External HDD in OS 9

Hi, hockeyboy. You'll have to use FAT32 format, the only one that OS 9 and Windoze can both read. NTFS is out, as are the Mac OS Standard and Mac OS Extended formats.

FAT32 format has no place in it for whatever is stored in the resource fork of a Mac file, so make sure the only files you move from the Mac to the Windoze box are in cross-platform formats (which don't use the resource fork at all). Files that have resource forks on the Mac side will lose them when you write them to a FAT32 disk, and many such files are effectively destroyed. If it's true that you only want to move data one way — from the Windoze box to the Mac — this will be a non-issue for you.

If, when you're done moving the data from the PC to your Mac, you want to keep using the drive with the Mac, you should reformat it as Mac OS Extended.

When you format a disk in a Mac using Drive Setup, choosing the MS-DOS option results in a FAT32 format, so the initial formatting of your drive can be done either on the PC or the Mac. It is not possible to write separate Mac- and PC-formatted partitions to a single disk in OS 9.