Unlike simple ROMs (which are just dumps of cartridge or EPROM data), CHD (Compressed Hunks of Data) is a lossless compression format developed by the MAME (Multiple Arcade Machine Emulator) team. CHD files are used specifically for:
Tom and Jerry (1992) ran on Midway’s Y-Unit hardware. While the core program (the .bin or .rom files) is small, the game contains large amounts of graphic data, pre-rendered sprites, and sampled audio (like the iconic orchestral swipes and yowls). The .chd file you see contains that bulk asset data, while the parent ROM zip file contains the main CPU instructions. Tom and Jerry in House Trap -USA-.chd
Unlike a simple ROM, CHD files must live in a folder that matches the parent ROM name, not inside the ZIP file. Unlike simple ROMs (which are just dumps of
Correct structure:
mame/roms/
├── tomjerry.zip (The parent ROM)
└── tomjerry/
└── tomjerry.chd (The CHD file, sometimes renamed to match the game)
Note: Some dumps label the file directly as "Tom and Jerry in House Trap -USA-.chd". You may need to rename it to tomjerry.chd for MAME to recognize it. Tom and Jerry (1992) ran on Midway’s Y-Unit hardware
If you are browsing ROMsets, you might see multiple versions. Why specifically hunt down the -USA- tagged CHD?