From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Brown Subject: 32 bit processors / 64 bit processors Date: Wed, 21 Oct 2009 08:32:56 +0530 Message-ID: <7783925d0910202002ubcd5328nd8c82bb11e5f84ea@mail.gmail.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:date:message-id:subject :from:to:content-type; bh=VLHIb5SKkIl4tS3j8iiQpl0DTLQz1fjALge+P1qBHok=; b=K1upNAQGmEMWF1+Alf3fWjFvvmgYxOM3kVlYUVVELZu+lAuMRiBJivm3Jg5qy9JvRj 5y4oghPYv+mJpGNGrnRWaW4nBMYcWEX4R3RqOxHiqQ078UudTS6bPs5iNsz9xgsmP/we fnrsdCi70TbglcUAJus8X2fsustj4/Ha+Fw1U= Sender: linux-newbie-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernelnewbies , linux-newbie@vger.kernel.org Hi, Firstly, I'm trying to understand what exactly characterizes a procesor or an operating system as 32bit / 64 bit. I've read that it means the "native word size" of a machine. But what exactly is that? Register size? Address bus size? Anything else? Secondly, I'm trying to understand what exactly does a sizeof(int) depend on when we say it is "platform specific". Is it dependent of compiler being 32bit / 64 bit? Or the OS being 32bit / 64 bit? Or the processor being 32 / 64 bit? Lastly, How are "sizes" of compiler / OS / processor inter related? Here is my understanding. A 32 bit processor can only be running a 32 bit OS. A 64 bit processor may run a 32 or a 64 bit OS. A 32 bit compiler genrates code only to be run on a 32 bit OS; ditto for 64 bit. Is this right? TIA, Rick -- To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs