Seagate STT8000A manual Atapi Identify Device A1h

Chapter 5 ATAPI Interface

Issuing PIO and DMA transfer modes does not actually select these operations; however, issuing these modes selects the rate of either type of transfer, as selected by the DMA bit (bit 0) of the ATAPI Features register.

ATAPI Identify Device (A1h)

The protocol and timing of this command conforms to a standard ATA type command as defined in ATA-2.

Note: This command is similar to the ATA Identify Device command except it uses a different op-code. The ATA Identify Device command is aborted.

This command is generally intended to be used by a low-level ATAPI driver to determine the number and type of ATA/ATAPI devices attached to the interface. This driver might be able to program transfer rates and other parameters in the host ATA (IDE) interface.

The following table defines the values returned by the drive.

Word	Description	Value	Meaning
0	General Configuration	81C0h	ATAPI Streaming Tape, Removable
			Accelerated DRQ, 12 byte packets
1-3	Disk info: cylinders, heads	0000h	Unsupported
4-6	Disk info: track, sector sizes	0000h	Unsupported
7-9	Reserved	0000h	—
10-19	Serial Number (20 ASCII characters)	"N...N"	Serial Number
20	Buffer Type	4002h	Cap & Mech Sts bytes 6 and 7
21	Buffer Size	02D8h	14 frames of 52 data blocks=728
22	ECC Bytes Available	0000h	Unsupported
23-26	Firmware Revision (8 ASCII	"N.NN"	Firmware Revision
	characters)
27-46	Model Number (40 ASCII characters)		Model Number. "Seagate STT8000A"
47,48	Disk info: mult-xfer, double word I/O	0000h	Unsupported
49	Capabilities	0F00h	IORDY supported. Logical Blocks
			Addressing and DMA supported
50	Reserved	0000h	—
51	PIO Data Transfer Cycle Timing	0200h	Mode 2
52	DMA Data Transfer Cycle Timing	0200h	Mode 2

Page 36 STT8000A Product Manual