From owner-freebsd-questions Mon Aug 30 7:26:24 1999 Delivered-To: freebsd-questions@freebsd.org Received: from mailgw3a.lmco.com (mailgw3a.lmco.com [192.35.35.24]) by hub.freebsd.org (Postfix) with ESMTP id 0D4BB14D64 for ; Mon, 30 Aug 1999 07:26:22 -0700 (PDT) (envelope-from Jeffery.Cote@lmco.com) Received: from emss04g01.ems.lmco.com ([166.17.13.122]) by mailgw3a.lmco.com (8.8.8/8.8.8) with ESMTP id KAA06827 for ; Mon, 30 Aug 1999 10:23:29 -0400 (EDT) Received: from CONVERSION-DAEMON by lmco.com (PMDF V5.2-32 #38890) id <0FHA00J017XGJV@lmco.com> for questions@freebsd.org; Mon, 30 Aug 1999 10:23:29 -0400 (EDT) Received: from mon-exchange.lmcda.lmco.com ([158.183.100.43]) by lmco.com (PMDF V5.2-32 #38890) with SMTP id <0FHA00OOQ7WYAH@lmco.com> for questions@freebsd.org; Mon, 30 Aug 1999 10:22:24 -0400 (EDT) Received: by mon-exchange.lmcda.lmco.com with SMTP (Microsoft Exchange Server Internet Mail Connector Version 4.0.996.62) id <01BEF2D1.E7876790@mon-exchange.lmcda.lmco.com>; Mon, 30 Aug 1999 10:24:55 -0400 Date: Mon, 30 Aug 1999 10:22:06 -0400 From: "Cote, Jeffery" Subject: DMA limits? To: "'questions@freebsd.org'" Message-id: MIME-version: 1.0 Content-type: TEXT/PLAIN Content-transfer-encoding: 7BIT Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG We are currently looking to use the DMA to transfer data on a byte by byte basis from a given memory location to an I/O device. Currently we are having problems with the 64k barrier encoutered with the data segments for we are transferring data from a large array. Will we encounter this problem with the DMA transfer as well or is the DMA capable of accessing the full 4G physical memory pool (using an 8237 chip set)? thanks To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message