Specifications

Identify Drive Command

Word Bit Description

48 — 0000

= cannot perform double-word I/O;

0001

= can perform double-word I/O

(Included for backwards-compatible use)

49 15–10 0 = ATA reserved (should be zero)

49 9 1 = LBA supported

49 8 1 = DMA supported

49 7–0 Seagate reserved

50 ATA reserved (should be zero)

51 15–8 PIO data transfer cycle timing mode

(The PIO transfer timing for each ATA device

falls into categories which have unique

parametric timing specifications. To determine

the proper device timing category, compare the

cycle time specified in Section 6 with the

contents of this field. The value returned in bits

15 through 8 should fall into one of the

categories specified in Section 6, and if it does

not, then mode 0 is used as the default timing.)

51 7–0 Seagate reserved

52 15–8 DMA data transfer cycle timing mode

(The DMA transfer timing for each ATA device

falls into categories which have unique

parametric timing specifications. To determine

the proper device timing category, compare the

cycle time specified in Section 6 with the

contents of this field. The value returned in bits

15 through 8 should fall into one of the

categories specified in Section 6. If it does not,

then mode 0 is used as the default timing. The

contents of this word are ignored if words 62 or

63 are supported).

52 7–0 Seagate reserved

53 15–1 ATA reserved (should be zero)

continued

ATA Interface Reference Manual, Rev. C 43