Specifications

Identify Drive Command
Word Bit Description
0 11 1 = rotational speed tolerance is > 0.5%
0 10 1 = disc transfer rate > 10 Mbit/sec
0 9
1 = disc transfer rate ≤ 10 Mbit/sec but > 5 Mbit/sec
0 8
1 = disc transfer rate ≤ 5 Mbit/sec
0 7 1 = removable cartridge drive
0 6 1 = fixed drive
0 5 1 = spindle motor control option implemented
0 4 1 = head switch time > 15 usec
0 3 1 = not MFM encoded
0 2 1 = soft sectored
0 1 1 = hard sectored
0 0 0 = ATA reserved (should be zero)
1 — Number of cylinders
(the number of user-addressable cylinders in
the default translation mode)
2 — ATA reserved (should be zero)
3 — Number of heads
(the number of user-addressable heads in the
default translation mode)
4 — Number of unformatted bytes per track
5 — Number of unformatted bytes per sector
6 — Number of sectors per track
(the number of user-addressable sectors per
track in the default translation mode)
7–9 — ATA reserved (should be zero)
10–19 — Serial number*
(20 ASCII characters, right justified and padded
with spaces [20
H
])
continued
ATA Interface Reference Manual, Rev. C 41