Go to Arcane Magics      Go to Epic MysteriesGo to Game Mechanics     Go to Greyhawk Locations
Maldin's Greyhawk

2nd Edition Combat Computer

by Denis Tetreault
 Version 1.5

Over all of the various editions of Dungeons and Dragons, DM's have used a variety of techniques and tools during their gaming sessions. One of the first (and most useful) tools was the 1st Edition DM screen, which had quick-reference tables including ones for combat, saving throws, weapon damage, and quite a few others. There was also a 2nd Edition screen, however the introduction of THAC0 was an attempt to do away with tables. Some DM's liked THAC0, others did not. Even the use of the iconic DM screen varies from game to game, depending on your DM style. Depending on your house rules, much of the real estate on the various available DM screens is wasted space, filled with tables that you may never use. Many DMs choose not to use a screen at their gaming table.

I do use a DM screen (actually, the one I use is the original 1st Edition screen... how 'bout that for nostalgia!), but it mainly functions only as a barrier to prevent the players from seeing my notes and maps. I rarely use the tables on the screen. Instead, what I use is a modified "Combat Computer" from Dragon Magazine #74, an adjustable disk used for calculating "to hit". Basically, you spin the top disk until the arrow points to the target's armor class, then you can easily read what all PC classes (and creatures) of all levels need to hit that particular AC. Dial in the "monster", and you can look up numbers for the entire party without moving the disk.

Covering the free space on the back and front of the disk are small-font charts, lists, and other information that I found over the years to commonly need during play. And the disk is never buried under material. I just balance it on the edge of the DM screen, and it's literally at my fingertips at all times.

The original Combat Computer was 1st Edition, but I modified it for 2nd Edition AD&D (which I still play), and it could theoretically be modified yet again by other DMs for any edition (or RPG variant). One of the things I didn't particularly like on the original charts was the fact that attack and saving throw progression didn't change for several levels, then would jump 2 (or more) units. On this disk, I smoothed out the level progression for both. Among the other charts that you will see on the front and back of the disks are Strength and Dexterity adjustment tables, Armor Class tables, various situational combat modifiers, clerical undead turning, currency conversion, saving throw tables, intelligence vs. illusion saves, two-handed combat tables, my own critical hit table (also available on my website), non-proficiency penalties, a chart I use for lock difficulty, poison-related charts, cover vs. missile fire, thief backstabbing, a Greyhawk calender conversion, and a few other things. Pretty much 95% of what I commonly need while DMing. It saves a heck of a lot of looking up stuff during play (seeing as the screens are often covered with stuff I don't actually use).

The images below should be printed out and glued to some sort of backing board. For the back disk, I used thin corrugated cardboard, so that it is stiff, and glued the center disk to one side, and the back side (with the saving throw and critical hit charts) to, well, the back side. The front disk is glued to a stiff non-corrugated piece of cardboard (so that its not too thick). You'll need some sort of rivet or connector to hold them together that allows the disks to freely spin. My disk is held together by the snap from a hospital-admitting wrist band.

You'll notice a small window cut into the top disk. In my campaign I also have make use of a specialized wizard sub-class of enchanter based on the Houri class from an old issue of White Dwarf Magazine, and that window is a seduction chart (AC arrow points to the difference between the Houri's and victim's level, read the percentage chance of success in the window). I am certain DM's can find other uses for that percentage. There is certainly space on both the front and back sides to add more charts that you might find useful in your own campaign. One could even add more windows like the seduction calculator.

For a smaller file (300 dpi, average of 500k each), right click the images below and select "Save Image". For higher resolution images (600 dpi, average of 1MB), left click on the images below. For some reason, when I view the hi-resolution images in an older version of Netscape, they do not appear, however if you right click on the blank browser window and save the file, you'll be able to do so normally. Other browsers don't seem to have a problem. When I figure out why this is happening, I'll fix the page. Eventually, I'll redo all the text on the disks within Photoshop and remove the scanned image (look for page version 2.0 some time in the not-so-immediate future). It will all be much clearer then.

front disk of combat computer

center of combat computer

back side of combat computer

site map

   Visit my active site map to see the entire website at-a-glance, find out whats new, and instantly jump there with just a click.

Return to the Game Mechanics Page
Return to my main Greyhawk Page (in case you got here through a search engine)
This page last modified on September 26, 2008