 MAY 2006 WWW.LINUX - MAGAZINE.COM