As the name suggests, RAW files contain the same data captured by the CCD but with no processing by the camera.
RAW files basically hand the raw unprocessed data - at 12 bits per channel - from the camera's imaging chip to your computer. Lossless compression is applied to reduce filesize slightly without compromising any quality.
Not all cameras support RAW and those that do will not append color space info (so you need your cameras ICC profile). Additionally you may have difficulty viewing RAW files in your photo editing programs (if they do not support it) though you should be able to import them using TWAIN
