Tech help needed: Partitioning an external HD

[Barkeep49]

I recently purchased an external HD. I would like to partition it so that one partition works with my windows desktop while the other works with my mac laptop. When I partition in either Windows XP or OSX I can only get it to be recognized with-in that particular OS. Is there a utility I can d/l to help me with this or is there a way to do it with-in the OSes that I am too inept to figure out?

[cartman]

You need to tell it to use less than the whole disk. It sounds like you are telling Windows or OSX to partition the entire drive. For example, if it is a 500GB drive, tell Windows to create a 250GB partition, then once that is done, hook it up to the Mac and tell it to create a 250GB partition using the un-partitioned space.

[Barkeep49]

You need to tell it to use less than the whole disk. It sounds like you are telling Windows or OSX to partition the entire drive. For example, if it is a 500GB drive, tell Windows to create a 250GB partition, then once that is done, hook it up to the Mac and tell it to create a 250GB partition using the un-partitioned space.
I tried that, or at least thought I did, but no dice.