OnStream has started selling a version of its Echo tape backup drive exclusively for Macs. The Longmont, Calif.-based storage maker first marketed Echo for PCs but recently has turned its attention to the Mac market. The back-up drive uses IEEE 1394, or FireWire, to connect to Apple systems at up to 400 megabits per second. The storage media holds up 30 GB of compressed data. The Echo drive sells for around $500 and supports all FireWire-equipped Apple systems, including Power Mac G3 and G4, Cube, iMac, iBook and PowerBook.