[Coco] SuperIDE backup/restore

[Mark McDougall]

On 29/07/2013 11:21 AM, Retro Canada wrote:

> looks like the cf ide firmware plays dirty when there is a partition on
> it. superide relays on sector count only, while the pc could use head
> cylinder geometry.

That doesn't make sense to me. A 'partition' on an IDE drive is a high level 
concept that has no meaning in the ATA specification. CF card firmware has 
no knowledge of any such thing, which after all is simply sector data 
interpreted a certain way by PC BIOS's and OS's.

In your second comment you could have a valid point, but it is totally 
unrelated to the first.

> my very own experience since i recently purchased a cf card: i tried
> everything and it wasn't working until i reformated and deleted  all
> partitions in linux then write to the device since there is no partition
> with sudo dd of=/dev/sdb

Any version of dd *should* treat the device as a raw block device. Under 
linux this is certainly the case, but the win32 'dd' is to a degree at the 
mercy of the Windows OS and I wouldn't be surprised if there was some 
munging going on that breaks certain rules.

Indeed windows XP didn't support partitions at all on removable devices, and 
you had to run proprietary software in the early days to get around that 
problem. With the advent of USB sticks that changed, though I'm not 
intimately familiar with the exact details, but IIRC some of them simply 
didn't report themselves as removable devices.

Regardless of any of the above, using dd under linux to read an image from 
the source CF and write to the destination CF should produce an exact copy 
regardless of the contents of the latter prior to the operation. dd (linux) 
uses raw device geometry which again knows nothing of 'partitions'.

Regards,

-- 
|              Mark McDougall                | "Electrical Engineers do it
|  <http://members.iinet.net.au/~msmcdoug>   |   with less resistance!"