ATA PIO Mode: Difference between revisions

Currently there are three addressing modes to select particular sectors to read or write on a disk. They are 28 bit LBA, 48 bit LBA, and CHS. CHS mode is obsolete, but is discussed quickly below. The number of bits in the LBA modes refer to the number of significant bits in the sector "address", called an LBA. In 28 bit mode, LBAs from 0 to 0x0FFFFFFF are legal. This gives a total of 256M sectors, or 128GB of addressible space. So 28 bit LBA mode is also obsolete for many current drives. However, 28 bit PIO mode is faster than 48 bit addressing, so it may be a better choice for drives or partitions that do not violate the maximum LBA value limitation.