On Fri, 2005-10-21 at 17:02 -0400, Dale Blount wrote: > I'll agree with that as well, but there should be a note left on > CONFIG_LBD's help menu that states 1TB (or whatever the actual limit is) > instead of 2TB then. No one's really bothered to find out, I suspect. If the kernel is using block offsets as all unsigned (which I'm not sure anyone's fully validated), and the block size is 512, then 2TB is the limit. For signed, which is a safer assumption, it's 1TB. However, you also have the constant source of overflow danger, like you just discovered. Every arithmetical calculation has to divide first then multiply (because the reverse will overflow). Note also that fdisk overflows beyond a certain point (which I suspect is also 1TB). > Also are there any performance implications for using CONFIG_LBD? Yes, on 32 bits sector_t becomes unsigned long long (a 64 bit quantity). This takes double the storage (or registers). I don't think it will affect storage performance any, but it increases the sizes in the kernel and makes the processor do a bit more work. James - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
