From owner-freebsd-questions Tue Mar 12 15:49:03 1996 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id PAA02775 for questions-outgoing; Tue, 12 Mar 1996 15:49:03 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id PAA02766 for ; Tue, 12 Mar 1996 15:48:56 -0800 (PST) Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.12/8.6.9) id KAA00112; Wed, 13 Mar 1996 10:27:09 +1030 From: Michael Smith Message-Id: <199603122357.KAA00112@genesis.atrad.adelaide.edu.au> Subject: Re: non-blocking read ? To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Date: Wed, 13 Mar 1996 10:27:08 +1030 (CST) Cc: leisner@sdsp.mc.xerox.com, msmith@atrad.adelaide.edu.au, questions@freebsd.org In-Reply-To: <199603121806.TAA20924@labinfo.iet.unipi.it> from "Luigi Rizzo" at Mar 12, 96 07:06:55 pm MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-questions@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Luigi Rizzo stands accused of saying: > > Someone suggested doing async IO and handling SIGIO (I suppose this > refers to doing See my previous message regarding not being sure about this, and definitely check how harvest does it, I'm sure I was wrong earlier 8( > But how much data will be available when I get the SIGIO (or select > will return that I/O is possible) ? The amount I requested (assuming it > is available), or the system idea of a block, or what ? "some"; you call read and examine the return value to see how much you get. Thinking about it further, I don't see how this would work for disk I/O; it's not until the read itself is issued that the disk request is queued ... > Luigi Rizzo Dip. di Ingegneria dell'Informazione -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] Collector of old Unix hardware. "Where are your PEZ?" The Tick [[