One volume, or one partition? They're different things.
Just open Drive Setup, select the volume you want to erase (can't erase partitions like that), and initialise it.
I'm not sure what you mean though, so... thats how to initialise a volume.
To initialise a partition, highlight it in Finder, and go to the Special menu -> Erase Disk.
I dunno what bearing it will have on everything being an ext2 FS, but... oh well.
Any reply is better than none I guess

HTH
EDIT: Yeah, do what Oscar said - cause I've got no idea where the MacOS comes into any of your plans
Cipher13
[This message has been edited by Cipher13 (edited 02-13-2001).]