Date: Tue, 12 Jan 2010 09:55:15 -0800 From: Chuck Swiger <cswiger@mac.com> To: Pieter Verberne <pieterverberne@xs4all.nl> Cc: freebsd-doc@freebsd.org Subject: Re: Handbook 3.2.2: Freebsd a multiprocessing system? Message-ID: <B5084FD7-7964-4315-94EC-8D0BEA5ECEBC@mac.com> In-Reply-To: <20100112085245.GA89307@xs4all.nl> References: <20100112085245.GA89307@xs4all.nl>
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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
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