From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 4 Sep 2001 11:33:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 4 Sep 2001 11:33:05 -0400 Received: from lightning.swansea.linux.org.uk ([194.168.151.1]:25867 "EHLO the-village.bc.nu") by vger.kernel.org with ESMTP id ; Tue, 4 Sep 2001 11:32:59 -0400 Subject: Re: Should I use Linux to develop driver for specialized ISA card? To: fred@arkansaswebs.com (Fred) Date: Tue, 4 Sep 2001 16:36:53 +0100 (BST) Cc: alan@lxorguk.ukuu.org.uk (Alan Cox), rastos@woctni.sk, linux-kernel@vger.kernel.org In-Reply-To: <01090410264000.14864@bits.linuxball> from "Fred" at Sep 04, 2001 10:26:40 AM X-Mailer: ELM [version 2.5 PL6] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: From: Alan Cox Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > I'm curious, Alan, Why? I'm a hardware developer, and I would have assumed > that linux would have been ideal for real time / embedded projects? (routers > / controllers / etc.) Is there, for instance, a reason to suspect that linux > would not be able to respond to interrupts at say 8Khz? > of course I know nothing of rtlinux so I'll read. Routers aren't real time for example The specific issues you have to watch are mostly from user space. Kernel irq handlers will run very rapidly providing another driver is not holding the interrupts off for a long time. Certain types of PC device require this (some IDE controllers for example). You also have to watch PCI graphics cards some of which will stall the PCI bus locking the CPU off it for milliseconds at a time [its a hack to get better benchmark numbers - sick isnt it] So with the kernel you should be able to respond to irqs at 8Khz, with RtLinux you can make that a definitive mathematically hard guarantee Depends which you need Alan