From owner-freebsd-questions Sun Sep 1 15:52:42 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0C9FE37B406 for ; Sun, 1 Sep 2002 15:52:41 -0700 (PDT) Received: from wonkity.com (wonkity.com [63.93.4.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2057543E72 for ; Sun, 1 Sep 2002 15:52:40 -0700 (PDT) (envelope-from wblock@wonkity.com) Received: from wonkity.com (localhost.wonkity.com [127.0.0.1]) by wonkity.com (8.12.1/8.11.6) with ESMTP id g81MqduF013280; Sun, 1 Sep 2002 16:52:39 -0600 (MDT) (envelope-from wblock@wonkity.com) Received: from localhost (wblock@localhost) by wonkity.com (8.12.1/8.12.1/Submit) with ESMTP id g81Mqd1W013277; Sun, 1 Sep 2002 16:52:39 -0600 (MDT)?g (envelope-from wblock@wonkity.com) Date: Sun, 1 Sep 2002 16:52:39 -0600 (MDT) From: Warren Block To: Matthew Seaman Cc: FreeBSD LIST Subject: Re: dd if=/dev/zero of=/dev/ad1 In-Reply-To: <20020901223639.GA12421@happy-idiot-talk.infracaninophi> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sun, 1 Sep 2002, Matthew Seaman wrote: > It's part of the IDE specification: 128k is the maximum IO transfer > size. Oh --- the equivalent figure for SCSI discs is 64kB. I'm reasonably certain that for SCSI it's 64K *blocks* of 512 bytes each, or 32M. Some systems may have driver limitations that break transfers up into 64K chunks, though. -Warren Block * Rapid City, South Dakota USA To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message