Date: Thu, 20 Dec 2001 14:51:02 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Anthony Atkielski <anthony@freebie.atkielski.com> Cc: Jeremiah Gowdy <jeremiah@sherline.com>, Gilbert Gong <ggong@cal.alumni.berkeley.edu>, advocacy@FreeBSD.org Subject: Re: Microsoft Advocacy? Message-ID: <XFMail.011220145102.jhb@FreeBSD.org> In-Reply-To: <026b01c189a6$3bb4b6c0$0a00000a@atkielski.com>
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On 20-Dec-01 Anthony Atkielski wrote: > John writes: > >> Some said (rough paraphrase): >> >> FreeBSD is suitable for use as a desktop for >> specific circumstances. >> >> This is equivalent to: >> >> FreeBSD is suitable for use as a desktop for >> at least one circumstance. >> >> Jeremiah replied with: >> >> "I do not agree." >> >> Which is equivalent to: >> >> FreeBSD is not suitable for use as a desktop >> for at least one circumstance. >> >> Which is equivalent to: >> >> FreeBSD is not suitable for use as a desktop >> for any circumstance. > > Your logic is flawed. Your last two conclusions do not follow from the > first three statements. Hrm, ok, note that statement 3 is simply statement 2 with a "not" added due to the negation. Can you show the logic error regarding equivalence of either 1 and 2 or 3 and 4 then? > Consider this: > > SomeoneBelieves = OSFree && Suitability && Desktop && Specific; > JeremiahBelieves = !(OSType && Suitability && Desktop && Specific); Err, this is not valid. There aren't 4 statements there are two: (1) For a specific instance, (2) FreeBSD is valid as a desktop. > Now I'm getting worried about spin mutexes and locks. Are you completely > sure about those? Yes, I'm fairly sure. Do you have any notion of how Unix works? All its data protection was by disabling interrupts (short-term protection which is what spin mutexes provide) since it was designed for a UP machine. On SMP blocking interrupts is not sufficient protection because another CPU could be executing the same or similar code, hence the need to synchronize via a spin lock. However, if we know we are not SMP (i.e. a UP kernel) we don't have to worry about synchronizing with another CPU, and can simply disable interrupts. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-advocacy" in the body of the message
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