Using DD to write to a specific LBA (converting LBA to offset, blocksize, count)

[Mark Perino]

How does one convert from LBA to skip, blocksize, and count?

IE I want to write zero's over LBA 00FF68 through 00FF6F on a raw device
/dev/sda /dev/rhdisk4, /drv/C0T0D0S1, etc..

As an example under AIX I would like to use:

dd if=/dev/zero of=/dev/rhdisk4 skip=AAAA blocksize=BBBB count=CCCC

Where can I obtain the info to calculate AAAA, BBBB and CCCC?  Whatever
platform you can show me how to do the math on I can probably figure out
how to do this on AIX, Linux, Solaris, etc..