Read Buffer (E4H); Figure 89. Read Buffer Command (E4H) - IBM IC35L020 - Deskstar 20 GB Hard Drive Specifications

15.11 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 89. Read Buffer Command (E4h)

The Read Buffer command transfers a sector of data from the sector buffer of 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 0
IDN 0 ABT T0N AMN
0 0 V 0 0
Deskstar 60 GXP Hard disk drive specification
Command Block Input
Registers
Register
Data
Error
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Status
Status Register
7 6 5 4
BSY RDY DF DSC
0 V 0 –
123
7 6 5 4 3 2 1 0
- - - - - - - -
see below
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
see below
3 2 1 0
DRQ COR IDX ERR
– 0 – V