[Coco] cache sector 0? related question

[Aaron Wolfe]

Here's another one for the experts:

Is the area in LSN0 that actually contains data ever bigger than 64
bytes? NitrOS9 docs show PD.OPT section is from 0x20 to 0x3F... then..
nothing?  Of course I ask because 64 bytes is much easier to deal with
than 256.. but don't want to misunderstand something.
If I took that shortcut I would definitely add code on the server side
to abort caching if non zero was found in the area past 0x3f.  Quick
look with a hex editor shows nothing but 0 on a couple RBF images
here, but obviously something could write there, and in the coco world
that often means somebody does..

-Aaron

On Sat, Jan 25, 2014 at 11:05 AM, Aaron Wolfe <aawolfe at gmail.com> wrote:
> Its often been noticed that sector 0 of an RBF filesystem gets
> read/written an awful lot when doing nearly any disk I/O.  I've been
> working on the dw server some this morning and am being reminded of
> just how much.
>
> Would it be practical to cache this sector somewhere?  256 bytes is
> not tiny, but also not impossible to find in the typical system page.
> The logic for a simple write-through cache would not be very complex.
>  I guess I'm looking to the experts for reasons this can't work or
> should never be done before looking at how to do it :)  Any thoughts?
>
> -Aaron