From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 4 Aug 2002 08:36:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 4 Aug 2002 08:36:08 -0400 Received: from pc2-cwma1-5-cust12.swa.cable.ntl.com ([80.5.121.12]:35063 "EHLO irongate.swansea.linux.org.uk") by vger.kernel.org with ESMTP id ; Sun, 4 Aug 2002 08:36:08 -0400 Subject: Re: latency while writing to pc-card disks/tapes From: Alan Cox To: Julian Bradfield Cc: linux-kernel@vger.kernel.org In-Reply-To: <15693.2431.358745.864511@toolo.dcs.ed.ac.uk> References: <15693.2431.358745.864511@toolo.dcs.ed.ac.uk> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.3 (1.0.3-6) Date: 04 Aug 2002 14:57:25 +0100 Message-Id: <1028469445.14195.17.camel@irongate.swansea.linux.org.uk> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Another thing that surprises me is that this runs the CPU at > full stretch, since the fan comes on. I find it hard to believe that > writing to a rather slow tape drive can fully exercise a 1GHz > processor continuously. > (It may be relevant for the tape that scsi dis/reconnect is disabled, > as it doesn't work for my card.) PCMCIA is PIO only. Your processor is hard at work sitting waiting for out instructions to complete across the low speed (8Mhz or so) PCMCIA bus. Cardbus might help immensely if there are suitable cardbus adapters around because a cardbus slot with a cardbus card (not a pcmica card) in it is basically pure PCI