Panasonic has introduced a write-once Blu-ray disc with a 4x writing speed, faster than any other high-definition disc, available in 25GB and 50GB (dual layer). The consumer electronics company plans to release the former this month and the larger disc in September. The discs have a maximum data transfer speed of 144Mb/s, which means 1GB of data can be written onto the disc in a minute. Panasonic, which is the brand name of Matsushita Electric Industrial, says the new discs have new technology that reduces the error rate to one-tenth of a conventional disc. Fewer errors mean higher reliability and better quality recording.