Thanks, That was it, it was still mounted. Also questions with how Apple's Disk utility Formats it as MS-DOS, does it format as FAT 16 or FAT32 cause when I read the Boot info, it says FAT16 as the FS type and BSD 4.4 as the BS_OEMName. Also where would I find the bootsector structure for the MS-DOS FS that Apple's Disk Utility makes when you format the Drive as MS-DOS. thanks, Matt On May 23, 2004, at 1:41 PM, Justin Walker wrote: On May 23, 2004, at 11:48, Matt Jaffa wrote: Hi, I am wanting to be able to have access to my external HD by opening it up using something like open(......); and reading the bootsector and switching Sectors around and stuff. My questions might be screwy, but I don't know how to go about doing this, I don't know if I have to write a kernel Extension or if I can do this in User space. Basically I want to mess around with an External HD that is formatted totally in MS-DOS. So what do I need to do to get access to the drive. When I do open(.....) in user space, it says the drive is busy. That is usually an indication that the drive/partition is mounted as a file system. Check with the 'mount' command to see whether this is the case. You should be able to access the "raw" partition if it's unmounted (and file permissions for /dev/whatever are correct). You might want to look at some file system and 'boot' code to see how to interpret the partition data. And yes, you can read and write disk partitions in user mode. Regards, Justin -- Justin C. Walker, Curmudgeon-At-Large * Institute for General Semantics | It's not whether you win or lose... | It's whether *I* win or lose. *-------------------------------------- *-------------------------------* _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.