The floppy disk drives on these models were in the unusual 3-inch "compact floppy" format, which was selected as it had a simpler electrical interface than 3½-inch drives. In the range's early days supplies of 3-inch floppies occasionally ran out, but by 1988 the PCW's popularity encouraged suppliers to compete for this market. There are several techniques for transferring data from a PCW to an IBM-compatible PC, some of which also can transfer in the opposite direction, and service companies that will do the job for a fee.