MAME uses two different file types for storing ROMs depending on the original medium:
- The majority of ROM dumps are stored in raw format and contained in ZIP archives, one for each game.
- For arcade machines which use hard disks or CDs, MAME uses CHD (Compressed Hunks of Data) files which contain the entire contents of the original hard disk, CD or Laserdisc. Due to the large size of these media, the CHD files derived from them also tend to be large.
Please visit this post for full MAME 0.134 CHD set. All files has been updated and uploaded to Megaupload.