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Date:      Wed, 04 Mar 1998 18:51:45 -0800 (PST)
From:      Simon Shapiro <shimon@simon-shapiro.org>
To:        Mike Smith <mike@smith.net.au>
Cc:        Terry Lambert <tlambert@primenet.com>, hackers@FreeBSD.ORG, Remy NONNENMACHER <remy@synx.com>
Subject:   Re: Disk write caches
Message-ID:  <XFMail.980304185145.shimon@simon-shapiro.org>
In-Reply-To: <199803050137.RAA23401@dingo.cdrom.com>

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On 05-Mar-98 Mike Smith wrote:
>> > Not sure IMHO. Typical wait time before write starts is 20 to 50 ms or
>> > half the internal disk buffers. Far less than sync daemon.
>> 
>> Get a caching controller, they start at $250.00 for IDE ones.  I measure
>> 2us or less for a cache hit to such controller.
> 
> Do you know of any that do DMA?  That'd be something *very* much worth 
> supporting.

All The DPT controllers do DMA.  The PCI ones do only DMA, no pio anymore. 
But these are SCSI.  The IDE ones look like a standard IDE ``controller''. 
The ones I saw in the store claimed to do DMA, but my knowledge of IDE is
old, outdated.

----------


Sincerely Yours, 

Simon Shapiro
Shimon@Simon-Shapiro.ORG                      Voice:   503.799.2313

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