Read Sectors (20H/21H); Figure 90. Read Sectors Command (20H/21H) - IBM DJSA-210 - Travelstar 10 GB Hard Drive Specifications

13.17 Read Sectors (20h/21h)

Command Block Output
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 90. Read Sectors command (20h/21h)

The Read Sectors 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. If an uncorrectable error occurs
the read will be terminated at the failing sector.
Output Parameters To The Device
Sector Count
Sector Number
Cylinder High/Low
H
R
Registers
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
0 0 1 0 0 0 0 R
4 3 2 1
IDN 0 ABT T0N
V 0 V 0
The number of continuous sectors to be transferred. If zero is specified, then
256 sectors will be transferred.
This is the sector number of the first sector to be transferred. (L = 0)
In LBA mode this register contains the LBA bits 0–7. (L = 1)
This is the cylinder number of the first sector to be transferred. (L = 0)
In LBA mode this register contains the LBA bits 8–15 (Low) and bits
16–23 (High). (L = 1)
This is the head number of the first sector to be transferred. (L = 0)
In LBA mode this register contains the LBA bits 24–27. (L = 1)
This is the retry bit. If is set to one and then retries are disabled.
Travelstar 32GH/30GT/20GN 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
AMN BSY RDY DF
V 0 V 0
136
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