[Oberon] RISC.img format

[Chris Burrows]

> -----Original Message-----
> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
> Paul Reed
> Sent: Saturday, 13 February 2016 9:55 PM
> To: ETH Oberon and related systems
> Subject: [Oberon] RISC.img format
> 
> So if you are using a nice operating system and you know what you are
> doing (because it allows dangerous commands such as dd) you can
> extract the Oberon file system from the image with a command like
> (262145 = 40001H = 80002H * 512 DIV 1024)
> 
>   dd if=RISC.img of=.OBERON.FS  obs=1024 ibs=1024 skip=262145
> 
> and you can even (sudo) write it directly back to a real SD-Card with
> something like
> 
>   dd if=.OBERON.FS of=/dev/disk1 obs=1024 ibs=1024 seek=262145
> 

I use a similar technique on Windows (I assume that is what you were
referring to as a not so nice operating system?) using a dd tool which I
downloaded from:

http://www.chrysocome.net/dd

I use it for backing up Project Oberon disk images from an 8Gb MicroSD card
onto a PC. Initially I tried this using Win32DiskImager but I couldn't find
a way of stopping it from copying the whole 8Gb :( 

You need to set the 'Run this program as an Administrator' property of
dd.exe to access raw physical devices.

The command I used was:
  
dd  if=\\.\PhysicalDriveN  of=ImageName.img  bs=1M  count=320  --progress

This just copies the first 320 MB from the disk which includes the full 64MB
Oberon partition. Substitute the device number of your SD Card for N. You
can get the number from the list of drives on your system:
  
Administrative Tools > Computer Management > Storage > Disk Management

On my system the SD card was shown as Disk 6 so I used
if=\\.\PhysicalDrive6.

I still use Win32DiskImager to write disk images to the SD cards from a PC
as I haven't been able to get dd to work in that direction. If anybody knows
how I'd be pleased to hear about it.

Regards,
Chris

Chris Burrows
CFB Software
http://www.astrobe.com/RISC5