From: Mark Lord <liml@rtr.ca>
To: Sebastian Kuzminsky <seb@highlab.com>
Cc: linux-ide@vger.kernel.org
Subject: Re: what is hdparm doing?
Date: Tue, 28 Feb 2006 20:27:56 -0500 [thread overview]
Message-ID: <4404F89C.8040008@rtr.ca> (raw)
In-Reply-To: <E1FED6T-0004a4-LN@highlab.com>
Sebastian Kuzminsky wrote:
> Hi folks, hdparm's got me confused.
..
> "hdparm /dev/hda" says:
.
> DMA: mdma0 mdma1 *mdma2
> Cycle time: min=120ns recommended=120ns
> PIO: pio0 pio1 pio2 pio3 pio4
> Cycle time: no flow control=120ns IORDY flow control=120ns
..
The *mdma2 means, that if you were to issue a READ_DMA (or WRITE_DMA)
command to the drive, the drive is expecting the host to use
the multiword-dma-2 protocol and timings for it.
Meanwhile, the host may, at its option, simply use PIO commands (READ, WRITE)
instead of DMA, any time it chooses.
Drives have both a DMA mode, and a PIO mode, each of which is selected
and used independently of the other.
Cheers
next prev parent reply other threads:[~2006-03-01 1:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-28 22:13 what is hdparm doing? Sebastian Kuzminsky
2006-03-01 1:27 ` Mark Lord [this message]
2006-03-01 3:22 ` Sebastian Kuzminsky
2006-03-01 4:18 ` Mark Lord
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