Read Multiple (C4H); Figure 100. Read Multiple Command (C4H) - IBM IC25N040ATCS04 - Travelstar 40 GB Hard Drive Specifications

13.15 Read Multiple (C4h)

Command Block Output Registers
Register
Data
Feature
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Command
Error Register
7 6 5
CRC UNC 0
0 V 0

Figure 100. Read Multiple command (C4h)

The Read Multiple command reads one or more sectors of data from disk media and then transfers the
data from the device to the host.
The sectors are transferred through the Data Register 16 bits at a time. The command execution is
identical to the Read Sectors command with one exception: an interrupt is generated for each block—as
defined by the Set Multiple command—instead of for each sector.
Output parameters to the device
Sector Count
Sector Number
Cylinder High/Low
H
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
1 L 1 D H H H H
1 1 0 0 0 1 0 0
4 3 2 1
IDN 0 ABT T0N AMN
V 0 V 0
This indicates the number of continuous sectors to be transferred. If zero is
specified, 256 sectors will be transferred.
This indicates the sector number of the first sector to be transferred. (L = 0) In
LBA mode, this register contains LBA bits 0–7. (L = 1)
This indicates the cylinder number of the first sector to be transferred. (L = 0) In
LBA mode this register contains LBA bits 8–15 (Low) and bits 16–23 (High).
(L = 1)
This indicates the head number of the first sector to be transferred. (L = 0) In LBA
mode this register contains LBA bits 24–27. (L = 1)
Travelstar 60GH & 40GN hard disk drive specifications
Command Block Input Registers
Register
Data
Error
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Status
Status Register
0 7 6 5
BSY RDY DF
V 0 V 0
139
7 6 5 4 3 2 1 0
- - - - - - - -
see below
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
- - - - H H H H
see below
4 3 2 1 0
DSC DRQ COR IDX ERR
V - 0 - V