I/O tracing

[YU,SAMMY]

Hi,
	Please CC me as I'm not subscribed on the list, thanks.  Not sure if
this is appropriate forum, is there an existing tool/module for capturing
all the I/O requests such as:

Unique Identifier
Start Time
End Time
Device Identifier
Operation Type (Read Or Write)
Offset
Length (Number Of Bytes)

I am aware of existing /proc/disks and partitions, but these aren't real
time.  If not, are there any facilities in the kernel I can put a hook in to
keep track of the I/O?

Thanks in advance,
Sammy Yu
Hewlett-Packard