From owner-freebsd-doc@FreeBSD.ORG Tue Jan 12 17:55:16 2010 Return-Path: Delivered-To: freebsd-doc@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 77808106568B for ; Tue, 12 Jan 2010 17:55:16 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from asmtpout028.mac.com (asmtpout028.mac.com [17.148.16.103]) by mx1.freebsd.org (Postfix) with ESMTP id 650E78FC16 for ; Tue, 12 Jan 2010 17:55:16 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=us-ascii Received: from cswiger1.apple.com ([17.227.140.124]) by asmtp028.mac.com (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTPSA id <0KW500H6ZB439830@asmtp028.mac.com> for freebsd-doc@freebsd.org; Tue, 12 Jan 2010 09:55:15 -0800 (PST) From: Chuck Swiger In-reply-to: <20100112085245.GA89307@xs4all.nl> Date: Tue, 12 Jan 2010 09:55:15 -0800 Message-id: References: <20100112085245.GA89307@xs4all.nl> To: Pieter Verberne X-Mailer: Apple Mail (2.1077) Cc: freebsd-doc@freebsd.org Subject: Re: Handbook 3.2.2: Freebsd a multiprocessing system? X-BeenThere: freebsd-doc@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Documentation project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Jan 2010 17:55:16 -0000 Hi-- On Jan 12, 2010, at 12:52 AM, Pieter Verberne wrote: > Section 3.2.2 of the FreeBSD handbook says: > "FreeBSD is a multiuser, multiprocessing system. This is the formal > description that is usually given to a system that can be used by many > different people, who simultaneously run a lot of programs on a single > machine." > > Isn't running programs simultaneously called time-sharing? No. A time-sharing or batch processing system traditionally used to process entire jobs to completion-- think of Hollerith card based machines or early cooperative multitasking implementations and you'll get the idea. Because FreeBSD has a scheduler interrupt firing at typically HZ=100 or 1000, which will pre-empt any userland task and allow other userland tasks to run without any of them being explicitly coded to yield the CPU, FreeBSD is correctly described as a "preemptive multitasking OS". > Wikipedia says: > "Multiprocessing is the use of two or more central processing units > (CPUs) within a single computer system." > > Okay, FreeBSD might use more than one CPU at the time, but the handbook > is still incorrect I think. FreeBSD does support multiprocessing per that definition also. Regards, -- -Chuck