Re: sdirno/sfileno sized

From: Adrian Chadd <adrian@dont-contact.us>
Date: Fri, 23 Mar 2001 21:05:50 +0800

On Thu, Mar 22, 2001, Henrik Nordstrom wrote:
> Adrian Chadd wrote:
>
> > COSS stores the disk offset in swap_filen. Henrik changed this a while
> > back to be 27 bits in the StoreEntry instead of 32 bits. Obviously
> > this breaks when you write *over* 16 meg to a COSS file.
>
> Unless you scale it up to a larger "blocksize"...

.. which I plan to do, when the current code is stable.
It needs to be tidied up a whole lot, but I think its
nearly sync-stable.

> > Therefore, in the interests of Adrian's sanity, make the swap_filen
> > 32 bits again.
>
> The sizes of sfileno and sdirno should be configurable at build time I
> think..

Perhaps.

>
> > And whilst we're at it, change sdirno to be a signed char,
> > reducing its size to 8 bits.
>
> So you actually increased it from 7 to 8 bits then...

.. since I upped the fileno from 25 to 32 bits, it only
semed logical to do for now.

COSS is nifty. I'm starting to get this evil idea in my mind
of how I could do a "rough LRU" which is based on the average LRU
of the stripe rather than of the objects, which would cut down
on memory useage quite significantly. Someone explained the
very high-level idea to me a year and a bit ago, but I'm only
now starting to get it ..

>
> /Henrik

Again, I say that COSS is neat. :)

ADrian

>

-- 
Adrian Chadd		"The fact you can download a 100 megabyte file
<adrian@creative.net.au>  from half way around the world should be viewed
			    as an accident and not a right."
					-- Adrian Chadd and Bill Fumerola
Received on Fri Mar 23 2001 - 06:06:00 MST

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