04h

Read

Write

Write with Verify

Read (No caching)

Write (No caching)

Write with Verify (No caching)

These operations are relatively straightforward, except for the calculation of the location to read.

The disk location to access is calculated as follows:

Absolute Disk Location =

Absolute location of Master/Extended Boot Record + Hidden Sector Field of Logical Drive BPB
+ RBA Offset in Request Packet

The no caching versions of these commands are handled identically to the regular versions except when commands 18h through 1Ah are processed. To suppress adapter level hardware caching, the appropriate bits are set in the EXECUTE_IO IORB.