Re: Linux Kernel 2.6.6 IDE shutdown problems.

[Eric D. Mudama]

On Tue, May 25 at 11:05, Giuliano Pochini wrote:
> On Mon, 24 May 2004, Eric D. Mudama wrote:
>
> > Picture a nice fast drive doing 100 writes/second to the media... if
> > you give it over 200 writes at a time, it'll occupy your 2 seconds.
> > Newer drives with 8MB or larger buffers are certainly capable of
> > caching a lot more than 200 writes...
>
> Quite unlikely. Usually disks have a big cache but it can hold a very
> limited number of blocks. 8MB of cache is probably divided in 8 blocks
> of 1MB each.

Sorry, but that isn't true, unless some company is just plain stupid.

Everyone has different metrics for cache granularity based on their
cache architecture, but I can assure you that 8x 1MB segments is off
by 1-2 orders of magnitude, and has been for years.

In practice, depending on the workload, there may appear to only be 8
active segments as drives today can merge cache segments or other
similar things (architectually dependant), but the worst-case (best
case?) is significantly more.

--eric



--
Eric D. Mudama
edmudama@xxxxxxxxxxxxxxxxxxxxx

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