On Dec 26, 0:19, tim lindner wrote:
> In the data sheet, under the section "1. Non-IBM Formats" it says:
>
> "Note that the Index Mark is not required by the 179X."
>
> What does this mean exactly? How can a track contain any useful
> imformation without a Index Mark?
The Index Mark is a single small block of data recorded on the disk,
that occurs once per track, right after the index hole; it's NOT the
index pulse from the hardware, and NOT a sector header and it is
optional. Lots of controllers don't put it there unless told to.
Given that any sensible controller will see the index pulse from the
drive interface, the Index Mark pattern is unneccessary -- but some
controllers do expect to see it.
--
Pete Peter Turnbull
Network Manager
University of York
Received on Fri Dec 26 2003 - 09:22:22 GMT