Handbook 3.2.2: Freebsd a multiprocessing system?

[Chuck Swiger]

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