
This is new with OS X, as documented in "Mac OS X: Apple Double Format Creates File Name With the Prefix '._'." The resource fork contains metadata about the file that is exclusive to the Mac. This is called Apple Double Format and is normal. When you copy or save a file from a Mac to a Windows shared volume or Windows-formatted disk, the Mac creates two files:.Disk Utility only permits you to format the entire drive in MS DOS format: it does not permit you to partition the drive so that some partitions are in MS DOS format while others are in Mac OS Extended (aka HFS Plus or HFS+) format.While it is possible to format the external drive in MS DOS (FAT32) format for use with both Macs and PCs, this has a number of side effects that are best avoided. MacDrive for Windows permits Windows computers to use disks in Mac formats. Install Mediafour MacDrive for Windows on the PC.Prior to reformatting the external drive, backup any data on it that you wish to save. Format the external drive in Mac OS Extended format: see the Disk Utility Help documents concerning partitioning a disk.

If you have an external drive that you want to share between two locations, such as home and office, and have a PC at one location and a Mac at the other, then the best way to physically share the drive is: a FireWire® or USB 2.0 drive, between a Mac running Mac OS X 10.5 Leopard® and a PC running Microsoft® Windows®: physically or over a local network. There are two ways to share an external drive, i.e.

Sharing an external drive between a Mac and a PC under Leopard
