[Coco] nitros9 proposal - cache sector 0?

Steve 6809er at srbsoftware.com
Sat Jan 25 11:45:10 EST 2014


My problem with cache this sector is corruption.  This a very important 
bit of information of the file system and should the cache buffer get 
damaged by crash code on the CoCo side, you just lost the disk.

A CRC or other check would be needed to verify the data has not been 
corrupted.  But the CoCo doing this type of check could take as long as 
reading it from the server.  Don't forget that writing this sector back 
to the server will take longer because to updating the cache and the CRC.

Good idea, but caching this sector may not save the time that you are 
hoping for.

Steve

On 1/25/2014 8:05 AM, Aaron Wolfe 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
>
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