Read Buffer (E4H); Figure 92. Read Buffer Command (E4H) - IBM IC25N020ATDA04 - Travelstar 20 GB Hard Drive Specifications

13.13 Read Buffer (E4h)

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 0 0

Figure 92. Read Buffer command (E4h)

The Read Buffer command transfers a sector of data from the sector buffer of the device to the host.
The sector is transferred through the Data Register 16 bits at a time.
The sector transferred will be from the same part of the buffer written to by the last Write Buffer command.
The contents of the sector may be different if any reads or writes have occurred since the Write Buffer
command was issued.
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
1 - 1 D - - - -
1 1 1 0 0 1 0 0
4 3 2 1
IDN 0 ABT T0N AMN
0 0 V 0
Travelstar 48GH, 30GN & 15GN 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
0 0 V 0
138
7 6 5 4 3 2 1 0
- - - - - - - -
see below
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
see below
4 3 2 1 0
DSC DRQ COR IDX ERR
- - 0 - V