[Coco] Largest Compact Flash in SuperIDE?

Mark Marlette mmarlette at frontiernet.net
Tue May 12 21:23:23 EDT 2020


HDB-DOS and SuperDriver use three bytes for the LSN offset, IE: 24bits.

This is true for SCSI, IDE and SD cards.

Mark Marlette
mark at cloud9tech.com
mark at gamecamaddict.com 

    On Tuesday, May 12, 2020, 06:54:25 PM CDT, John E. Malmberg <wb8tyw at qsl.net> wrote:  
 On 5/12/2020 8:33 AM, Mark Marlette wrote:
> John,
> 24bit LSN are used. Largest OS-9 partition is a bit over 4GB IIRC.
> Superdriver uses 512 byte sectors.
> Chris Hawks CDF reads the ISO9660 format, pretty cool!!!

Ok, the IDE Wiki says the LSN mode stops at 26 bits, so is 24 bits all 
that some registers can handle?

I think that going beyond the 26 bit limits also may also require 
putting the drive in UDMA mode for the transfers.

Lots of good information,


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