The M4 corridor is an area in the United Kingdom adjacent to the M4 motorway, which runs from London to South Wales. It is a major hi-tech hub. Important cities and towns linked by the M4 include London, Slough, Bracknell, Maidenhead, Reading, Newbury, Swindon, Chippenham, Bath, Bristol, Caldicot, Magor, Newport, Cardiff, Llanharan, Port Talbot, Swansea and Llanelli. The area is also served by the Great Western Main Line, the South Wales Main Line, and London Heathrow Airport. Technology companies with major operations in the area include Adobe, Amazon, Citrix Systems, Dell, Dragon International Studios, Huawei, Lexmark, LG, Microsoft, Novell, Nvidia, O2, Oracle, Panasonic, SAP, Siemens Mobility and Symantec.