Date: Wed, 20 Feb 2002 22:17:56 +0100 From: Alex <FreeBSD@cybertron.tmfweb.nl> To: Alex <FreeBSD@cybertron.tmfweb.nl> Cc: =?ISO-8859-1?B?U/hyZW4gTmVpZ2FhcmQ=?= <neigaard@e-box.dk>, Alex <akruijff@dds.nl>, <questions@freebsd.org> Subject: Re: OT: Re: Max RAM supported by Hardware Message-ID: <15518324328.20020220221756@cybertron.tmfweb.nl> In-Reply-To: <14217053982.20020220215646@cybertron.tmfweb.nl> References: <1556477954.20020220210026@e-box.dk> <14217053982.20020220215646@cybertron.tmfweb.nl>
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Hello Alex, Wednesday, February 20, 2002, 9:56:46 PM, you wrote: A> Hello Søren, A> Wednesday, February 20, 2002, 9:00:26 PM, you wrote: SN>> Linux can as standard support up to 1GB RAM, if more is present you SN>> need to compile the kernel with support for the large amount of RAM. SN>> Linux also supports up to 64GB RAM, although 32bit only allows 4GB (as SN>> I understand it, I'm not an expert). SN>> What about FreeBSD, is it the same here, or how does it work in the SN>> worlds best OS? SN>> -- SN>> Med venlig hilsen/Best regards, SN>> Søren Neigaard mailto:neigaard@e-box.dk SN>> -- SN>> "Any sufficiently advanced bug is indistinguishable from a feature." SN>> To Unsubscribe: send mail to majordomo@FreeBSD.org SN>> with "unsubscribe freebsd-questions" in the body of the message A> My anwser if a short off-topic anwser, but you may just like it. A> Because one first has to look at the underlaying layer we first look A> at the hardware. A> A 32 bit adress structer allows for 2^32 = 2 * 1024^3 = 2G adressable A> memory locations. But there is a trick. We divered the adress in BASE A> and OFFSET. In the case of Linux (base on what you wrote) the base A> gets multiply by 32 (2^5). Then the offset is added to it. This is A> posible because the software-code and data is usaly near to each A> other, so we don't need to send the BASE alot. A> Then the software part: Sorry i don't know this. I overlooked something. An nother trick is to read more than just 1 byte, offcorse. It likly that this is being done with the CPU's that have (a lot) of registries (i.e. place where you store the base and offset, but also tempory storing place for data). Since a Pentium doesn't have any 8 (and 16) bits regestries. So your proberbly write about the 4G. This trick is just a nother factor. -- Best regards, Alex To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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