Drum tablature, commonly known as a drum tab, is a form of simplified percussion notation, or tablature for percussion instrument. Instead of the durational notes normally seen on a piece of sheet music, drum tab uses proportional horizontal placement to indicate rhythm and vertical placement on a series of lines to represent which drum from the drum kit to stroke. Drum tabs frequenctly depict Drum patterns.
Key or Legend 
The number of lines in a specific tab will vary depending on the number of different drums used during a specific section of music. Below is an example of a basic drum kit.
CC|-Crash cymbal----| HH|-Hi-hat----------| Rd|-Ride cymbal-----| SN|-Snare-drum------| T1|-High-tom--------| T2|-Low-tom---------| FT|-Floor-tom-------| B |-Bass-drum-------| Hf|-Hi-hat-w/foot---|
Tablature can use various letter and symbols to denote different cymbal types or other drum techniques. These are the tablature symbols that represent various techniques, though these may vary:
|-x-| Strike cymbal or hi-hat |-X-| Strike loose hi-hat, or hit crash hard |-o-| Open hi-hat |-#-| Choke cymbal (grab cymbal with hand after striking it) |-s-| Splash cymbal |-c-| China cymbal |-b-| Bell of ride |-x-| Click hi-hat with foot
|-o-| Strike |-O-| Accent |-g-| Ghost note |-f-| Flam |-d-| Drag |-b-| Soft one-handed roll |-B-| Accented one-handed roll |-@-| Snare rim
Example Drum Tab 
Below is an example of a rhythm pattern characteristic of much popular music including rock presented in standard notation and then its corresponding translation into drum tab.
HH|x-x-x-x-x-x-x-x-|| S|----o-------o---|| B|o-------o-------|| 1 + 2 + 3 + 4 +