02-06-2016, 02:35 PM
You can place the write splice where ever you like. You don't have to use the index as a reference... however, I do both... by writing more than 1 rev (starting at the index) and terminate the write in an exact location. This is how SPLICE mode works.
You can write a track starting at any random location by not using the index flag when doing the write. Using the index as a starting point and writing more than 1 revolution gives you the ability to put the write splice anywhere you like in reference to the index pulse. For example, you can could put the write splice exactly 180 degrees from the index pulse by calculating the number of bitcells that would need to be written over the course of time of 1 1/2 rotations of the disk. If the drive is spinning at 300 RPMs, that's 200ms per revolution, so 180 degrees would be 100ms. Now, you just need to add up the bitcell times to equal 200ms (1 rev)+100ms, and you know exactly how much data needs to be written. You can of course be exact and factor in the exact length of the track vs. the drive speed. You can make it +/-1 bitcell if you have a stable drive speed.
You can write a track starting at any random location by not using the index flag when doing the write. Using the index as a starting point and writing more than 1 revolution gives you the ability to put the write splice anywhere you like in reference to the index pulse. For example, you can could put the write splice exactly 180 degrees from the index pulse by calculating the number of bitcells that would need to be written over the course of time of 1 1/2 rotations of the disk. If the drive is spinning at 300 RPMs, that's 200ms per revolution, so 180 degrees would be 100ms. Now, you just need to add up the bitcell times to equal 200ms (1 rev)+100ms, and you know exactly how much data needs to be written. You can of course be exact and factor in the exact length of the track vs. the drive speed. You can make it +/-1 bitcell if you have a stable drive speed.