LBA logical block addressing Until LBA, PCs with IDE controllers were limited to accessing hard disks of 528MB or less. Why? Because IDE's addressing model didn't allow addresses large enough to work with bigger drives. (It wasn't really IDE's fault. IBM's original design for disk access on the old IBM AT started the problem.) LBA, a feature of the Enhanced IDE (EIDE) drive standard, lets the drive controller perform an address conversion, bypassing the bottleneck and allowing for drives up to 8.4GB. See also: IDE