Cabinet-friendliness
Cabinet-friendliness is an aspect of computer software in which every function is 100% controllable using a MAME-like arcade control interface. In the case of emulators or games, if the controls are able to be redefined to match MAME's, and the software requires no keyboard intervention, then it may be considered cabinet-friendly.
Requirements
MAME Keys
In MAME, the typical default keys for player 1 are: up, down, left, right, CTRL, ALT, SPACE, Left Shift, Z, X, 1, and 5 (coin); the default keys for player 2 are: R, F, D, G, A, S, Q, W, I, K, 2, and 6 (coin). Many keyboard encoders, such as Ultimarc's I-PAC 2 PC interface, are designed to be used directly with MAME, and therefore utilize only these keystrokes.
Mouse / Trackball
Games which are primarily control by a mouse may be considered cabinet-friendly, due to the fact that cabinet builders often install a trackball assembly in the cabinet's control panel.
Examples of Cabinet-Friendly Software
Emulator frontends, such as Wah!Cade, are operated using the same keys as in MAME.
Non-MAME emulators, such as ZSNES and Gens/GS, have redefinable inputs that can match MAME's.
Jukebox programs, such as MultiJuke, are specifically designed media players that are controlled by MAME's keys.
Examples of Cabinet-Unfriendly Software
Massively multiplayer online role-playing games (MMORPG), such as World of Warcraft or Guild Wars, are an inherently social experience requiring full use of a keyboard.
Many flight simulators and 1st person shooters require full use of a keyboard.
Varying Degrees of Friendliness
Some users may feel that a certain amount of keyboard intervention is forgivable as long as it does not disrupt the natural flow of gameplay. For example, if a game requires keyboard input only for the purposes of high-score name entry, this may be perceived as tolerable.
On the other hand, if a cabinet builder does not plan to include a keyboard in his/her finished product, or if the keyboard is inconvenient to access (e.g.: inside a locked door), then anything less than 100% cabinet-friendliness would be unacceptable.