by Steve Lopez

This week's topic was alluded to in a previous issue of ETN (March 24, 2002, under the heading "Upgrading Shredder6 Using the Fritz7 Service Pack"), but judging from what I've seen and heard via e-mail, phone, and various Interrant computer chess message boards some confusion still remains. So let's dive in and hopefully dispel the confusion once and for all.

First, let's look at some terminology we'll need to know:

In short, the engine is the part of the program that actually plays chess, while the GUI is the display on your screen -- the interface that lets you interact with the chess engine itself.

Way back in the Dark Ages of computers (pre-1997, give or take), the chess engine was basically "welded" into the GUI. You bought Chess Monster 5000 and it came with its own interface. You bought Killer Chess 2.0 and it, too, came with its own interface. But if you really, really loved the screen display and menus of Killer Chess and wanted to somehow run Chess Monster's engine in it (because you really liked the way Chess Monster played), you had no way to do this; the two programs were completely separate and there was no way to run the Monster's engine inside the Killer's GUI. You were basically stuck with the combination of an engine and its interface -- there was no way to divorce one from the other; in essence, the two were the same thing. To use an analogy (admittedly a bad one), it was like having to buy a new VCR every time you wanted to see a different movie, as though the movie itself was a permanent part of the machine and couldn't be extracted.

There was a big downside to this "welding" of the chess engine and interface: if you wanted to play a different chess engine, you had to learn a whole new way of doing things in a different GUI -- the menus were all different, the displays were all different, sometimes even the means of moving the pieces was different.

When Fritz5 was released in 1997, it gave you the option of using modular engines. You could run different chess engines written by different programmers in a single GUI, without having to learn a whole lot of new procedural stuff -- the menus and other features remained the same (because you ran the engines in the same GUI -- you just used a menu command to "unplug" one engine and load a different one, without having to exit the program and fire up a different interface). And you needed just one GUI on your hard drive. If you already had, say, Fritz5.32 installed and you later installed Hiarcs7.32, you could uninstall the Hiarcs GUI (while leaving the engine on your hard drive) -- the Hiarcs GUI was exactly the same as the Fritz GUI, so having it on your hard drive was completely redundant because you could easily run the Hiarcs engine inside of the Fritz GUI.

Back in those days, there were only a relative handful of engines available to be run in the Fritz GUI. Now there are well over a hundred, counting the programs sold by ChessBase plus the "freebies" that are available on the ChessBase GmbH web site.

However, there's now a new twist. As of this writing, three of our programs (Fritz7, Hiarcs8, and Shredder6) all use the new Fritz7 GUI. But if you have more than one Fritz7 GUI on your hard drive, the GUIs are linked so that they will display just one program name when you start the program and on the blue title bar (at the top of the screen) when the program is running.

Here's an example. Let's say that you've already installed Fritz7. You later purchase and install Shredder6. When you double-click on your desktop icon for Shredder6 to start it, the initial splash panel shows "Play Shredder". But when you double-click on the icon to start Fritz7, the splash panel still reads "Play Shredder".

This has caused some major confusion among a small minority of users: "It says 'Play Shredder'! How do I know that I'm really playing against Fritz?"

It's simple -- when you get to the main chessboard screen of the GUI, just hit F3 to bring up a display of all available engines. The engine currently highlighted is the engine that's currently loaded. If you want to switch to a different engine, just click on it to highlight it, set your hash table size, etc., and then click "OK". Also, when an engine is running the name of that engine is displayed in the Engine Analysis pane.

Thus the "Play _______" displayed in the splash panel and the engine name displayed on the blue title bar at the top of the screen are purely cosmetic -- they have absolutely no bearing on which engine is loaded and you're currently playing/analyzing with. In other words, don't fret -- these aren't the "old days" of "welded" engines and GUIs. Just think of changing a chess engine the same way you think of changing a tape in your VCR (or changing a Nintendo cartridge, etc.). The GUI is the VCR or game hardware, while the engine is the movie or game cartridge.

If you want to change the name of the program displayed in the splash panel and blue bar, go to the Tools menu, select "Options", and click on the "Version" tab. You'll see a pulldown menu under "GUI Version"; just select the name of the program you want to be displayed in those two locations. Then click "OK". This will be the program name displayed in all copies of the GUI (regardless of whether it's Fritz or one of the other two programs) on your hard drive (until you change it again) but has absolutely no other bearing on any functions of your program.

For more information on modular engines and related topics, see the following issues of Electronic T-Notes for details:

Removing extra (redundant) interfaces: May 21, 2000 (the big trick to know is that you must rename your \Engines folder)

Upgrading the Shredder6 (and now Hiarcs8) GUI using the Fritz7 service pack: March 24, 2002

Free engines for use in the Fritz7 GUI: December 23, 2001(the issue contains a link to a page at which the free engines are available)

Adapting free UCI engines for use in the Fritz7 GUI: May 26, 2002

The engine selection [F3] dialogue: November 12, 2000 (although the article discusses the display in ChessBase8, it works in the same way as the one in the Fritz7 GUI)

Until next week, have fun!

You can e-mail me with your comments, suggestions, and analysis for Electronic T-Notes.