Date: Sun, 01 Feb 2004 11:06:20 -0800 From: "Jin Guojun [NCS]" <j_guojun@lbl.gov> To: Michal Pasternak <michal@pasternak.w.lub.pl> Cc: freebsd-hardware@freebsd.org Subject: Re: About CD-RW Message-ID: <401D4E2C.805C33AB@lbl.gov> References: <opr2nvq7ncw41ezb@smtp.hotpop.com> <20040131232022.GA20827@pasternak.w.lub.pl>
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Michal Pasternak wrote:
> > And another little question. What is better to have both CD-RW and HDD on
> > one ata0 (master and slave) or HDD on ata0 and CD-RW on ata1? What gives
> > best performance? I think that best one is when they are on different,
> > bacause it become possible to only read via one and only write via other
> > while copying data. Is it that way?
>
> Many people told me, that it is the best to have them on separate channels,
> if this is possible.
This really depends on IDE controllers. Most IDE controllers do not provide
two separated IDE channels. They only have one internal IDE channel to fan out
four connectors. Testing shows that two IDE drives on two buses can affect each
other.
So, it does not really matter where you connect to. In this case,
using two buses may reduce the secondary bus arbitration, and gives a
little bit better throughput.
A few IDE controllers are real two channels, for example AMD MPX chipset.
Some one told that nVidia PCI chipset is similar to MPX. Under this
circumstance,
using two buses will make difference on performance.
-Jin
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