Embedded Systems Design, 2nd Edition

220 Embedded systems design

With the LUN, the task can create another parameter block,

containing the data, and ask the I/O services to write the data to

the file. This may require the I/O services to make system calls of

its own. It may need to call the file services for more data or to pass

further information on. The data is then supplied to the device

driver which actually executes the instructions to physically write

the data to the disk. It is generally at this level that the logical

nature of the I/O request is translated into the physical character-

istics associated with the hardware. This translation should lie in

the domain of the device driver ...