cvs commit: src/sys/dev/ata ata-all.c ata-all.h ata-chipset.cata-dma.c ata-pci.c ata-pci.h

[Alexander Leidinger]

On Tue, 08 Apr 2003 19:15:04 +0200
Dag-Erling Smorgrav <des at ofug.org> wrote:

> Nate Lawson <nate at root.org> writes:
> > Tagged queuing is orthogonal to caching.  TQ allows multiple transactions
> > to be passed to the drive, allowing it to order and aggregate the requests
> > as it thinks best.  TQ can be done with no cache because all the drive is
> > tracking is handles to transactions (typically 16 bit ids).  Think of it
> > as more like a pipeline than a cache.
> 
> It can't be done without cache, because you can't queue and reorder
> transactions without some sort of cache.

I like to think about it as a buffer, not a cache. A write-cache
acknowledges the write as soon as it hits the cache (and not the
physical storage) and talking about TQ as a cache makes me feel bad...

Bye,
Alexander.

-- 
              To boldly go where I surely don't belong.

http://www.Leidinger.net                       Alexander @ Leidinger.net
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