[Oberon] RISC.img format

[Paul Reed]

Hi Peter,

> ETH PC Native Oberon [...] and FPGA Oberon [have] a b-tree as primary
structure of the file system.  Both FS  are "flat".  Both limit
> the length of a file name to 31 or 32 characters.  They differ
> in upper limit on file size or on number of files?  Better
> algorithms implement the newer FS?

The biggest actual difference, and probably the hardest to spot by just
comparing the source code, is that the on-disk data structures are
different due to the lack of a 16-bit integer type in Oberon-07.

What is a LONGINT in Oberon-88, is an INTEGER in Oberon-07 (which is 32-bit).

What is an INTEGER in Oberon-88 (which is 16-bit), had to be actually
changed (effectively to LONGINT from an Oberon-88 point of view) for the
2013 edition.

HTH,
Paul