What are the basics of the ATA interface?
The ATA interface is a very simple interface based on an ISA bus I/O device architecture. The interface consists of two sets of I/O registers, mostly 8-bit, for passing command and status information. The registers are like a set of mail boxes with a door on front and back connected such that both doors can not be open at the same time. The front door is open when the Busy bit in the Status register is zero and the host can read and write the registers. The back door is open when the Busy bit in the Status register is one and the ATA device can read or write the registers. The physical interface contains just enough signals for a 16 bit data bus, five register address bits, and a few control signals like read register, write register and reset. ATA devices look like traditional hard disk drives even though some are not really a hard disc with rotating platters. User data is recorded in 512 byte sectors. Each sector has a sector address. There are two ways to express sector addresses: b
