From owner-freebsd-current Wed Mar 4 19:17:15 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id TAA08766 for freebsd-current-outgoing; Wed, 4 Mar 1998 19:17:15 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from firewall.scitec.com.au (firewall-user@fgate.scitec.com.au [203.17.180.68]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id TAA08754 for ; Wed, 4 Mar 1998 19:17:10 -0800 (PST) (envelope-from john.saunders@scitec.com.au) Received: by firewall.scitec.com.au; id NAA25849; Thu, 5 Mar 1998 13:16:52 +1000 (EST) Received: from mailhub.scitec.com.au(203.17.180.131) by fgate.scitec.com.au via smap (3.2) id xma025845; Thu, 5 Mar 98 13:16:51 +1000 Received: from hydra.scitec.com.au (hydra.scitec.com.au [203.17.182.101]) by mailhub.scitec.com.au (8.6.12/8.6.9) with ESMTP id NAA11492; Thu, 5 Mar 1998 13:16:45 +1000 Received: from scitec.com.au (saruman.scitec.com.au) by hydra.scitec.com.au with ESMTP (1.40.112.8/16.2) id AA139837804; Thu, 5 Mar 1998 14:16:44 +1100 Message-Id: <34FE191D.1D676AC3@scitec.com.au> Date: Thu, 05 Mar 1998 14:16:45 +1100 From: John Saunders Organization: SCITEC LIMITED X-Mailer: Mozilla 4.04 [en] (WinNT; I) Mime-Version: 1.0 To: shimon@simon-shapiro.org, freebsd-current@FreeBSD.ORG Subject: Re: silo overflows (Was Re: 3.0-RELEASE?) References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Simon Shapiro wrote: > [snip] Every 1KB, you write to disk [snip] If you use an IDE disk then 10 to 1 that's the problem. Particularly if the IDE driver is doing multi-sector transfers. Interrupts must be disabled during IDE PIO transfers (or you can risk data corruption) and the time taken to transfer, say 16 sectors, is significant. When Linux supported Intel Triton busmaster IDE the occurance of FIFO overflows disappeared on Triton boards. For example I can run 6 16550 ports under Linux using busmaster support without any FIFO overflows. However I have trouble running 2 at 57600 bps without FIFO overflows. The solution is to use either a SCSI disk system, or support busmastering IDE. The real problem is the crazy IRQ priorities of the PC architeture. Cheers. -- +------------------------------------------------------------+ . | John Saunders mailto:John.Saunders@scitec.com.au (Work) | ,--_|\ | mailto:john@nlc.net.au (Home) | / Oz \ | http://www.nlc.net.au/~john/ | \_,--\_/ | SCITEC LIMITED Phone +61 2 9428 9563 Fax +61 2 9428 9933 | v | "By the time you make ends meet, they move the ends." | +------------------------------------------------------------+ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message