Date   : Wed, 15 Jul 2009 08:26:14 +0100
From   : info@... (Sprow)
Subject: Master ethernet upgrade

In article <090715005506@...>,
   Jonathan Graham Harston <jgh@...> wrote:
> > Message-ID: <14232B91710641DBB94040E29D3F5398@...>
>  
> "Mark Haysman" wrote:
> > > stick, which I assume is FAT formatted, would be read by RISC
> > > OS' DOSFS which stores filetypes in a reserved field (which
> > > Windows usually zeros) and also can't fit the full 64 bit
> > > load/exec addresses into the native catalogue format. It also
>  
> Petrov's DOSFS <http://mdfs.net/Apps/Filing> manages it. The DOS Technical
> Reference Manual states: bytes 12-21 : Reserved

Sadly, the rest of the world has move on since that parchment was scribed,
bytes 12 to 21 are no longer reserved.

  12 is for private use by Windows NT.
  13-17 are the creation time & date.
  18-19 are the last accessed date.
  20-21 are reserved.
 
> Petrov DOSFS puts the load&exec in 12-15 and 16-19.

Windows actively zeros the reserved fields, and may even fault duff looking
creation times (eg. where the seconds byte is > 60) - I can't remember -
which effectively rules them out.

I'd also say it's generally not a good idea to store data in fields marked
as reserved for that very reason,
Sprow.