good sharing. following up on your comments: in the kernel source: block/*.c are the files for block I/O related stuff - the layer just before ATA, implementing stuff like elevator I/O etc. drivers/block/*.c: hardware-specific files that understand how to talk to each type of harddisk. drivers/scsi/*.c: generally SCSI protocol related stuff (lib*.c), but may contain device specific stuff. drivers/ide/*.c: drivers/ata/*.c: among the lowest level just before sending out port I/O operation. On Fri, Feb 8, 2013 at 8:26 AM, <Valdis.Kletnieks@vt.edu> wrote:
On Fri, 08 Feb 2013 07:48:39 +0800, Peter Teoh said:
So the drivers just literally concatenate these command into a string and send it over to the device.
The reason that good disk drivers are hard to write is because it isn't *just* literally concatenating the commands - it also has to do memory management (make sure that everybody's data ends up in the right buffers), command queue management, elevator management (if there's multiple I/O requests pending from userspace, what order do we issue them in?), error recovery, power management, and a ton of other stuff...
-- Regards, Peter Teoh