From owner-freebsd-hackers Wed Mar 4 18:45:24 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id SAA01597 for freebsd-hackers-outgoing; Wed, 4 Mar 1998 18:45:24 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from sendero.simon-shapiro.org (sendero-fxp0.Simon-Shapiro.ORG [206.190.148.34]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id SAA01505 for ; Wed, 4 Mar 1998 18:45:08 -0800 (PST) (envelope-from shimon@sendero-fxp0.simon-shapiro.org) Received: (qmail 17209 invoked by uid 1000); 5 Mar 1998 02:51:45 -0000 Message-ID: X-Mailer: XFMail 1.3-alpha-021598 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <199803050137.RAA23401@dingo.cdrom.com> Date: Wed, 04 Mar 1998 18:51:45 -0800 (PST) Reply-To: shimon@simon-shapiro.org Organization: The Simon Shapiro Foundation From: Simon Shapiro To: Mike Smith Subject: Re: Disk write caches Cc: Terry Lambert , hackers@FreeBSD.ORG, Remy NONNENMACHER Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG 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 The ones I saw in the store claimed to do DMA, but my knowledge of IDE is old, outdated.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 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message