Codes on Garcia-Stichtenoth curves with true distance greater than Feng-Rao distance

We give codes on all members after level 4 of the family of Garcia-Stichtenoth (see Invent. Math., vol.121, p.211-22, 1995) curves with the property d/sub true/>d/sub FR/. These codes also give an improvement on Tsfasman-Vladut-Zink bound.