[Coco] Largest Compact Flash in SuperIDE?

coco at jechar.ca coco at jechar.ca
Tue May 12 11:59:42 EDT 2020

The partitions you specify in OS9 are based on 256 byte sectors
limiting the partition size to 4GB but are automatically reinterpreted
by the hardware driver to make full use of the 512 byte sectors.
The RSDOS partitions on the other hand waste every second 256 bytes
as HDBDOS does not reinterpret the 512 byte sectors but just uses them 
256 byte sectors.

Where It gets interesting is that the offset values in dmode (wpc and 
for the i0 and i1 descriptors are actually in 512 byte units so one can 
an offset of up to  8GB, also the i0 driver can be cloned and given 
offsets so you could have /dd ( a 128M boot drive. ) /01 ( a 4G os9 
drive. offset by 256M )
  /02 ( a 4G os9 drive. offset by 4 1/4 G ) and /03 ( a 3 3/4 G os9 
drive. offset by 8 G )
for a total of 11 7/8 G under Nitros9 3.2 or 3.3 for a total of 11 and 
seven eights Gig.

Also if you have Nitros9 v 3.3 (2018 or later ) the i1 drive can be 
accessed and one
could create drives /10, /11 and /12 each 4GB giving a total of almost 
24 Gig of accessible
local storage plus Drivewire storage suffice to say more storage then 
you are ever likely
to use for a coco.

As for size of CF card up to 32G should be possible but only the bottom 
12 G can actually
be used for the coco.

Also note that a boot track has not to my knowledge been created to boot 
SuperIDE into
Nitros9 3.3 but if you have a drivewire server running you can create a 
boot to IDE
that works fine but requires a running drive wire server and you get the 
benifit of being
able to access the second drive on your SuperIDE.

Myself I setup RS-DOS drive 63 to boot to Nitros 3.2 and 163  boot to 
Nitros 3.3
and run LINK.BAS to set witch OS to boot. This on CF card I use for 6309 
RS-DOS drive 68 to boot to Nitros 3.2 and 168  boot to Nitros 3.3 on CF 
I use for 6809.

In my system I have the SuperIDE booting from CF and a 16G IDE-SSD 
cartridge that
was formerly my WindowsXT boot drive attached to the 40 Pin IDE 

This is a picture of my usual Super IDE setup.
Another photo with the cartrige cover off.

On 2020-05-12 09:33, 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!!!
> Regards, 
> Mark Marlette

>  http://www.cloud9tech.com
> mark at cloud9tech.com
> mark at gamecamaddict.com
>     On Tuesday, May 12, 2020, 08:25:12 AM CDT, John E. Malmberg
> <wb8tyw at qsl.net> wrote:
>  What is the largest CompactFlash card supported by the SuperIDE?
> Any way for software to have the SuperIDE to read all 512 bytes of the
> sectors?  To write all 512 bytes?
> Any way for software to read sectors off of CD-ROM connected to it?
> Regards,
> -John
> --
> Coco mailing list
> Coco at maltedmedia.com
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