[Oberon] Data transfer in large amounts

Magnus Karlsson magnus at saanlima.com
Thu Jul 14 10:07:49 CEST 2016

On 2/13/2016 3:24 AM, Paul Reed wrote:
> In the end, it was decided to place the Oberon filesystem at a fixed
> offset from the beginning of the disk.  This was a trivial change to the
> bootloader, keeping it easily-understandable and within one block ram
> (BRAM) of the FPGA.
> This meant that FAT-compatible data structures, and a reasonable-size and
> perhaps useful (256MB) FAT partition could still exist at the beginning of
> the disk.  If this FAT partition has nothing in it, it compresses very
> well and therefore does not significantly increase the RISC.img download
> time.

Another option for transferring data to/from the Oberon system would be 
to write a lightweight FAT disk access driver in Oberon and load/store 
files in the 256MB FAT partition that exists at the beginning of the SD 
card. This would allow any system that can mount the FAT partition to 
access the files.

There are several open-source lightweight FAT access code written in C 
or C++ for small microcontroller systems (like elm-chan's FatFS, 
http://elm-chan.org/fsw/ff/00index_e.html or the Arduino SD library, 
https://www.arduino.cc/en/Reference/SD) that might be used as a starting 
point for an Oberon version.


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