Re: [Libcdio-devel] Disabling Drive Cache for Paranoia

[Jason Voegele]

On Wednesday 21 June 2006 10:13, Peter Creath wrote:
> How big is your drive's cache?  There's a setting in the
> cdrom_paranoia_t that you pass to paranoia_read() that specifies how
> many sectors cdparanoia needs to read to exhaust your cache.
> Specifically, it's cdrom_paranoia_t.readahead.

So I am responding to a message that is nearly a year old, as I've now gotten 
to the point where I can actually make use of this information.

I have looked through the libcdio and cdparanoia sources, and I have found the 
cdrom_paranoia_t.readahead setting mentioned above.  Unfortunately, this 
setting is hard coded to the value 150, and is buried in an "opaque" 
structure so that it is not possible to set the value programatically from an 
external application.  In order to change this value from 150 to something 
more appropriate for a drive with a bigger cache, it is necessary to modify 
the source code, recompile, relink, etc. etc..

It would be of greate benefit to me to have this setting be exposed in some 
way so that I could set its value from my application.  What are your 
thoughts on this?  Is there a fundamental reason that the value is hard coded 
to 150?  Would exposing this value to applications be of benefit to anyone 
else?

If I were to put together a patch that accomplishes this, would it be 
something that could be incorporated into libcdio's paranoia library?

-- 
Jason Voegele
The degree of technical confidence is inversely proportional to the
level of management.

pgprdf1Pydk37.pgp
Description: PGP signature