On 2015-12-01 19:04, Johnny Billquist wrote:
On 2015-12-01 18:09, Paul Koning wrote:
I suppose it's possible to do something like interleaving where
consecutive sector addresses are not physically adjacent on the
media. Come to think of it, that's exactly what the MSCP RX50
controllers do, since MSCP implements the mapping from LBA to physical
addresses in the controller, not the host. But in older systems where
the controllers handle physical addresses and the mapping from LBA is
in the driver, interleave is handled there (or above).
Yes, the "hardware" interleave is what I was assuming everyone here was
talking about. Otherwise there is no point/need to format to get the
interleaving... With disks, this is perfectly doable, as the block
number is in the block header, and the drive/controller scans headers
until the current block passes by. There is no real reason to actually
place the disk blocks in consecutive physical order on the disk. Any
order will work. That's what soft sectors gets you.
To point it out more clearly, in case this seems muddled. The hardware
interlaving done by MSCP for the RX50 do not really have anything to do
with MSCP and the ability to map blocks around.
When the floppies are formatted, the sector numbers are written in the
header of each sector. All later operations always search for the
correct sector by checking the sector header. As such, this not only
works on MSCP controllers, but any floppy, on any floppy controller.
And in theory also on pretty much any other kind of disk as well. The
trick is the ability to format the disk and write the header. For most
disks you cannot do that yourself.