Read Buffer (E4H); Figure 97. Read Buffer Command (E4H) - IBM DTLA-305040 - Deskstar 41.1 GB Hard Drive Specifications

12.11 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 97. 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 com-
mand. 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 40GV & 75GXP hard disk drive specifications
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 –
127
7 6 5 4 3 2 1 0
- - - - - - - -
see below
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
see below
3 2 1 0
DRQ COR IDX ERR
– 0 – V